10 New Tools: Pomodoro Timer, Chmod Calculator, and More

# 10 New Tools: Pomodoro Timer, Chmod Calculator, and More

Another massive update. We have added 10 new tools across multiple categories, pushing the total to 46 free tools. We also shipped meaningful accessibility improvements that push our Lighthouse accessibility score higher. This post covers every new tool in depth - with practical guides, real-world use cases, and code examples for each one.

New Tool: Pomodoro Timer

Stay focused with a customizable work/break timer using the Pomodoro technique. Features customizable durations, session tracking, circular progress indicator, and audio notifications - all running in your browser.

The Pomodoro Technique - The Method Behind the Timer

The Pomodoro Technique was developed by Francesco Cirillo in the late 1980s. The method is simple:

1. Choose one task to focus on
2. Set a timer for 25 minutes (one "pomodoro")
3. Work exclusively on that task until the timer rings
4. Take a 5-minute break
5. After four pomodoros, take a longer 15-30 minute break

The core insight is that time pressure, combined with permission to stop and rest, allows for higher-quality sustained focus than attempting to work indefinitely.

Why it works for developers:

Developers frequently fall into two counterproductive patterns: shallow multitasking (constantly switching context between tasks, Slack, email) or unhealthy hyperfocus (working for hours without breaks, ending the day exhausted). The Pomodoro technique provides a structured framework that avoids both extremes.

The 25-minute blocks are short enough to feel tractable even when facing a difficult problem. The mandatory breaks prevent the mental fatigue that comes from sustained high-concentration work. And the session counter gives you a concrete metric of productivity - five completed pomodoros is a productive day by any measure.

Customizing the Timer

The Pomodoro Timer lets you adjust durations to match your working style. The 25/5 split is a starting point, not a prescription:

Common timer configurations:

The 90-minute work block corresponds to ultradian rhythms - natural cycles in human alertness that some researchers identify as 90-minute periods. If you find 25 minutes feels too short (common for deep work tasks like implementing a complex algorithm or writing a long article), try 50 or 90 minute blocks.

Browser Notifications for Pomodoro Alerts

The timer uses the Web Notifications API to send alerts when a session ends - even if you have switched to another tab:

// Request notification permission on first use
const requestNotificationPermission = async () => {
  if ('Notification' in window) {
    const permission = await Notification.requestPermission();
    return permission === 'granted';
  }
  return false;
};

// Show notification when session ends
const notifySessionEnd = (sessionType) => {
  if (Notification.permission === 'granted') {
    new Notification('ToolBox Pomodoro', {
      body: sessionType === 'work'
        ? 'Focus session complete. Time for a break!'
        : 'Break over. Back to work!',
      icon: '/icons/icon-192.png',
    });
  }
};

This is important for a timer tool - you will often be working in a code editor or other application during your pomodoro session. The browser notification appears as a system-level alert that does not require you to be looking at the ToolBox tab.

Tracking Productivity with the Session Counter

The timer tracks completed pomodoros in the current session. Research on deliberate practice suggests that four to six high-quality focus sessions per day is roughly the sustainable ceiling for most knowledge workers. Tracking your session count gives you a concrete measure of whether you are hitting that range.

When you close the tab, the session count resets. This is by design - each day starts fresh. The goal is not to accumulate an infinite score but to hit a daily target consistently.

Pairing the Pomodoro Timer with Other Tools

A common developer workflow:

1. Before the pomodoro: use the Markdown Table Generator to outline the tasks for the session
2. During the pomodoro: use whatever tool is needed - JSON Formatter, Regex Tester, Diff Checker
3. During the break: step away from the screen entirely

New Tool: Chmod Calculator

An interactive Unix file permissions builder. Toggle read, write, and execute permissions for owner, group, and others. See numeric (octal) and symbolic notation update in real time. Includes common presets.

