JSON Formatter
Format, validate & minify JSON online free
Mortgage Calculator
Monthly payment with PMI calculator free
TDEE Calculator
Calculate daily calories free online
Password Generator
Generate secure random passwords free
AI Resume Scanner
Beat ATS systems — find missing keywords
Age Calculator
Exact age in years, months, days
Random Number
Generate random numbers
GPA Calculator
Calculate your GPA
Unit Converter
Temp, weight, length, volume
Coin Flip
Heads or tails?
Dice Roller
Roll d4 through d20
How to Budget Your Money
The complete 50/30/20 guide
How to Calculate Your TDEE
Calories for weight loss or muscle gain
About LifeStack
Our mission and principles
Apr 3, 2026 — Added Typing Speed Test, Compare Mortgages, Compare Job Offers, Everyday tools (Age, Random Number, GPA, Unit Converter, Coin Flip, Dice Roller), Personal Dashboard, AI Resume Scanner, tool chaining, and shareable results. 58+ tools!
Apr 1, 2026 — Added Word Counter, Case Converter, Image to Base64, Pomodoro Timer, Countdown Timer, Git Cheat Sheet, HTTP Status Codes, ASCII Table. Amazon affiliate recommendations on all tools.
Mar 30, 2026 — 🚀 LifeStack launched with 32 free tools across dev, finance, health, and travel.
JSON Formatter
Beautify, minify & validate
Base64
Encode & decode text
UUID Generator
v4 UUIDs, one click copy
Regex Tester
Live pattern matching
JWT Decoder
Decode token payloads
Timestamp
Unix ↔ human date
Color Converter
HEX ↔ RGB ↔ HSL
Text Diff
Compare two text blocks
Hash Generator
SHA-256, SHA-1, SHA-512
URL Encode
Encode & decode URLs
Lorem Ipsum
Generate placeholder text
Password Generator
Secure random passwords
QR Code
Generate QR codes
Markdown Preview
Live markdown rendering
Cron Parser
Explain cron expressions
Git Cheat Sheet
Searchable command reference
HTTP Status Codes
Complete code reference
ASCII Table
Character code lookup
Word Counter
Count words & characters
Case Converter
Upper, lower, title case
Image to Base64
Convert images to data URI
Pomodoro Timer
25-min focus sessions
Countdown Timer
Count down to any date
Compound Interest
Watch your money grow
50/30/20 Budget
Needs, wants, savings
Net Worth
Assets minus liabilities
Paycheck
Estimate take-home pay
Mortgage
Monthly payment calculator
Savings Goal
How much to save monthly
Debt Payoff
Payoff time & interest
Hourly ↔ Salary
Convert pay rates
Compare Mortgages
Side-by-side comparison
Compare Job Offers
Total compensation comparison
Percentage
Quick percentage math
Retirement
Are you on track?
Rent vs Buy
Which saves more?
ROI Calculator
Return on investment
TDEE Calculator
Daily calorie needs
Macros
Protein, carbs & fat
BMI
Body mass index
Water Intake
Daily hydration goal
One-Rep Max
Estimate your 1RM
Body Fat %
Navy method estimate
Caffeine Tracker
When will it wear off?
Sleep Cycles
Best time to fall asleep
Protein Intake
Daily protein target
Running Pace
Pace, speed & splits
Timezones
Convert across cities
Packing List
Generate by trip type
Trip Budget
Estimate travel costs
Currency
Quick exchange rates
Tip Calculator
Split bills easily
About LifeStack Tools
LifeStack Tools is a free collection of 61+ online utilities designed for developers, professionals, students, and anyone who needs quick calculations without signing up for yet another service. Every tool runs entirely in your browser — your data never leaves your device, and there's nothing to install.
Why We Built This
As software engineers, we found ourselves Googling the same tools every day — JSON formatters, regex testers, unit converters, mortgage calculators. Most sites are cluttered with ads, require signups, or upload your data to their servers. We wanted one clean, fast, private place for all of them.
Developer Tools
Our developer toolkit includes 26 tools built for daily coding workflows. The JSON formatter validates and beautifies JSON with syntax error highlighting. The regex tester provides live matching as you type, and our unique Regex-to-English translator explains any pattern in plain language. The JWT decoder reveals token payloads without external services. We also offer Base64 encoding, UUID generation, SHA hashing, URL encoding, a color converter between HEX/RGB/HSL, a text diff checker, and a CSS unit converter for px/rem/em/vw conversions.
Finance Calculators
Our 14 finance calculators help you make smarter money decisions. The compound interest calculator shows how investments grow over decades. The mortgage calculator includes PMI estimation and shows when it drops off. Our unique job offer comparison tool calculates true total compensation including 401(k) match, PTO value, and commute time cost. We also offer retirement planning with the 4% safe withdrawal rule, rent vs buy analysis, debt payoff timelines, and the 50/30/20 budget framework.
Health & Fitness
Our 10 health tools use scientifically-backed formulas. The TDEE calculator uses the Mifflin-St Jeor equation — the most accurate BMR formula according to research. The macro calculator splits calories into protein, carbs, and fat based on your goal (fat loss, maintenance, or muscle gain). The body fat estimator uses the U.S. Navy method requiring only a tape measure. We also offer a caffeine half-life tracker, sleep cycle calculator, protein intake guide, and running pace calculator.
Privacy & Security
Every calculation happens in your browser using JavaScript. We never see your data — not your salary, not your weight, not your resume. There are no accounts, no cookies tracking you across the web, and no data uploaded to any server. Your saved preferences and history are stored in your browser's localStorage, which only you can access.
Works Offline
LifeStack Tools works without an internet connection. After your first visit, all tools are cached locally via a service worker. You can install it as an app on your phone or computer and use it anywhere — on a plane, in a subway, or in areas with poor connectivity.