Unit Converters
Unit converters turn a value in one measurement unit into its equivalent in another, helping students, engineers, cooks, travelers, and developers swap between metric, imperial, and digital units in seconds.
Convert acres to hectares instantly. Enter acres to get hectares using the 0.404686 factor, with the reverse hectares to acres direction shown.
Convert acres to square feet instantly and back. Uses the exact 43,560 sq ft per acre figure, with worked examples, a land-size chart and common acre to sq ft conversions.
Convert amps to watts with this calculator. Enter current in amps and the voltage to find power in watts, using the formula watts equals amps times volts.
Free area converter: enter one value and instantly see square meters, square feet, acres, hectares, square inches, yards, km and more using exact factors.
Convert bar to PSI instantly. Enter pressure in bar to get pounds per square inch, with the exact conversion factor and the reverse PSI to bar direction shown.
Convert BTU per hour to watts instantly. Enter BTU/hr to get watts by dividing by 3.412142, with the reverse watts to BTU/hr direction shown.
Convert calories to joules instantly. Enter calories or food Calories (kcal) to get joules using the 4.184 factor, with the reverse direction shown.
Convert between Celsius, Fahrenheit and Kelvin instantly. Enter any temperature to see all three scales, plus the C to F formula, worked examples and a reference chart from −40°C to 100°C.
Convert Celsius to Kelvin instantly. Enter a temperature in °C to get Kelvin by adding 273.15, with the reverse Kelvin to Celsius direction shown.
Convert centimeters to inches instantly and back. Uses the exact 0.393701 inches per cm factor, with worked examples, a size chart and common cm to in conversions.
Convert cups to milliliters instantly and back. Supports US cups (236.6 mL) and metric cups (250 mL), with worked examples, a baking chart and common cup to mL conversions.
Convert cups to fluid ounces instantly. Enter US cups to get fluid ounces, with the factor of 8 and the reverse fluid ounces to cups direction shown.
Convert any amount between currencies using the exchange rate you enter, then subtract a fee or markup to see exactly how much money you will actually receive.
Free data storage converter: enter one value and instantly see bits, bytes, KB, MB, GB, TB and PB at once using decimal SI factors where 1 KB = 1000 bytes.
Convert days to weeks instantly. Enter a number of days to get weeks by dividing by 7, plus a weeks-and-days breakdown and the reverse direction.
Convert feet to meters instantly and back. Uses the exact 0.3048 m per foot factor, with worked examples, a height chart and common ft to m conversions for height and distance.
Convert fluid ounces to milliliters instantly. Enter US fluid ounces to get mL, with the factor of 29.5735 and the reverse mL to fl oz direction shown.
Free fuel economy converter for mpg to l/100km, plus UK MPG and km/L. Enter one figure and see every unit instantly using exact, verified conversion factors.
Convert gallons to liters instantly. Works for US and Imperial gallons in both directions, with the exact conversion factors, worked examples and a quick reference chart.
Convert grams to kilograms instantly. Enter grams to get kilograms by dividing by 1000, with the reverse kilograms to grams direction shown.
Convert grams to ounces instantly and back. Uses the exact 28.3495 g per ounce factor, with worked examples, a cooking-friendly chart and common weight conversions.
Convert hectares to acres instantly. Enter hectares to get acres using the 2.47105 factor, with the reverse acres to hectares direction shown.
Calculate the full cost of a hotel stay including nightly rate, taxes, resort fees and daily extras. See your total and all-in per-night cost instantly.
Convert horsepower to kilowatts instantly and back. Supports mechanical HP and metric HP (PS), with worked examples, a car-engine chart and the exact conversion factors.
Convert inches to centimeters instantly and back. Uses the exact 2.54 cm per inch factor, with worked examples, a screen-size chart and common in to cm conversions.
Convert inches to feet instantly. Enter inches to get feet by dividing by 12, plus a feet-and-inches breakdown and the reverse feet to inches direction.
Estimate your international roaming charges before you travel. Add data, calls, texts and daily passes to see your total trip cost instantly with steps.
Convert joules to calories instantly. Enter joules to get small calories or food Calories (kcal) by dividing by 4.184, with the reverse direction shown.
Convert Kelvin to Celsius instantly. Enter a temperature in K to get °C by subtracting 273.15, with the reverse Celsius to Kelvin direction shown.
Convert kilograms to pounds instantly and back. Uses the exact 2.20462 lb per kg factor, with worked examples, a body-weight chart and common kg to lb conversions.
Convert kilometers to miles instantly and back. Uses the exact 0.621371 miles per km factor, with worked examples, a running and driving chart and common km to mi conversions.
Convert kilowatts (kW) to horsepower (hp) instantly. Enter any kW value to get mechanical horsepower, with the conversion factor and reverse direction shown.
