Tools that respect your data.

Paste any JSON to instantly beautify, validate, or minify it — 100% client-side, so your data never leaves your browser.

Encode text to Base64 or decode any Base64 string in your browser — no uploads, no server, no tracking.

Generate cryptographically random UUID v4 values in your browser — no server involved, no data sent anywhere.

Percent-encode text for safe use in URLs, or decode encoded strings back to plain text — entirely in your browser, with no data sent to any server.

Paste any JSON Web Token to instantly decode its header, payload, and claims — all client-side, so your token never leaves your browser.

Compute SHA-256, SHA-512, SHA-1, and SHA-384 hashes instantly in your browser — your text never leaves your device.

Convert epoch seconds or milliseconds to readable dates — and back — entirely in your browser.

Convert HEX, RGB, HSL, and CMYK in real time — 100% client-side, your colors never leave your browser.

Paste a cron expression and see exactly what it means — plus the next 10 scheduled run times in UTC and your local timezone. 100% client-side, nothing leaves your browser.

Bidirectional conversion between JSON and YAML — runs entirely in your browser, so your data never leaves your machine.

Create scan codes for URLs, WiFi, text, or contacts — entirely in your browser, with no data uploaded to any server.

Test JavaScript regular expressions in real time — live highlighting, full capture-group inspection, and instant flag toggling, all 100% client-side.

Type in any base — binary, octal, decimal, or hex — and all four update instantly, client-side with no data sent anywhere.

Estimate LLM tokens across GPT-4o, Claude, Gemini, and Llama instantly — no API key, no server, no data upload.

Generate accurate TypeScript interfaces from any JSON sample — entirely in your browser, with no data sent to a server.

Count words, characters, sentences, and reading time in real time — 100% client-side, no uploads, no tracking.

Real-time character, codepoint, and byte counts — fully Unicode-aware, 100% client-side so your text never leaves your browser.

Convert any text between 11 naming cases instantly — runs entirely in your browser, no data ever sent to a server.

Create strong, random passwords instantly — 100% client-side, so the password never leaves your browser.

Create realistic filler text in seconds — paragraphs, sentences, or words — entirely in your browser, with no data sent anywhere.

Remove duplicates from any list in seconds — order preserved, 100% client-side, nothing leaves your browser.

Compare two texts line-by-line in your browser — nothing is uploaded, stored, or logged.

Reverse any text by characters, words, or lines — emoji and accents survive intact, and your data never leaves your browser.

Encode special characters to HTML entities or decode them back to plain text — fully client-side, nothing leaves your browser.

Render Markdown to HTML live in a split-view editor — your content never leaves your browser.

Turn any text into a clean, URL-safe slug — accent transliteration, configurable separator, and max length, all processed in your browser.

Convert numbers to Roman numerals (and back) with a full additive/subtractive breakdown — entirely in your browser, no data sent anywhere.

Four percentage modes in one tool — results and formulas shown instantly, 100% in your browser.

Count days between dates or shift a date forward and back — pure UTC arithmetic, no server, no tracking.

Enter a birthdate and get your exact age in years, months, and days — 100% client-side, no data ever leaves your browser.

Compute your body mass index from height and weight — metric or imperial — with WHO categories shown inline. Your data never leaves your browser.

Add or subtract durations, or find the gap between two clock times — results in HH:MM:SS, human-readable, ISO 8601, and total seconds, all client-side.

Compute tip, total, and per-person split in seconds — all math runs in your browser, nothing is sent to a server.

Instant monthly payment, total interest, and amortization schedule — 100% client-side, your numbers never leave your browser.

Estimate investment growth with configurable compounding frequency and periodic contributions — all calculations run in your browser, no data ever sent anywhere.

Find your total daily energy expenditure, maintenance calories, and macro targets — all calculated in your browser with no data sent anywhere.

Find your return on investment, annualized CAGR, and profit or loss instantly — all calculated locally in your browser, with no data sent anywhere.

Enter a start value, end value, and holding period to get compound annual growth rate, total return, and estimated doubling time — all computed locally in your browser.

Compare your current loan to a refinanced mortgage and get your break-even month, monthly savings, and lifetime interest difference — all computed locally in your browser.

See your projected balance in both future dollars and inflation-adjusted today's dollars — plus a sustainable monthly income estimate — with no data ever leaving your browser.

Find the final price after any percentage or fixed discount — including stacked promos, sales tax, and multi-item quantities — without sending your data anywhere.

Enter any length value and see all eight unit conversions at once — metric and imperial — without re-running the calculation.

Enter any temperature value and get °C, °F, and Kelvin simultaneously — with a contextual marker that tells you exactly where your value falls on the scale.

Enter any weight value and see all 7 unit conversions at once — including stone — with no data ever leaving your browser.

Compute any base to any power instantly — with step-by-step expansion and scientific notation — entirely in your browser, no data sent anywhere.

Calculate fractions, mixed numbers, and decimals with full step-by-step work — 100% client-side, no data ever leaves your browser.