Unix File Permissions - The Complete Guide

File permissions are one of the foundational concepts of Unix and Linux systems. Every file and directory has three categories of permissions for three categories of users:

Permission categories:

• r - Read (4 in octal)
• w - Write (2 in octal)
• x - Execute (1 in octal)

User categories:

• u - Owner (the user who owns the file)
• g - Group (users who belong to the file's group)
• o - Others (everyone else)

The octal representation:

Each user category gets a number from 0-7 by summing the active permissions:

The three-digit octal notation:

chmod 755 means:

• Owner: 7 (rwx) - read, write, execute
• Group: 5 (r-x) - read, execute
• Others: 5 (r-x) - read, execute

Reading the symbolic notation `ls -la` output:

-rwxr-xr-x  1 alice  staff  1234  Jan 1 12:00  script.sh
drwxr-xr-x  5 alice  staff   160  Jan 1 12:00  directory/
-rw-r--r--  1 alice  staff   567  Jan 1 12:00  config.json

Common Chmod Values and When to Use Them

Security-sensitive defaults:

SSH private keys must be set to 600 or the SSH client will refuse to use them:

chmod 600 ~/.ssh/id_rsa
chmod 700 ~/.ssh/

Web server directories typically use 755 for directories and 644 for files:

find /var/www/html -type d -exec chmod 755 {} \;
find /var/www/html -type f -exec chmod 644 {} \;

The chmod Command Syntax

Using octal notation:

chmod 755 script.sh
chmod 644 config.json
chmod 600 .env
chmod -R 755 /var/www/html  # Recursive - applies to all files and subdirectories

Using symbolic notation:

# Add execute permission for owner
chmod u+x script.sh

# Remove write permission for group and others
chmod go-w important.txt

# Set exact permissions (= resets then sets)
chmod u=rwx,g=rx,o=rx script.sh

# Make all files in directory readable by everyone
chmod a+r *

Symbolic notation operators:

The Special Permission Bits

Beyond the standard 9 permission bits, Unix has three special bits:

SetUID (SUID) - 4 in the fourth octal position:

When set on an executable, the program runs with the permissions of the file owner rather than the user executing it. Used by commands like passwd that need temporary root access.

chmod 4755 /usr/bin/example  # setuid executable

SetGID (SGID) - 2 in the fourth octal position:

On a directory, new files created inside inherit the group of the directory rather than the user's primary group. Useful for shared project directories.

chmod 2775 /shared/project  # setgid directory

Sticky bit - 1 in the fourth octal position:

On a directory, only the file owner can delete files inside, even if others have write permission. Used on /tmp.

chmod 1777 /tmp  # sticky bit

The Chmod Calculator handles standard permissions. For setuid/setgid/sticky bits, use the command line directly.

New Tool: Aspect Ratio Calculator

Calculate and convert aspect ratios for images, videos, and screens. Lock the ratio and calculate missing dimensions. Includes presets.

Why Aspect Ratios Matter

An aspect ratio is the proportional relationship between the width and height of a rectangle. 16:9 means the width is 16 units for every 9 units of height. Aspect ratios are critical in:

• Responsive images - Preventing layout shift when images load (CLS score)
• Video embeds - Making YouTube/Vimeo embeds properly fill their containers
• Photography - Cropping images to standard print sizes
• Screen design - Designing for specific device viewport ratios

Common Aspect Ratios Reference

Maintaining Aspect Ratio in CSS

The padding-top hack (legacy approach):

/* Container maintains 16:9 aspect ratio */
.video-container {
  position: relative;
  width: 100%;
  padding-top: 56.25%; /* 9/16 = 0.5625 = 56.25% */
}

.video-container iframe {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
}

The modern `aspect-ratio` property (widely supported since 2021):

/* Clean, no hacks needed */
.video-container {
  width: 100%;
  aspect-ratio: 16 / 9;
}

.video-container iframe {
  width: 100%;
  height: 100%;
}

/* Apply to images to prevent layout shift */
img {
  width: 100%;
  aspect-ratio: 3 / 2;
  object-fit: cover;
}

The aspect-ratio CSS property is now supported in all modern browsers and is the recommended approach. The padding-top hack is legacy code you will encounter in older codebases.

