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Unit Converter & Calculators You Can Trust
Convert metric, US customary and UK imperial units in one step, check today's USD, CAD, GBP and EUR rates, and work out mortgages, sales tax, VAT and BMI. Every answer uses exact published factors and shows the formula, a worked example and a chart.
- 500+conversion pages with formulas and charts
- NIST & BIPMexact factors, cited on every page
- 21 calculatorsfor money, tax, health and school
- Expert reviewedby Dr. Muhammad Amjad Khadim, PhD Mathematics
Browse converters by category
Twelve converters covering everyday, engineering and finance units.
- CurrencyLive currency converter — US Dollar, Euro, British Pound, Pakistani Rupee, and more, from daily exchange rates.
- LengthLength converter for metric and imperial distances — millimeters up to miles.
- Weight and MassMass and weight converter — milligrams up to metric tons, plus pounds, ounces, and stone.
- TemperatureConvert Celsius, Fahrenheit, and Kelvin — including the classic weather-forecast conversion.
- VolumeVolume converter for cooking and liquid measurements — milliliters up to gallons.
- AreaArea converter for land, floor space, and real estate — square feet up to acres and hectares.
- SpeedSpeed converter for driving, weather, and aviation — mph, km/h, and knots.
- TimeTime converter — milliseconds up to years.
- PressurePressure converter for weather, tires, and engineering — psi, bar, and atmospheres.
- AngleAngle converter for geometry and trigonometry — degrees, radians, and gradians.
- PowerPower converter for engines and electronics — watts, kilowatts, and horsepower.
- Data StorageDigital storage converter for files and drives — bits up to terabytes.
Popular conversions
The conversions people in the US, UK and Canada look up most.
- Centimeters to Inches
- Inches to Centimeters
- Feet to Meters
- Meters to Feet
- Kilometers to Miles
- Miles to Kilometers
- Centimeters to Feet
- Millimeters to Inches
- Kilograms to Pounds
- Pounds to Kilograms
- Stone to Kilograms
- Kilograms to Stone
- Grams to Ounces
- Ounces to Grams
- Degrees Celsius to Degrees Fahrenheit
- Degrees Fahrenheit to Degrees Celsius
- Liters to US Gallons
- US Gallons to Liters
- Liters to UK Gallons
- UK Gallons to Liters
- UK Pints to Milliliters
- Milliliters to US Cups
- Milliliters to US Fluid Ounces
- Square Feet to Square Meters
- Square Meters to Square Feet
- Acres to Hectares
- Hectares to Acres
- Kilometers per Hour to Miles per Hour
- Miles per Hour to Kilometers per Hour
- US Dollars to Euros
- Euros to US Dollars
- US Dollars to British Pounds
- British Pounds to US Dollars
- US Dollars to Canadian Dollars
- Canadian Dollars to US Dollars
- Bars to Pounds per Square Inch
- Pounds per Square Inch to Bars
- Horsepower to Kilowatts
- Kilowatts to Horsepower
- Gigabytes to Megabytes
- Terabytes to Gigabytes
- Hours to Months (average)
- Kilowatts to Watts
- US Tablespoons to US Fluid Ounces
- Square Meters to Square Kilometers
Calculators
All calculators →Money and finance
VAT and sales tax
Everyday maths
Health and fitness
School and science
Sales tax in the US and Canada
2026 rates with a calculator for every state and province.
Sales tax by US state
State and average local rates for all 50 states and DC, ranked, with worked examples.
Canada sales tax by province
GST, HST, PST and QST for every province and territory, split line by line.
UK VAT and Canadian GST
Add or remove 20% UK VAT, EU VAT or Canadian GST/HST from any price in one click.
VAT calculator GST/HST calculatorWhy people trust pakmath.com
Accuracy first: no rounded shortcuts, no guesswork.
Exact, cited factors
Fixed-unit conversions use the legal definitions, such as 1 inch = 25.4 mm and 1 lb = 0.45359237 kg, from NIST and the BIPM.
Formula and worked example
Every page shows how the answer is calculated, so you can check it or redo it by hand.
Reviewed by a mathematician
Content is checked by Dr. Muhammad Amjad Khadim, PhD Mathematics. Read our editorial policy and about us.
Fast and free
No sign-up and no paywall. Results appear as you type, on phone or desktop.
Guides and articles
Visit the blog →The complete guide to unit conversion
Exact factors, temperature formulas, US vs imperial traps and currency pitfalls.
How to use online calculators correctly
Order of operations, VAT and sales tax, loan formulas, rounding and floating-point error.
Stone, pounds and kilograms explained
How UK body weight in stone converts to pounds and kilograms, with a quick chart.
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Regional units: South Asia
Converting marla, kanal, tola, seer or maund? See our guide to South Asian units and converters.
Frequently asked questions
Is pakmath.com free to use?
Yes. Every converter on pakmath.com is free, needs no signup and works on phones and computers.
How accurate are the conversions?
Fixed-unit conversions (length, weight, volume, area and so on) use exact, published factors such as 1 inch = 25.4 mm and 1 lb = 0.45359237 kg, taken from NIST and the BIPM. Results are shown to up to 10 decimal places, and every page is reviewed by Dr. Muhammad Amjad Khadim, PhD Mathematics.
Are there calculators as well as converters?
Yes. There are free calculators for mortgages, loans, compound interest, VAT, Canadian GST/HST, US sales tax, percentages, BMI, calories, dates, GPA, fractions and more, each with its formula and a worked example.
Where do the currency exchange rates come from?
Currency rates come from ExchangeRate-API's open data, updated daily and cached for up to 12 hours. They are mid-market reference rates, so banks and exchange companies will quote different buying and selling rates.
Which units can I convert?
Currency, length, weight and mass, temperature, volume, area, speed, time, pressure, angle, power and data storage, in metric, US customary and UK imperial units. Regional South Asian units such as marla, tola and maund are covered too.
How do I convert from one unit to another?
Open the converter for your category, or use the search box above: type a number, choose the "from" and "to" units, and the result appears instantly. Each conversion also has its own page with a table, formula and FAQ.