Convert knots to mph instantly. Enter a speed in knots to get miles per hour using the 1.15078 factor, with the reverse mph to knots direction shown.
Convert between millimetres, centimetres, metres, kilometres, inches, feet, yards and miles instantly — enter one value and see every unit at once using exact metre-based factors.
Convert light years to kilometers instantly. Enter light-years to get km using the 9.46 trillion km factor, with the reverse km to light-years direction.
Convert liters to gallons instantly. Supports US and Imperial gallons in both directions, with the exact conversion factors, worked examples and a reference chart.
Convert meters to feet instantly and back. Uses the exact 3.28084 feet per meter factor, with worked examples, a height chart and common m to ft conversions for height and distance.
Convert meters to yards instantly. Enter meters to get yards by dividing by 0.9144, with the exact factor and the reverse yards to meters direction shown.
Convert mg to ml using concentration or density. Enter milligrams and a concentration in mg per mL to find the volume in milliliters, with the formula shown.
Convert micrograms to milligrams instantly. Enter mcg to get mg by dividing by 1000, with the reverse milligrams to micrograms direction shown.
Convert miles to kilometers instantly and back. Uses the exact 1.609344 km per mile factor, with worked examples, a running and driving chart and common mi to km conversions.
Convert millimeters to inches instantly. Enter mm to get inches by dividing by 25.4, with the exact factor and the reverse inches to mm direction shown.
Convert mph to knots instantly. Enter a speed in miles per hour to get knots by dividing by 1.15078, with the reverse knots to mph direction shown.
Convert ounces to grams instantly and back again. Uses the exact 28.3495 g per ounce factor, with worked examples, a kitchen-friendly chart and common cooking conversions.
Convert pints to cups instantly. Enter US pints to get cups, with the factor of 2 and the reverse cups to pints direction shown for quick recipe math.
Convert pounds to kilograms instantly and back. Uses the exact 0.45359237 kg per pound factor, with worked examples, a body-weight chart and common lb to kg conversions.
Free pressure converter for psi, bar, kPa, atm, mmHg and torr. Convert any pressure unit instantly using exact pascal base factors, accurate to 7 figures.
Convert PSI to bar instantly. Enter pounds per square inch to get pressure in bar, with the exact conversion factor and the reverse bar to PSI direction shown.
Convert quarts to gallons instantly. Enter US quarts to get gallons, with the factor of 4 and the reverse gallons to quarts direction shown.
Free Roman numeral converter: turn any number (1-3999) into Roman numerals and translate Roman numerals back to numbers instantly, using the standard I, V, X, L, C, D, M symbols.
Convert seconds to minutes instantly. Enter seconds to get minutes by dividing by 60, plus a minutes-and-seconds breakdown and the reverse direction.
Convert between kilometres per hour, miles per hour, metres per second, feet per second and knots instantly using exact base-unit factors.
Convert square meters to square feet instantly and back. Uses the exact 10.7639 sq ft per sq m factor, with worked examples, a floor-area chart and common m2 to sq ft conversions.
Convert stone to pounds instantly. Enter a weight in stone to get pounds, with the exact factor of 14 and the reverse pounds to stone direction shown.
Convert tablespoons to cups instantly and back. Uses the standard 16 tablespoons per cup ratio, with worked examples, a baking chart and common tbsp to cup conversions.
Convert teaspoons to milliliters instantly and back. Supports US teaspoons (4.93 mL) and metric teaspoons (5 mL), with worked examples and a dosing and baking chart.
Convert tons to kilograms instantly. Supports metric tonnes, US short tons and UK long tons, with worked examples, a reference chart and the exact conversion factors.
Free volume converter for litres, millilitres, cubic metres and US cooking units. Enter one value and see ml, cups, fluid ounces, pints, quarts and gallons at once.
Convert watts to amps with this calculator. Enter power in watts and the voltage to find the current in amps, using the formula amps = watts divided by volts.
Convert between milligrams, grams, kilograms, metric tonnes, ounces, pounds and stones instantly — enter one value and see every unit at once, using exact NIST conversion factors.
Convert yards to feet instantly and back. Uses the exact 3 feet per yard ratio, with worked examples, a fabric and field chart and common yard to foot conversions.
What are unit converters tools?
Unit converters translate a measurement from one unit into an equivalent value in another unit of the same physical quantity, such as temperature, length, mass, speed, area, volume, digital data, pressure, or fuel economy. They remove the need to memorize conversion factors or do error-prone manual math, giving students, engineers, cooks, travelers, and developers quick, accurate results.