Preventing CLS (Cumulative Layout Shift) with aspect ratios:

Layout shift happens when images load and push content down the page. Setting explicit width, height, and aspect-ratio prevents this:

<!-- Add width and height attributes - browser reserves space -->
<img
  src="hero.jpg"
  alt="Hero image"
  width="1200"
  height="630"
  loading="lazy"
>

img {
  max-width: 100%;
  height: auto; /* maintains intrinsic aspect ratio */
}

The browser reads the width and height HTML attributes to calculate the aspect ratio before the image loads, then reserves that space. When the image loads, there is no shift.

New Tool: CSS Units Converter

Convert between px, rem, em, vw, vh, and percentages. Set your base font size and viewport dimensions for accurate conversions.

Understanding CSS Length Units

CSS has over a dozen length units divided into absolute and relative categories. Choosing the right unit for each property significantly affects responsiveness and accessibility.

Absolute units (fixed, context-independent):

Relative units (context-dependent):

The rem vs em Decision

This is one of the most common sources of confusion in CSS:

`em` is relative to the font-size of the element's parent (or the element itself for font-size). This means it compounds:

html { font-size: 16px; }
.parent { font-size: 1.25em; }     /* 16 × 1.25 = 20px */
.child { font-size: 1.25em; }      /* 20 × 1.25 = 25px - not 20! */
.grandchild { font-size: 1.25em; } /* 25 × 1.25 = 31.25px */

This compounding makes em difficult to reason about in deeply nested components.

`rem` always refers to the root (html) element's font-size. It is consistent regardless of nesting:

html { font-size: 16px; }
.any-element { font-size: 1.25rem; }   /* Always 16 × 1.25 = 20px */
.nested { font-size: 1.25rem; }        /* Still 20px */
.deeply-nested { font-size: 1.25rem; } /* Still 20px */

Rule of thumb:

• Use rem for font sizes and most spacing - predictable, no compounding
• Use em for padding and margins when you want them to scale relative to the component's own font size
• Use px for borders, outlines, and values that should not scale with user font preferences
• Use vw/vh for truly viewport-relative sizing (hero sections, full-screen layouts)

CSS Unit Conversion Quick Reference

Assuming default html { font-size: 16px } and 1920×1080 viewport:

The CSS Units Converter lets you set your actual base font size and viewport dimensions for accurate conversions specific to your project.

New Tool: URL Slug Generator

Convert any text into clean, SEO-friendly URL slugs. Handles diacritics, special characters, and multiple separator styles.

What Makes a Good URL Slug

A URL slug is the human-readable part of a URL that identifies a specific page. For a blog post titled "How to Center a Div in CSS (2026)", the slug might be how-to-center-a-div-in-css-2026.

Characteristics of a good slug:

• All lowercase
• Words separated by hyphens (not underscores - search engines treat hyphens as word separators)
• No special characters, punctuation, or symbols
• Meaningful without the page title visible
• Concise - remove stop words like "a", "the", "in", "of" if the slug is too long
• Stable - changing a slug breaks existing links and loses SEO value

How Slug Generation Works

The Slug Generator applies a series of transformations:

1. Normalize Unicode - Convert accented and special characters to ASCII equivalents

Ünïcödé → Unicode
café → cafe
naïve → naive

1. Lowercase everything

How to Center a Div → how to center a div

1. Replace separators - Spaces, underscores, and other word separators become hyphens

how to center a div → how-to-center-a-div

1. Remove remaining non-alphanumeric characters

"hello, world!" → hello-world
C# .NET Tips → c-net-tips

1. Remove consecutive hyphens

hello--world → hello-world

1. Trim leading and trailing hyphens

-hello-world- → hello-world

Implementing slug generation in JavaScript:

