Free online calculators
Calculator categories
Construction calculators
Concrete, paint, tiles, roof pitch and mortar. Volume and waste on separate pages.
Mathematics calculators
GCD, circle area, percent, volumes and sequences. Each formula on its own page.
Physics calculators
Mechanics, current, waves and heat. Each formula has its own page.
Health calculators
BMR, TDEE, water and protein. Formula numbers, not a diagnosis.
Finance calculators
Deposit, VAT, loan payment and inflation. Each formula stays on its own page.
Motoring calculators
Fuel use, TCO and leasing. Car costs on separate pages.
Salary calculators
Gross, net and leave. Contributions live on separate pages.
Unit converters
Kilometers, gallons, bars and feet. SI, US and UK definitions stay separate.
Cooking calculators
Cups, portions and alcohol. Kitchen conversions, not a diet plan.
Business calculators
Margin, markup and break-even. Accounting formulas, not a company valuation.
Date and time
Date difference, age and countdown. Calendar math, not time zones.
Music calculators
BPM, cents, intervals and frequencies. Each conversion has its own page.
Lifestyle
Commute, subscriptions and office days. Cost estimates, not life advice.
Esoteric
Zodiac, numbers and biorhythms. Date and name tools, not fortune telling.
IT calculators
Network, storage and developer tools. Each formula on its own page.
Real estate calculators
Area, price per square metre and home loans. Formulas on separate pages.
Ecology calculators
Carbon footprint and energy. Estimates, not a certificate.
Agentic commerce
Agent and autonomous-transaction costs. Estimates, not legal advice.
Biometrics and prevention
Screening and risk from formulas. Not a diagnosis.
AI regulation
Compliance, risk and the AI Act. Estimates, not legal advice.
Popular calculators
Most used free online calculators - no signup:
Calculator categories - overview
| Category | Example calculators |
|---|---|
| Construction calculators | paint, concrete, tiles |
| Mathematics calculators | GCD, circle area, percent |
| Physics calculators | pressure, Ohm, heat |
| Health calculators | BMR, TDEE, water |
| Finance calculators | deposit, VAT, loan payment |
| Motoring calculators | fuel use, TCO, trip cost |
| Salary calculators | gross, net, leave |
| Unit converters | km, miles, temperature |
| Cooking calculators | cups, recipe scaling |
| Business calculators | margin, markup, break-even |
| Date and time | age, date difference |
| Music calculators | BPM, intervals |
| Lifestyle | commute, subscriptions |
| Esoteric | zodiac, numbers |
| IT calculators | network, storage |
| Real estate calculators | area, mortgage |
| Ecology calculators | footprint, energy |
| Agentic commerce | agents, GMV |
| Biometrics and prevention | screening, risk |
| AI regulation | AI Act, compliance |
- 723 free calculators in 20 categories: construction, mathematics, physics, finance and health.
- Currency and unit settings from the header stay consistent across the site.
- Methodology, sources, and FAQ: About CalcBoxer