Launched this week

Calculator Castle

Launched this week

242 free calculators, no signup, answer in one screen

4 followers

242 free calculators, no signup, answer in one screen

4 followers

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Financial planning

242 free online calculators for money, health, math, and everyday life. No account, no clutter, and most show the formula.

Free

Launch tags:Health & Fitness•Education•Finance

Launch Team / Built With

Zendesk for StartupsUp to 2 years free for startups + AI Agents & Copilot

Promoted

Maker

📌

I built this because every calculator site I landed on gave me the same experience: the answer buried under three ad blocks, a cookie wall, and a prompt to sign up before it would show me the result. 242 calculators now. The ones I like best are the boring specific ones — Army body fat, GFR, Weight Watchers points, voltage drop, stair rise and run. Things where people currently open a PDF chart or a forum post from 2011. Most of them show their working rather than just a number. The mortgage one gives the full amortisation table. The BMI one uses the CDC percentile charts for children instead of pretending the adult formula applies to a 7 year old. Nine of them embed on your own site with one line of HTML, if you run something where a working calculator would help. It went up recently and I am still filling gaps, so the useful thing you can tell me is which calculator you came looking for and could not find. That is what I build next.

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2d ago