Free online calculators
88 calculators for money, maths, health, conversions and everyday life. Each one shows its formula. No sign-up.
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Unit & currency converterNumber to wordsRoman numeralsNumber basesFraction to decimal
Popular calculators
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Everyday
Maths & statistics
- Triangle calculator (three sides)
- Right triangle and Pythagorean theorem calculator
- Circle calculator: area, circumference and diameter
- Quadratic equation solver
- Slope calculator: slope, distance and midpoint
- Logarithm calculator (any base)
- Exponent calculator (powers)
- Root calculator: square, cube and nth roots
- GCF and LCM calculator
- Prime factorisation calculator
- Rounding calculator
- Scientific notation converter
- Percent error calculator
- Ratio calculator (A : B = C : D)
- Permutation and combination calculator (nPr, nCr)
- Z-score calculator with percentile
- Probability calculator for two independent events
- Sample size calculator for surveys
- Confidence interval calculator for a mean
- Half-life calculator
Money & business
- Compound interest
- Loan payment
- Savings goal
- Inflation & purchasing power
- Salary to hourly pay
- Profit margin & markup
- Break-even units
- VAT / sales tax
- Website ad revenue
- Subscription cost & waste
- Small habit lifetime cost
- Real hourly rate
- Rent vs buy
- Mortgage calculator
- EMI calculator
- SIP calculator
- GST calculator (India)
- Freelance quote & project profit
- Marketplace profit & selling price
- Mortgage refinancing break-even
- Weekly budget calculator
- Monthly budget calculator
Tax & salary
- UK salary after tax calculator 2026/27
- US salary after tax calculator (2026)
- India salary after tax calculator (FY 2026-27)
- Pakistan salary after tax calculator (FY 2026-27)
- Australia salary after tax calculator (2026-27)
- Job offer comparison: two salaries after tax
- Is working an extra day worth it?
- Pay rise vs childcare and household costs
- Second job tax calculator
- Rent affordability calculator
Islamic finance
Home & energy
Technology
Study
Health & fitness
Conversions
About Calculator786
What is Calculator786?
Calculator786 is a free collection of 88 online calculators for everyday maths, money and business, home and energy, technology, study and health. Each one shows its formula and assumptions next to the answer.
How is Calculator786 different from other calculator sites?
Calculator pages show their formula and assumptions. Numeric tools can rank which inputs change the result most, compare scenarios and save result cards; availability depends on the calculation. Calculations run in your browser and no account is needed.
Is Calculator786 free and private?
Yes, it is free with no sign-up. Inputs are processed in your browser and are not sent to a server. A share link contains the numbers you choose to share, so check it before sending.
Which currencies and regions does it support?
Amounts can be labelled in 33 currencies and numbers follow your browser locale. On the calculators, the currency selector changes labels only. To convert between currencies, type a question such as “100 usd to pkr” into the box at the top: it uses daily reference rates for about 160 currencies. Tax rates, prices and other local figures are entered by you, so the tools work anywhere.
Can it convert units, percentages and dates?
Yes. Type a question into the box at the top, such as “5 ft 7 in to cm”, “18% of 2400”, “90 days from today” or “(3+4)^2/7”. It understands 156 units in 14 families, lakh and crore, percentages, dates and maths, and shows how it read your question and the working. The full version is on the Convert page.
Can I trust the results?
Calculations use documented formulas and automated tests. Results are estimates based on the assumptions shown, not financial, tax, legal or medical advice.