function generateSlug(text) {
  return text
    .normalize('NFD')                          // Decompose accented chars
    .replace(/[\u0300-\u036f]/g, '')          // Remove diacritics
    .toLowerCase()
    .trim()
    .replace(/[^\w\s-]/g, '')                 // Remove special chars
    .replace(/[\s_-]+/g, '-')                 // Spaces/underscores to hyphens
    .replace(/^-+|-+$/g, '');                 // Trim leading/trailing hyphens
}

generateSlug('How to Center a Div in CSS (2026)')
// "how-to-center-a-div-in-css-2026"

generateSlug('C# and .NET: Best Practices')
// "c-and-net-best-practices"

generateSlug('Café au lait - recipe')
// "cafe-au-lait-recipe"

SEO Implications of URL Structure

URL slugs directly affect search engine optimization:

Keyword presence: Including the primary keyword in the URL slug is a confirmed ranking factor. A URL like /blog/best-practices-for-css-performance signals to search engines what the page is about more clearly than /blog/post-123456.

URL length: Shorter URLs are easier to share, remember, and read. Search engines show URLs in results snippets. URLs over 60-70 characters may be truncated in search results. Remove stop words from slugs when the slug is getting long.

Slug stability: Once a URL is indexed, changing it requires setting up a 301 redirect from the old URL to the new one. Missing redirects cause 404 errors that erode search rankings and break backlinks. Design slugs for longevity - avoid including dates or version numbers unless they are part of the content identity.

Separators: Use hyphens, not underscores. Google treats css-performance-tips as three separate words, but css_performance_tips as one compound word. Hyphens win for SEO.

New Tool: JavaScript Minifier

Minify JavaScript code by removing whitespace, comments, and unnecessary characters. See original and minified file sizes with percentage savings.

What Minification Does

JavaScript minification reduces file size without changing the code's functionality. The JavaScript Minifier applies several transformations:

Whitespace removal - All unnecessary spaces, tabs, and newlines are removed:

// Before
function add(a, b) {
    return a + b;
}

// After
function add(a,b){return a+b;}

Comment removal - All // and /* */ comments are stripped:

// Before
/* Calculate the user's full name */
function getFullName(user) {
    // Combine first and last with a space
    return user.firstName + ' ' + user.lastName;
}

// After
function getFullName(user){return user.firstName+' '+user.lastName;}

Variable name mangling (in advanced mode) - Long variable names are replaced with single or double letters:

// Before
function calculateTotalPrice(basePrice, taxRate, discount) {
    return (basePrice * (1 - discount)) * (1 + taxRate);
}

// After (with name mangling)
function c(a,b,d){return(a*(1-d))*(1+b);}

Dead code elimination - Code that can never be reached is removed:

// Before
function getVersion() {
    return '2.0';
    console.log('This never runs'); // Dead code
}

// After
function getVersion(){return'2.0';}

Minification Size Savings Reference

Real-world size savings from minification:

Minification in Build Pipelines

For production JavaScript, minification should happen automatically in your build pipeline rather than manually. The JavaScript Minifier is useful for:

• Quick manual minification of small scripts or utilities
• Verifying what a minifier produces without setting up a full build
• Understanding how minification works
• Processing third-party scripts that are not part of your build system

Vite (automatic minification with Rollup + Terser):

// vite.config.ts - minification is on by default in production mode
export default {
  build: {
    minify: 'terser', // or 'esbuild' (default, faster)
    terserOptions: {
      compress: {
        drop_console: true, // Remove console.log in production
      }
    }
  }
}

Next.js (automatic via SWC minifier):

// next.config.js - SWC minification is on by default
const nextConfig = {
  swcMinify: true, // Default: true in Next.js 13+
};

New Tool: Color Shade Generator

Generate a complete Tailwind-style shade scale (50-950) from any base color. Copy individual shades or export the entire palette as CSS variables or Tailwind config.

The Tailwind Color Scale System

Tailwind CSS uses a numeric scale from 50 to 950 to represent a spectrum of shades from very light to very dark. Each color family (blue, red, green, etc.) follows this 11-step scale:

The Color Shade Generator creates this full scale from a single base color, which is typically the 500 value.

