Free online calculators and converters
Get a clear answer in seconds, then see the formula and a worked example so you can trust it. Built for India and the US, with no sign-up.
- Formula shown on every page
- Worked examples for India and US
- Runs in your browser, nothing stored
Browse calculators by category
- BiologyCalculators for lab work, genetics, animal gestation and pet care, built on standard biological formulas.Coming soon
- ChemistryCalculators for molarity, stoichiometry, gas laws and other lab chemistry, with units shown at every step.Coming soon
- ConstructionMaterial, area and cost estimators for building, concrete, flooring and renovation, in metric and imperial units.1 tool
- ConversionUnit converters with the exact formula and a quick-reference chart for length, weight, volume, speed and more.1190 tools
- EcologyFootprint and energy calculators that show how everyday choices affect the environment.Coming soon
- Everyday LifeHandy calculators for dates, shopping, travel, home and daily planning.1 tool
- FinanceLoan, investment, tax and savings calculators with India and US examples and clear formulas.3 tools
- FoodCooking, recipe-scaling and nutrition calculators with metric and US measures.Coming soon
- HealthBody, fitness and wellness calculators with reference ranges and plain-language guidance.1 tool
- MathStep-by-step math calculators for algebra, geometry, trigonometry and number work.1 tool
- OtherUseful specialist calculators that do not fit another category.Coming soon
- PhysicsPhysics and engineering calculators with SI units, formulas and worked examples.1 tool
- SportsTraining, performance and scoring calculators for runners, cyclists, lifters and team sports.Coming soon
- StatisticsStatistics calculators for averages, spread, probability, tests and confidence intervals.1 tool
Start with these calculators
- ROI Calculator
Finance - EMI Calculator
Finance - Compound Interest Calculator
Finance - BMI Calculator
Health - Percentage Calculator
Math - Standard Deviation Calculator
Statistics - Ohm’s Law Calculator
Physics - Concrete Calculator
Construction - Age Calculator
Everyday Life - Radiation Dose Equivalent Converter
Conversion - Typography Converter
Conversion - Magnetic Field Strength Converter
Conversion
How ToolsVault makes answers you can trust
Answer first
Each page opens with a short answer and a real example, then gives you the calculator so you can use your own numbers.
Show the working
You see the formula, what each symbol means and a step-by-step example, so you can check the result by hand.
Checked before it goes live
We recompute the worked examples independently and publish a tool only when its formula and checks are complete.
Frequently asked questions
Are ToolsVault calculators free?
Yes. Every calculator and converter is free to use with no sign-up. You can use them as often as you like.
Do you store the numbers I enter?
No. Calculations run in your browser using the formula shown on the page. The values you type are not sent to our servers.
How do you check that the answers are correct?
Each tool shows its formula and worked examples, and we recompute those examples independently before a page goes live. We publish a calculator only when its formula, examples and checks are complete.
Do the calculators work for India and the US?
Yes. Where it matters, tools use Indian or international number formats and show examples for both markets, such as rupees and lakh for India and dollars for the US.
Why are some categories still small?
We add calculators in waves and publish each one only when it is ready, so a category grows as its tools pass checks. Browse the site map to see everything that is live.
1199 tools live. See the full site map · Edited by Hemant Kumar and Anjita Rai, founders of ToolsVault.