WebTools is a free collection of 215 calculators that show their working. Each one gives you the answer, explains the method behind it and lets you change any assumption. All calculations run in your browser.
The tools are made for India. Money tools use Indian digit grouping (₹12,34,567) and lakh and crore wording, and cover Indian schemes such as PPF, NPS, SSY and the old and new income tax regimes.
Who WebTools is for
- People planning money decisions, such as projecting SIP returns, comparing a SIP with a lumpsum, checking a home loan EMI or choosing between the old and new tax regimes.
- Students and professionals who need maths, statistics or physics calculators, from fractions and percentages to t-tests and projectile motion.
- Developers who want a quick JSON formatter, JWT decoder, regex tester or cron explainer that runs in the browser.
- Anyone who wants to see the working before trusting a number.
What you can calculate
| Area | Tools | Examples |
|---|---|---|
| Money | 71 | SIP calculator, EMI calculator, income tax calculator, XIRR, PPF, FD, GST, gratuity |
| Maths | 67 | Percentage calculator, scientific calculator, standard deviation, matrix, p-value, projectile motion |
| Everyday | 44 | Age calculator, unit converter, GPA, land area, brick and tile calculators, image compressor, word counter |
| Developer | 20 | JSON formatter, JWT decoder, regex tester, cron explainer, IP subnet calculator, UUID and password generators |
| Health | 13 | BMI calculator, BMR and TDEE, body fat, protein intake, pregnancy and heat index calculators |
Money tools are grouped into investing, savings and retirement schemes, loans, tax, salary and income, real estate and business.
How each calculator is checked
- A written specification first. Each tool starts with a spec that covers its inputs, ranges, formulas and conventions.
- Independent test values. Test values are worked out outside the site’s own code, using at least two methods. A tool whose test values came from the code it tests doesn’t ship.
- Rules that must always hold. Automated property tests check them. For example, the SIP calculator must return the amount invested at a 0% return, and doubling the monthly amount must double the value.
- Primary sources. Formulas are checked against regulators such as SEBI and RBI, official documents or standard textbooks. Each page lists its sources and the date they were last checked.
- Visible corrections. Each page shows its last review date and a changelog. Corrections are logged, never made silently. Money tools are reviewed at least once a year and after relevant regulatory changes.
What the results assume
Results exclude tax, fees, loads and charges unless a tool says otherwise. They assume a steady return, but real returns are uneven and can be negative. Money tools state their currency and round only for display.
The calculators are educational. They are not investment, tax, legal or medical advice.
Frequently asked questions
Are the WebTools calculators free?
Yes. All 215 tools are free.
Where do the calculations run?
WebTools says all calculations run in your browser. For how the site itself handles analytics, see the WebTools privacy page.
How do I know a result is right?
Each calculator explains its method and assumptions, with worked examples and sources you can check. Every tool is also tested against values worked out outside its own code.
What if I find a mistake?
Report it through the WebTools contact page, ideally with the calculator link that includes your inputs. Confirmed errors are fixed, noted with a date in the page’s changelog and covered by a new test so they don’t come back.
Explore WebTools
- Browse all 215 tools on WebTools
- Read how the calculators are checked
- See another project that shows its working: Fitness, an exercise library with sourced cues