Build a personalized payoff plan for every debt you carry — snowball or avalanche — with no signup and no data ever leaving your browser.

Get your personalized macronutrient targets for cut, maintain, and bulk goals — calculated entirely in your browser, with no data sent anywhere.

Estimate your body fat %, lean body mass, and fat mass using the U.S. Navy formula — all calculations run in your browser, no data ever sent to a server.

Estimate calorie expenditure for 24 activities using the Ainsworth Compendium MET formula — 100% client-side, no data sent anywhere.

Enter your loan details and an extra payment amount to see your new payoff date, total interest saved, and full amortization comparison — all calculated in your browser.

Compute gross, operating, and net margin side-by-side — or back-solve the price you need from a target margin or markup. Runs entirely in your browser.

Get your full loan amortization schedule — monthly payment, total interest, and a downloadable CSV — all computed locally in your browser.

Estimate kidney function using the CKD-EPI 2021 race-free equation — your data stays in your browser, never sent to a server.

Convert HbA1c to estimated average glucose — or eAG back to A1C — instantly in your browser, with no data ever sent to a server.

Figure out your conception date — and due date — from three reference points, with cycle-length adjustment and trimester-calibrated uncertainty ranges.

Enter any race distance and target time to get your pace per km and mile, a full 5K split schedule, and Riegel-predicted finishing times — all computed in your browser, nothing sent anywhere.

Enter your embryo transfer date and stage to get your estimated due date, equivalent LMP, and current gestational age — calculated entirely in your browser.

See your payoff date and how extra payments cut months and interest — calculated entirely in your browser.

Enter your AIME and birth year to see your estimated monthly benefit at every claim age from 62 to 70 — no account required, no data ever leaves your browser.

Project your retirement balance with accurate employer-match modeling — 100% client-side, your data never leaves your browser.

Calculate your monthly auto payment, total interest, and exact financed amount — including state-specific trade-in tax credits. Runs entirely in your browser.

Compare three payoff strategies side by side — minimum payment, fixed amount, or a target date — with all math running locally in your browser.

Enter the breeding date and breed size to get the estimated whelping date, current gestational stage, and a live countdown — all calculated privately in your browser.

Enter your lipid panel values to instantly calculate all three cardiovascular ratios and non-HDL cholesterol — no account, no data uploads, everything stays in your browser.

Compare two fixed-rate mortgage offers side-by-side — monthly payment, lifetime cost, and the exact month one deal beats the other — entirely in your browser.

Predict your fertile window and ovulation date for up to 6 cycles — 100% client-side, no data leaves your browser.

Total calories and macros for any meal in seconds — 100% client-side, your data never leaves your browser.

Instantly convert between nominal APR and effective APY for any compounding frequency — all calculations run in your browser, no data sent anywhere.

Compute cap rate, annual NOI, or property value from any two inputs — all three modes in one tool, with a built-in NOI builder. Your numbers never leave your browser.

Estimate dividend income, yield, and reinvestment growth instantly — all calculations run in your browser, so your data never leaves your device.

Enter your goal time or current pace to get split targets, finish time estimates, and race predictions — all computed in your browser, nothing sent anywhere.

Get your target pace, split chart, and finish time estimate — all computed in your browser with no data ever sent to a server.

Estimate glomerular filtration rate from serum creatinine using CKD-EPI and MDRD — all calculations run locally in your browser, no data ever uploaded.

Find your cycling pace, average speed, or finish time instantly — all computed in your browser with no data sent anywhere.

Determine heart rate from any ECG strip instantly — large box, small box, or 6-second method — with no data leaving your browser.

Figure out your credit card interest, payoff timeline, and total cost — instantly, with no data ever leaving your browser.

Break down agent commission splits instantly — all math runs in your browser, no data sent anywhere.

Find out exactly how much you owe each month, how long it takes to pay off, and how much interest you'll pay — all calculated privately in your browser.

See the real difference between a stated dividend rate and APY — all calculations run in your browser, no data sent anywhere.

Calculate body mass index for adolescents using CDC age- and sex-specific percentile charts — all processing happens in your browser, nothing is sent to any server.

Get trimester-by-trimester weight gain ranges based on your pre-pregnancy BMI — all calculated in your browser, no data sent anywhere.

Instantly estimate Missouri state and local sales tax on any purchase — runs entirely in your browser, no data sent anywhere.

Compute state and local sales tax on any purchase — 100% client-side, no data leaves your browser.

Compute Alabama state and local sales tax instantly — all calculations run in your browser, no data ever sent to a server.

Instantly calculate Florida state sales tax (6%) plus your county's discretionary surtax — all in your browser, with no data sent anywhere.

Estimate calories burned during any workout using your heart rate and personal stats — all computed in your browser, no data ever sent anywhere.

Compute the fair value of a fixed-coupon bond from face value, coupon rate, yield to maturity, and years to maturity — 100% client-side, no data ever leaves your browser.