I Built 50 Free Online Tools (All Client-Side, No API Keys, No Tracking)

I got tired of every "free" tool site demanding my email, installing cookies, or hitting rate limits. So I built 50 browser-based tools that run 100% client-side — no server calls, no accounts, no tracking.

The Tools

All tools are pure HTML/CSS/JS, run entirely in your browser, and work offline:

Calculators:

• Percentage Calculator — percentage of, percentage change, percentage difference
• BMI Calculator — with WHO classifications
• Age Calculator — exact age in years/months/days
• Loan Calculator — with amortization schedule
• Mortgage Calculator — monthly payment + total interest
• Compound Interest Calculator — with contribution scheduling
• Calorie Calculator — TDEE + macros (Mifflin-St Jeor)
• GPA Calculator — weighted 4.0 scale
• Fuel Cost Calculator — trip cost estimator
• Discount Calculator — original price, discount %, savings
• Sales Tax Calculator — pre-tax + total
• Tip Calculator — split bill with custom tip %
• Work Hours Calculator — hours worked + overtime
• Date Calculator — days between dates, add/subtract days

Developer Tools:

• JSON Formatter — beautify/minify JSON
• Regex Tester — live highlighting + cheatsheet
• Base64 Encoder/Decoder
• URL Encoder/Decoder
• Hash Generator — MD5, SHA-1, SHA-256, SHA-512
• CSS Minifier — minify + beautify
• Markdown to HTML — live preview
• Text Diff — side-by-side comparison
• PX to REM Converter
• Number Base Converter — binary/octal/decimal/hex
• Text to Binary
• Word Counter — characters, words, sentences, paragraphs
• Case Converter — camelCase, snake_case, UPPER, Title
• Text Wrap/Unwrap
• Email Extractor — deduplicate + sort

Everyday Tools:

• Image Resizer — canvas-based, no upload
• Color Palette Generator — 5-color schemes from a base color
• Color Converter — HEX/RGB/HSL
• Password Generator — customizable length/chars
• Password Strength Checker — entropy + time to crack
• QR Code Generator
• Random Number Generator — range, allow duplicates
• Time Zone Converter — live world clock + meeting planner
• Countdown Timer — event countdowns
• Online Stopwatch — lap timer
• Typing Speed Test — WPM + accuracy
• Internet Speed Test — download speed via CDN
• IP Address Lookup — geolocation + ISP
• ZIP Code Lookup
• Unix Timestamp Converter
• Text to Speech — Web Speech API
• Currency Converter — with live exchange rates
• Aspect Ratio Calculator — width/height from ratio
• Lorem Ipsum Generator
• Unit Converter — length, weight, temperature, volume
• Word Unscrambler

Why No Server-Side Processing?

Every tool runs 100% in your browser. This means:

• Privacy: Your data never leaves your device
• Speed: Instant results, no network latency
• Reliability: Works offline, no server downtime
• No rate limits: Use as much as you want
• No accounts: Just open and use

Tech Stack

• Pure HTML5 + CSS3 + Vanilla JavaScript
• GitHub Pages for hosting (free)
• Zero dependencies, zero frameworks
• Total size: under 500KB across all 50 tools

Try It Out

👉 ToolNest — 50 Free Online Tools

All open source on GitHub. PRs welcome!

What's Next

Planning to add: PDF tools (merge, split, compress), video converter, screenshot tool, and more calculators. Let me know what tools you'd like to see!