Exporting as CSS Custom Properties

Once you have generated a shade scale, you can export it as CSS custom properties for use in any project - not just Tailwind:

:root {
  --brand-50:  #eff6ff;
  --brand-100: #dbeafe;
  --brand-200: #bfdbfe;
  --brand-300: #93c5fd;
  --brand-400: #60a5fa;
  --brand-500: #3b82f6;  /* Base color */
  --brand-600: #2563eb;
  --brand-700: #1d4ed8;
  --brand-800: #1e40af;
  --brand-900: #1e3a8a;
  --brand-950: #172554;
}

Using the scale in components:

.button-primary {
  background-color: var(--brand-500);
  color: white;
}

.button-primary:hover {
  background-color: var(--brand-600);
}

.button-primary:active {
  background-color: var(--brand-700);
}

.button-primary:disabled {
  background-color: var(--brand-200);
  color: var(--brand-400);
  cursor: not-allowed;
}

Exporting as Tailwind Config

If you are using Tailwind, the generator can produce a config block you can paste directly into tailwind.config.js:

// tailwind.config.js
module.exports = {
  theme: {
    extend: {
      colors: {
        brand: {
          50:  '#eff6ff',
          100: '#dbeafe',
          200: '#bfdbfe',
          300: '#93c5fd',
          400: '#60a5fa',
          500: '#3b82f6',
          600: '#2563eb',
          700: '#1d4ed8',
          800: '#1e40af',
          900: '#1e3a8a',
          950: '#172554',
        },
      },
    },
  },
}

You can then use these colors with all Tailwind utilities: bg-brand-500, text-brand-700, border-brand-200, etc.

New Tool: IP Address Lookup

Instantly see your public IP address with geolocation data - city, country, timezone, and ISP. Useful for verifying VPN connections and network troubleshooting.

What Your Public IP Address Reveals

Your public IP address is assigned by your ISP and is visible to every website and service you connect to. From an IP address alone, it is possible to determine (with varying accuracy):

• Country and region - highly accurate
• City - moderately accurate (within 25-50 miles typically)
• ISP and organization - highly accurate
• Timezone - derived from geography
• Whether it is a VPN, proxy, or Tor exit node - increasingly detectable

The IP Address Lookup tool shows you exactly what information your IP address exposes.

Common Use Cases

Verifying VPN connections:

When you connect to a VPN, your public IP address should change to an IP owned by the VPN provider. Use the lookup tool before and after connecting:

Before VPN: 203.0.113.45 - ISP: Comcast, City: Chicago, US

After VPN: 198.51.100.22 - ISP: NordVPN, City: Amsterdam, NL

If the city and ISP do not change after connecting, your VPN connection failed to establish (or you are using a split-tunnel configuration that does not route browser traffic through the VPN).

Development and testing:

When building applications that behave differently based on geographic location (content licensing, language defaults, shipping zones), you need to test from different IP addresses. Knowing your current apparent location helps you understand what users in your region will see.

Debugging network issues:

When troubleshooting connectivity problems, knowing your public IP helps you:

• Verify you are behind a NAT (common in home networks) or have a direct public IP
• Check whether your IP is on any blocklists that might explain connection failures
• Provide accurate information when contacting ISP support

Corporate network verification:

In enterprise environments, some internal resources are restricted to company IP ranges. Verifying that you are presenting the correct corporate IP (when on VPN or company network) helps debug access issues.

Static vs Dynamic IP Addresses

Most residential internet connections receive a dynamic IP address - it can change when your router reconnects to your ISP, typically every few days to weeks. Business connections often have static IPs that never change.

For servers, databases, and services that need consistent network identity, static IPs are essential. Dynamic IPs can cause problems for:

• IP allowlisting in firewalls and database access controls
• SSL certificate validation for some configurations
• Email deliverability (dynamic IP ranges have poor reputation scores)

New Tool: Letter and Character Frequency Analyzer

Analyze character frequency in any text with visual bar charts. Supports case-sensitive and case-insensitive modes.