Unit Converters tools on Toolzent
Toolzent’s converters cover the units people look up most often. Pick the one that matches your measurement type.
| Tool | What it does |
|---|---|
| Celsius to Fahrenheit Converter | Converts temperatures between degrees Celsius and degrees Fahrenheit in either direction. |
| Length Converter | Converts between length units such as millimeters, centimeters, meters, kilometers, inches, feet, yards, and miles. |
| Weight Converter | Converts between mass and weight units such as grams, kilograms, ounces, pounds, and stones. |
| Speed Converter | Converts between speed units such as kilometers per hour, miles per hour, meters per second, and knots. |
| Area Converter | Converts between area units such as square meters, square feet, acres, and hectares. |
| Volume Converter | Converts between volume units such as liters, milliliters, gallons, quarts, cups, and cubic meters. |
| Data Storage Converter | Converts between digital storage units such as bytes, kilobytes, megabytes, gigabytes, and terabytes. |
| Pressure Converter | Converts between pressure units such as pascals, kilopascals, bar, atmospheres, psi, and millimeters of mercury. |
| Roman Numeral Converter | Converts between Arabic numbers and Roman numerals in either direction, for example 2026 to MMXXVI. |
| Fuel Economy Converter | Converts between fuel economy units such as miles per gallon, kilometers per liter, and liters per 100 km. |
Common unit conversion factors
The factors below are the fixed, standard ratios most converters use, handy for quick mental checks.
| Conversion | Relationship |
|---|---|
| Inches to centimeters | 1 in = 2.54 cm (exact) |
| Miles to kilometers | 1 mi = 1.609344 km |
| Pounds to kilograms | 1 lb = 0.45359237 kg (exact) |
| Gallons (US) to liters | 1 gal = 3.785411784 L |
| Acres to square meters | 1 acre = 4046.8564 sq m |
| Atmospheres to pascals | 1 atm = 101325 Pa |
| Pounds per square inch to kilopascals | 1 psi = 6.89476 kPa |
| Gigabytes to megabytes (SI) | 1 GB = 1000 MB |
| Celsius to Fahrenheit | F = (C x 9/5) + 32 |
Length, weight, volume, area, speed, pressure, and data conversions are simple multiplications by a constant factor, while temperature needs a formula because the scales start from different zero points. Fuel economy is an inverse relationship, so a higher miles-per-gallon figure corresponds to a lower liters-per-100-km figure.
How do I choose the right tool?
Match the tool to the quantity you are measuring:
- Temperatures from a thermostat, recipe, or forecast map to the Celsius to Fahrenheit Converter.
- Distances, heights, and dimensions use the Length Converter for metric and imperial lengths.
- Kilograms, pounds, ounces, and stones go through the Weight Converter.
- Vehicle, wind, or running speeds use the Speed Converter.
- Land, rooms, and floor plans use the Area Converter for square units, acres, and hectares.
- Recipes and container sizes use the Volume Converter for liters, gallons, and cups.
- Files, drives, and bandwidth use the Data Storage Converter for bytes and larger digital units.
- Tire, weather, and engineering pressures use the Pressure Converter for psi, bar, kPa, and atmospheres.
- Clock faces, copyright years, and chapter headings use the Roman Numeral Converter.
- A car’s efficiency across regions uses the Fuel Economy Converter for mpg, km/L, and L/100km.
Why use Toolzent’s unit converters tools?
Toolzent’s unit converters are 100% free with no sign-up and nothing to install. They run privately in your browser, so the numbers you enter stay on your device and are never uploaded. Results appear instantly as you type, the layout is mobile-friendly, and each tool page shows the underlying formula or factor with a worked example. Because the factors match internationally defined constants, the figures match what you would calculate by hand, without the rounding slips.
For related calculations, explore our Math & Algebra, Date, Time & Age, and Statistics category hubs.
Frequently asked questions
Are these unit converters free to use?+
Yes. Every unit converter on Toolzent is 100% free, with no account, sign-up, or download required.
Do I need to install anything or create an account?+
No. The converters run entirely in your web browser, so there is nothing to install and no login to remember.
How accurate are the conversions?+
Conversions use standard, internationally defined factors (for example 1 inch equals exactly 2.54 cm), so results are accurate for everyday and most professional use.
What is the difference between metric and imperial units?+
Metric units (meters, grams, Celsius) are based on powers of ten, while imperial and US customary units (feet, pounds, Fahrenheit) come from older systems; converters translate between the two.
Why does converting Celsius to Fahrenheit need a formula instead of a simple factor?+
Temperature scales have different zero points, so you multiply by 9/5 and add 32 rather than multiplying by a single ratio like you do for length or weight.
Do data storage converters use 1000 or 1024 as the step between units?+
It depends on the standard: decimal SI units step by 1000 (kB, MB, GB) while binary units step by 1024 (KiB, MiB, GiB), which is why advertised and reported sizes can differ.