43 free browser tools that work offline — the full list

Virginia — Thu, 25 Jun 2026 12:03:03 +0000

I built Utilivise — a hub of 43 utility tools that run 100% in your browser. No account, no sign-up, nothing ever sent to a server. Works offline after the first load.

## Text & Writing

1. Case Converter & Text Editor
Convert text between UPPERCASE, lowercase, Title Case, Sentence case, URL slug, camelCase, and snake_case instantly. Live word and character counts included with one-click copy.

2. Word Scrambler & Anagram Solver
Unscramble letters to find every word you can make from them, solve anagrams, or shuffle a word for fun. Uses a tech, Scrabble, or common-word dictionary — all offline.

3. Client-Side Diff Checker
Paste two blocks of text and instantly see what changed — added lines in green, removed in red, unchanged lines in place. Nothing leaves your browser.

4. Lorem Ipsum Generator
Generate words, sentences, or paragraphs of classic Lorem Ipsum filler text with a single click. Customizable output, no ads, no watermarks.

5. Word Counter & Keyword Density Analyzer
Count words, characters, sentences, and paragraphs as you type. Get reading and speaking time estimates plus your top keywords by frequency and density — useful for SEO.

6. Markdown Table Generator
Build a table in a visual grid and export it as clean GitHub-flavored Markdown or an HTML table. Add/delete rows and columns, set alignment per column, or import a CSV.

7. Find & Replace with Regex
Run powerful find-and-replace over any block of text — literal or full regex with flags, capture-group references, a live highlighted preview, and a match count.

8. Text Sorter & Deduplicator
Sort lines alphabetically, numerically, by length or natural order, remove duplicates, trim whitespace, reverse, shuffle, change case, and number lines — all in one place.

## Developer & Code

9. JSON Formatter & Validator
Beautify, minify, and validate JSON with live error reporting that pinpoints the exact line and column. Includes a collapsible tree view for navigating large documents.

10. Interactive Regex Tester & Explainer
Test a regular expression against your text and see every match live. Get a plain-English breakdown of what each part of the pattern does — with JavaScript flag toggles.

11. Base64 Encoder & Decoder
Encode text to Base64 or decode it back to plain text instantly. One-click copy, no page reloads, no data sent anywhere.

12. Cryptographic Hash Generator
Compute MD5, SHA-1, and SHA-256 hashes from any text instantly in your browser — ideal for checksums and file-integrity verification.

13. QR Code Generator
Create free QR codes for a URL, plain text, WiFi network, or contact card. Pick your colors, then download a high-resolution PNG or copy the SVG. No watermark, no account.

14. Password Generator & Strength Tester
Generate cryptographically secure passwords locally on your device with customizable parameters. Paired with a real-time strength meter — nothing ever leaves the browser.

15. Cron Expression Builder & Explainer
Translate any 5-field cron schedule into plain English, validate it, and see the next five times it will actually run. Essential for anyone writing scheduled jobs.

16. JWT Decoder & Inspector
Paste a JSON Web Token to decode its header and payload, pretty-print the claims, check expiry, and optionally verify the signature (HMAC or RSA/EC) — all locally.

17. UUID & ULID Bulk Generator
Generate UUID v4s or ULIDs in bulk with formatting options, and validate any ID you paste. Backed by cryptographically strong randomness.

18. Equation Solver with Steps
Solve quadratic equations (real or complex roots, discriminant, vertex) and 2-variable linear systems — with the working shown, not just the answer.

## Design & Math

19. Aspect Ratio & Image Calculator
Compute matching dimensions and pixel sizes for any aspect ratio, scaled to your target width or height. Useful for responsive design and video production.

20. Color Palette & Contrast Checker
Generate a harmonious color palette from any base color. Copy as CSS variables, a Tailwind block, or hex. Download a PNG swatch sheet and check WCAG contrast for accessibility.

21. CSS Shadow & Border Visual Designer
Visually design box shadows and border radius with a live preview and copy-ready CSS output. No more guessing values by hand.

22. Scientific Expression Calculator
Type a full math expression — parentheses, powers, roots, trig, logs, factorials, and constants — and get the answer instantly with a reusable history of past calculations.

