Calculators that respect your time.
Calchy is built by a single person — Yiannis Dimas, founder of DMS Tuned, an automotive performance shop in Athens, Greece, and Vroum.gr, a Greek automotive directory.
Why this exists
Every time I needed to convert PSI to bar for a customer’s tire pressure, or check what the OEM cold spec was for a 2019 VW Tiguan, I ended up on a page with three pop-ups, two cookie banners, an interstitial ad, and a calculator that loaded after eight seconds.
Calchy is the version I wanted. Type a number, get the answer. Big number, small unit, formula below. No signup. No newsletter. No “sign in to save your result”.
What’s here
- Automotive: tire pressure (every make, model, year), boost-to-HP, gearing, power-to-weight, tire size compare
- Money: loan + amortization, compound interest, credit card payoff, tip, discount, paycheck
- Conversions: PSI/HP/MPH/Nm/L/°C/kg/cm/km — with reference tables for nearby values
- Health: BMI, body fat, BMR, TDEE, macros
- Home: paint, concrete, tile coverage
- ~1,000 instant-answer pages at /answers/[exact question] — for people who type their question into Google verbatim
How the data is sourced
Tire pressure specs come from manufacturer door-jamb stickers and owner’s manuals — the same source dealerships and shops use. Conversion factors are SI-canonical (PSI×0.0689476 = bar, etc.). Loan amortization uses the standard formula P × r × (1+r)^n / ((1+r)^n − 1). BMI uses the WHO classification thresholds. TDEE uses Mifflin-St Jeor with standard activity multipliers.
If you spot a number that’s wrong, ping me — I read everything via the suggestion form on the homepage.
The author
Yiannis Dimas. Tuner-shop owner since 2013 (DMS Tuned) — Mazda MX-5, BMW, VW dyno tuning, ECU remaps, swaps. The reason tire pressure is over-built on this site is because it’s the calc I personally need most.
Reach me at yiannis@dmstuned.eu or via the suggestion form.