The answer, measured. Free online tools that just work.

Calculators and converters for real jobs — reading shift times, ordering gravel, checking your PTO. No sign-up, nothing uploaded, every formula shown.

Money & Work

VAT Calculator

Add or remove VAT at any rate — see net, tax, and gross instantly.

PTO Accrual Calculator

See how much paid time off you've earned and when you'll reach your goal.

Construction & DIY

Gravel Calculator

Work out how many tons or cubic yards of gravel your project needs.

Concrete Calculator

Slabs, footings, and columns — get cubic yards and how many bags to buy.

Roof Pitch Calculator

Convert rise and run to pitch, angle, and rafter length in one step.

Time & Date

Military Time Converter

Convert between military (24-hour) time and standard AM/PM time instantly.

Chronological Age Calculator

Exact age in years, months, and days between two dates — test-day accurate.

Health & Fitness

Sleep Cycle Calculator

Find the best time to fall asleep or wake up based on 90-minute cycles.

Running Pace Calculator

Pace, finish time, or distance — solve any one from the other two.

Generators

Wedding Hashtag Generator

Turn your names and wedding date into dozens of hashtag ideas — free.

Games & Hobbies

Riichi Mahjong Score Calculator

Han, fu, dealer or not — get the exact payout without the score table.

Why HatchCalc

Every tool here runs directly in your browser — nothing you type is ever uploaded to a server. That makes the tools fast, private, and available even on a flaky connection once the page has loaded.

No accounts, no paywalls, no "free trial". Each tool also explains the exact formula or method behind it, so you can trust (and verify) the results.