All tools

Every tool runs locally in your browser — nothing you enter is uploaded, logged, or stored. Choose a category or use the search ( Ctrl K or / anywhere on the site).

Business Calculators

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Profit Margin Calculator → See profit margin and markup percentages side by side from revenue and cost — with gross profit and rounding you control.

Markup Calculator → Calculate markup percentage, markup amount, and the selling price you need from any cost figure, with a margin cross-check.

Gross Profit Calculator → Calculate gross profit and gross margin from revenue and cost of goods sold, with a target-revenue mode.

Discount Calculator → Calculate the final price after any percentage discount, the exact amount saved, and the discount between two prices.

Break-Even Calculator → Find how many units you must sell — and at what revenue — to cover your fixed costs, from price and variable cost.

Cash Runway Calculator → Estimate how many months your business can operate before running out of cash, from balance, expenses, and income.

Billable Hourly Rate Calculator → Set a freelancer or agency hourly rate that covers your target income, overhead, taxes, and unpaid time.

Payment-Processing Fee Calculator → See exactly what a payment processor takes from a transaction: percentage fee, fixed fee, and what you actually receive.

Loan Amortization Calculator → Compute the monthly payment for any loan and see the full amortization schedule — or enter a payment to find how much you can borrow.

Compound Interest Calculator → Project how an investment grows with compound interest — with optional monthly contributions and yearly, quarterly, monthly, or daily compounding.

Math Calculators & Converters

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Percentage Calculator → Four percentage calculations in one tool: X% of Y, X is what % of Y, % change from X to Y, and Y plus or minus X%.

Unit Converter → Convert length, weight, temperature, volume, and speed between metric and imperial units with exact conversion factors.

Health Calculators

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BMI Calculator → Calculate your Body Mass Index from metric or imperial measurements, with the WHO classification and a healthy weight range.

Home & Construction Estimators

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Paint Calculator → Estimate how many gallons or liters of paint you need for a room, from wall measurements, openings, and coats.

Flooring Calculator → Estimate the flooring boxes you need for a room: area from length and width, waste allowance, pack count, and cost.

Tile Calculator → Estimate the tiles and boxes you need for a floor or wall, with waste, grout, tile size, and total cost.

Concrete Calculator → Estimate concrete volume in cubic yards or meters and the number of bags needed for a slab, footing, or pad, with cost.

Gravel Calculator → Estimate gravel volume in cubic yards or meters, weight in tons, and cost for a driveway, path, or base layer.

Developer Tools

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JSON Formatter & Validator → Format and validate JSON with readable indentation, precise error messages, and byte-size stats — fully local.

JSON Minifier → Compress JSON to its smallest valid form — strip all whitespace, count the bytes saved, and copy or download.

CSV to JSON Converter → Convert CSV files and pasted tables into JSON objects with automatic delimiter detection and header mapping.

JSON to CSV Converter → Convert a JSON array of objects into RFC 4180 CSV with correct quoting, column union, and copy or download.

Base64 Encoder & Decoder → Encode text or files to Base64 and decode back, with UTF-8 handling, validation, and size stats — fully local.

AI Token Counter → Estimate tokens and API cost for any prompt across GPT-4o, Claude Sonnet 4, and other models — fully local.

Regex Tester → Test regular expressions live against your own text with match highlighting, capture groups, and flags — fully local.

Text Diff Checker → Compare two blocks of text line by line with added, removed, and unchanged highlighting plus change statistics — fully local.

Unix Timestamp Converter → Convert between Unix seconds, Unix milliseconds, ISO 8601, and human-readable local time — live, fully local.

UUID Generator → Generate RFC 4122 version-4 UUIDs from cryptographically secure randomness — one at a time or in bulk, fully local.

URL Encoder / Decoder → Encode or decode text for safe use in URLs with percent-encoding — instant, fully local, and faithful to the browser.

Hex to RGB Converter → Convert hex color codes to RGB triplets and back — instantly, with 3- and 6-digit shorthand support, fully local.

Number Base Converter → Convert integers between binary, octal, decimal, and hexadecimal with exact BigInt arithmetic — no rounding, fully local.

Data Size Converter → Convert between bits and bytes — KB, MB, GB, TB, PB — with decimal (SI) precision, exact arithmetic, fully local.

Password Generator → Generate strong passwords locally with cryptographically secure randomness — unbiased sampling, class guarantees, zero uploads.

Hash Generator → Generate SHA-1, SHA-256, SHA-384, and SHA-512 hashes locally with WebCrypto — hex and base64 output, nothing uploaded.

JWT Decoder → Decode JWT header, payload, and claims locally — with optional HMAC signature verification. Nothing leaves your browser.

Cron Builder → Build and validate five-field cron expressions with a human-readable description and honest next-run times.

Time & Date Tools

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Date Difference Calculator → Calculate the exact number of days, weeks, months, and years between two dates — with a single trusted method.

Business Days Calculator → Count business days between dates or add business days to a date — weekends and your own holidays excluded.

Time Zone Converter → Convert any date and time between IANA time zones with correct daylight-saving handling and explicit offsets.

Meeting Overlap Planner → Find the time windows when teams in different time zones can meet, using their local work hours and DST-aware math.

Age Calculator → Calculate exact age in years, months, and days, plus total days lived and the days until your next birthday.

Image Tools

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Image Resizer → Resize JPG, PNG, WebP, and GIF images to any maximum dimension, preserving aspect ratio — on your device.

Image Compressor → Compress JPG and WebP images with a quality slider, live size savings and dimensions, processed fully on your device.

JPG, PNG & WebP Converter → Convert images between JPG, PNG, and WebP with a quality control — locally, with live size and dimension stats.