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All calculators & converters
Free calculators and unit converters for scientific maths, currency, digital assets and economic data. Saving an expression is optional.
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Unit converterskg→lbs, mi→km, °C→°F, L→gal, ft²→m² and more.Browse Online calculatorsLoan payments, bill splitting, quadratic equations.Browse Reference figuresCurrency values, digital assets, economic indicators.BrowseCommon starting points
Every link below opens the relevant tool with its inputs already filled in. Change any value, then press that tool's confirmation button to reveal the result. For a focused page per task — with its own explanation and a confirm-to-reveal widget — see the worked guides and their linked converter, calculator and reference pages.
Unit conversions
- Meters to feetLength conversion with every other length unit listed alongside.m ÷ 0.3048
- Miles to kilometersDistance conversion using the exact international mile definition.mi × 1.609344
- Inches to centimetersSmall-measurement length conversion.in × 2.54
- Square feet to square metersArea conversion using the squared length factor.ft² × 0.09290304
- Pounds to kilogramsMass conversion using the exact avoirdupois pound definition.lb × 0.45359237
- Kilograms to poundsReverse mass conversion.kg ÷ 0.45359237
- Celsius to FahrenheitTemperature conversion including its offset, with absolute-zero checks.°C × 9⁄5 + 32
- Fahrenheit to CelsiusReverse temperature conversion.(°F − 32) × 5⁄9
- Liters to US gallonsVolume conversion, with Imperial gallons labelled separately.L ÷ 3.785411784
- km/h to mphSpeed conversion from the defined kilometre and mile.km/h × 0.621371…
- MB to MiBDecimal-to-binary data-size conversion.MB × 10⁶ ÷ 2²⁰
- GB to GiBLarger decimal-to-binary data-size conversion.GB × 10⁹ ÷ 2³⁰
Formula presets
- Compound interestFixed-rate growth with a chosen compounding frequency.P × (1 + r/n)^(n×t)
- Loan paymentIllustrative equal monthly payments at a fixed annual rate.P(r⁄12) ⁄ (1 − (1 + r⁄12)^(−12n))
- Quadratic positive rootOne branch of the quadratic formula; change the sign for the other root.(−b + √(b² − 4ac)) ⁄ 2a
- Two linear equationsSolve a small matrix system and check both residuals.A·x = b
- Matrix determinantDeterminant of a two-by-two matrix.det([1, 2; 3, 4])
- Circle areaArea from a radius expressed in the same length unit.π × r²
- Heat changeSensible heat at constant specific heat capacity.m × c × ΔT
- Fuel estimateDistance, consumption and price per litre combined.d × u ⁄ 100 × p
- Tip splitSplit a bill and a proportional tip evenly.bill × (1 + tip) ⁄ people
- PaceAverage minutes per unit of distance.minutes ⁄ distance
- Mortgage total interestInterest paid over a full fixed-rate term, excluding fees.payment × 12n − P
- Savings goal — monthly depositEqual monthly deposits to reach a target at a fixed rate.goal × (r⁄12) ⁄ ((1 + r⁄12)^(12t) − 1)
- Future value of depositsWhat regular monthly deposits grow to over t years.d × ((1 + r⁄12)^(12t) − 1) ⁄ (r⁄12)
- Inflation-adjusted valueA future amount expressed in today's purchasing power.amount ⁄ (1 + i)^t
- Real rate of returnNominal return with inflation removed (Fisher relation).(1 + nominal) ⁄ (1 + inflation) − 1
- Effective annual rateNominal rate compounded n times a year, as an annual equivalent.(1 + r⁄n)ⁿ − 1
- Currency spread costWhat a conversion costs against the mid-market rate.amount × (mid − offered) + fee
- Percentage changeChange between two prices, index values or balances.(current − previous) ⁄ previous × 100
- Break-even unitsUnits to sell before revenue covers all costs.fixed ⁄ (price − variable)
- Position size by riskUnits to buy so a stop-loss caps the loss at a chosen fraction of capital.capital × risk ⁄ (entry − stop)
Reference figures
- US inflation rateConsumer-price inflation for the United States, with history.
- Japan GDP per personGross domestic product per capita for Japan.
- Germany unemploymentUnemployment measure for Germany.
- India populationTotal population for India.
- US dollar to euroIndicative reference conversion with its rate date and recent trend.
- Pound to US dollarReference conversion for GBP to USD.
- Digital-asset pricesSelected prices and daily movement, filterable by name or symbol.
- Euro area GDP growthAnnual GDP growth for Germany, the largest euro-area economy.
- Brazil lending rateLending interest rate for Brazil, with history.
- Japan government debtCentral government debt as a share of GDP for Japan.
- US current accountCurrent account balance as a share of GDP for the United States.
- Euro to Polish złotyReference conversion for EUR to PLN.
- Yen to Thai bahtReference conversion for JPY to THB.
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Reference informationExternal figures may be delayed, revised or temporarily unavailable.
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