23. Statistics Calculator
Paste a set of numbers to get a full descriptive-statistics summary — mean, median, mode, standard deviation, quartiles, outliers — plus a distribution histogram.

24. Matrix Calculator
Add, subtract, multiply, scale, transpose, and compute the determinant, inverse, and rank of small matrices — with clear errors when an operation is undefined.

25. Fraction & Ratio Calculator
Add, subtract, multiply, and divide fractions with automatic simplification. Convert between fractions, decimals, and percents, and scale ratios to any term.

## Financial

26. Compound Interest Growth Planner
Project how savings grow over time — set an initial deposit, monthly contributions, return rate, and timespan to see the long-term total and how much of it is interest.

27. Discount & Sales Tax Calculator
Calculate discounted prices, sales tax, and your total savings instantly. Simple, fast, no clutter.

28. Loan & Mortgage Amortization Estimator
Calculate the monthly payment on a mortgage or car loan, see total interest over the term, and get a full year-by-year amortization schedule you can download as CSV.

29. Tip & Group Bill Splitter
Split a restaurant or travel bill among any number of people with a custom tip percentage. Each person's share calculated instantly.

30. Inflation & Salary Calculator
See what a dollar from one year is worth in another, check whether a raise beat inflation, and project a future value at an assumed rate — using a bundled offline US CPI table (1913–present).

31. Paycheck & Salary Converter
Convert pay between hourly, weekly, monthly, and yearly — factoring weekly hours and overtime — and estimate take-home using a deduction percentage you control.

32. Mortgage Affordability Calculator
Work out how much house you can afford — backwards from your income, debts, down payment, rate, and target debt-to-income ratio to a maximum home price and monthly payment.

33. Refinance Break-Even Calculator
See whether refinancing pays off: compare your current mortgage to a new rate and term, with monthly savings, the break-even month on closing costs, and lifetime interest difference.

34. Rent vs. Buy Calculator
Compare the multi-year financial outcome of renting versus buying — including home equity, appreciation, all carrying costs, rent growth, and the opportunity cost of your down payment.

35. Static Ad Revenue Estimator
Estimate monthly and yearly ad revenue from your pageviews and a target RPM. Useful for content creators and publishers planning monetization.

## Date & Time

36. Age & Date Calculator
Find an exact age from a birthday in years, months, and days. Calculate the duration between two dates, or add and subtract days, weeks, months, and years from any date.

37. Time Zone Converter & Meeting Planner
Convert a time across multiple cities at once and instantly see the overlapping working hours. The sane way to schedule a meeting across the globe.

38. Countdown & Days-Until Timer
A live ticking countdown to any date and time — with a business-days count and a shareable link that reopens the exact countdown for anyone you send it to.

39. Stopwatch & Pomodoro Timer
A precise drift-free stopwatch with laps, plus a configurable Pomodoro focus timer with work/break cycles and an end-of-phase chime.

## Calculators

40. Unit Converter
Convert between units of length, mass, volume, area, speed, time, digital storage, pressure, energy, and temperature — instantly and fully offline.

41. Percentage Calculator
Solve the three everyday percentage questions: what is X% of Y, X is what percent of Y, and the percentage change between two numbers.

42. BMI & Body Metrics Calculator
Calculate Body Mass Index with a visual category scale, plus your BMR and estimated daily maintenance calories by activity level — metric or imperial.

43. Random Picker & Decision Maker
Flip a coin, roll dice, draw a random number, pick winners from a list, or split names into fair teams — all using cryptographically strong randomness.

## Why I built it this way

Most online tool sites send your data to a server. That means your JSON, your passwords, your JWT tokens, and your salary numbers all hit someone else's infrastructure.

Utilivise runs entirely in the browser. Every tool is a self-contained React component — no fetch calls, no backend. Built with React 19 + Vite, prerendered to static HTML at build time for fast loads and SEO, deployed on Vercel.

Every tool has its own bookmarkable URL (/tools/json-formatter, /tools/qr-generator, etc.) so you can link directly to what you use.

Would love feedback on tools you'd want added.

DEV Community: Virginia

43 free browser tools that work offline — the full list