Frequency Analysis - Theory and Applications

Character frequency analysis is the study of how often each character appears in a piece of text. It has applications in cryptography, linguistics, text compression, and writing analysis.

English language character frequencies (approximate):

Cryptographic Applications

Caesar cipher analysis:

A Caesar cipher shifts each letter by a fixed amount. To break it, perform frequency analysis on the ciphertext. The most common letter in the ciphertext is likely e in the original. The shift amount is the distance from e to whatever letter is most frequent.

Ciphertext: WKH TXLFN EURZQ IRA
Most frequent letter in ciphertext: 'K'
'K' is 6 positions after 'E' (the expected most common letter)
Therefore shift is likely 3 (could also be tried with 6)
Decrypted with shift 3: THE QUICK BROWN FOX

Substitution cipher analysis:

In a simple substitution cipher, each letter is consistently replaced by a different letter. Frequency analysis combined with pattern recognition (common two-letter words: "the", "and", "is"; common single-letter words: "a", "I") can break these ciphers.

Writing Analysis Applications

Character and word frequency analysis reveals patterns in writing that are not visible from normal reading:

• Vocabulary richness - Comparing unique words to total words reveals how varied the vocabulary is
• Sentence structure patterns - High frequency of certain function words indicates writing style
• Language identification - The character frequency profile of text strongly indicates which language it is written in
• Authorship analysis - Authors have statistically consistent character and word usage patterns; this can be used to identify unknown authors

Applications in Code Analysis

For developers, character frequency analysis has technical uses:

Compression algorithm design - Huffman coding assigns shorter bit patterns to more frequent characters. Character frequency analysis is the first step in building a Huffman tree.

If 'e' appears 30% of the time, assign it a 2-bit code.
If 'z' appears 0.07% of the time, assign it a 12-bit code.
Overall file size decreases because frequent characters take fewer bits.

Code style analysis - Analyzing character frequencies in a codebase can reveal patterns like excessive use of nested ternary operators (high ? and : frequency) or long variable names (high character-to-word ratio).

Accessibility Improvements

This update includes several accessibility changes that improve the experience for users who rely on screen readers and keyboard navigation.

ARIA Labels on Interactive Elements

ARIA (Accessible Rich Internet Applications) labels provide text descriptions for interactive elements that do not have visible text. Examples:

<!-- Icon-only button without ARIA - screen reader says "button" -->
<button>
  <svg><!-- heart icon --></svg>
</button>

<!-- With ARIA - screen reader says "Add to favorites" -->
<button aria-label="Add to favorites">
  <svg aria-hidden="true"><!-- heart icon --></svg>
</button>

The aria-hidden="true" attribute on the SVG tells screen readers to skip the icon's content entirely. Without it, screen readers might attempt to read the SVG paths and announce meaningless data.

Marking Decorative Elements

Purely decorative elements that add no informational content should be hidden from screen readers:

<!-- Decorative background pattern - skip it -->
<div class="decorative-bg" aria-hidden="true" role="presentation"></div>

<!-- Decorative separator line -->
<hr aria-hidden="true">

<!-- Repeated icon that duplicates adjacent text -->
<button>
  <svg aria-hidden="true"><!-- checkmark --></svg>
  Save Changes
</button>

The Lighthouse Accessibility Score

Google Lighthouse audits web pages across five categories: Performance, Accessibility, Best Practices, SEO, and Progressive Web App. The accessibility score is calculated from automated tests across dozens of checks.

Key automated checks:

A Lighthouse accessibility score of 95+ is achievable and worthwhile. It does not guarantee full WCAG 2.1 compliance (many accessibility requirements are not automatable), but it catches the most common issues that affect the largest number of users.

Summary

Ten tools in a single update brings the total to 46. Here is a quick reference:

All 46 tools are free, require no signup, and process your data entirely in the browser at toolbox-kit.com.