Unit Converter
Choose a value and source unit on the left, then check the converted result, unit, formula, and examples on the right.
Input
InputResult
ResultFormula
Examples
For this categoryready to use.
- Visible firstKeep the input and result positions clear.
- Results firstPut the main number up front and keep the process secondary.
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Read the unit with the number: a US everyday conversion guide
This converter moves a source value into a result unit across length, weight, temperature, area, volume, time, speed, and data. The number alone is incomplete: 12 in, 12 ft, and 12 cm are three different lengths. Pick the quantity, enter the source value, then read the result with both unit labels.
For US use, inches, feet, pounds, miles, Fahrenheit, US gallons, and fluid ounces often come first in everyday material. SI equivalents are useful alongside them: 6 ft is 1.8288 m, and 1 lb is about 453.592 g. Currency is not a measurement category here; this tool has no rates or currency conversion.
Start with what is being measured
Choose a category before choosing units. Enter a source value in the left pane and select the result unit in the right pane. Changing the category selects its US-oriented pair—such as mi → km, lb → kg, or °F → °C—while keeping the current number, then updates the result, notes, formula, and examples.
- Package dimensions: in, ft, cm, or m
- Recipes and shipping: oz, lb, g, or kg
- Driving and weather: mph, km/h, °F, or °C
Everyday US units still have SI relationships
A tape measure may say 36 in, a room may be 10 ft wide, and a road trip may be 50 mi. The same tool gives 36 in = 0.9144 m, 10 ft = 3.048 m, and 50 mi = 80.4672 km. These straight conversions use the selected source factor divided by the selected result factor.
For a quote or a packing list, retain the original unit even after converting. A value that was supplied in pounds is not automatically a kilogram value.
US and UK liquid labels are not interchangeable
The volume list includes both US gallons and UK gallons. A US gallon is about 3.78541 L; a UK gallon is about 4.54609 L. It also labels US fluid ounces, quarts, pints, and cups separately from a 250 mL metric cup and a 200 mL Japanese cup.
- 16 US fl oz is about 473.176 mL
- 1 US cup is about 236.588 mL
- Check the label’s country before treating “gal” or “cup” as one fixed amount
Fahrenheit and Celsius need an offset
Temperature is not a factor-only conversion because Fahrenheit, Celsius, and kelvin use different zero points. For example, 68 °F equals 20 °C, while 20 °C equals 293.15 K. The current-pair formula shown by the tool includes the needed addition or subtraction.
Use the symbol as well as the number on a thermostat, recipe, weather alert, or lab note. A temperature difference is not always handled the same way as an absolute temperature conversion.
The formula and examples do different jobs
The formula panel explains the active category and its current unit pair. The examples panel is a small category sample made from that category’s first three units; it does not reproduce your entered value as a full table.
- Use the result pane for your typed value
- Use the formula to check the selected direction
- Expect the examples to change when you change category
Swap, Copy, and Reset are separate actions
Swap exchanges the chosen source and result units but leaves your entered number in place. Copy creates one line with the source value and label, an equals sign, and the result value and label. Reset uses the US-oriented starting pair for the open category: 32 °F → °C for temperature, 60 mph → km/h for speed, and 100 ft² → m² for area.
Reset does not remove favorite pairs. Remove a favorite from its saved list when it is no longer useful.
Favorites stay in this browser
Star a pair such as mi → km or lb → kg to save its category and two unit choices. Choosing it later resets the input to 1 and calculates that pair. The saved item is not a saved measurement or a shared account record.
- It may remain in the same browser profile
- It does not automatically move to another device or browser
- Clearing browser/site data can remove it
Read rounding and data sizes with care
The US English page groups input while you type, so 1234.5 appears as 1,234.5, and formats the result the same way. Ordinary results use up to six decimal places; very small or very large values switch to exponential notation.
Data units are decimal here: 1 KB = 1,000 bytes and 1 MB = 1,000 KB. If a specification uses 1,024-based capacity, look for IEC names such as KiB and MiB or read the document’s own definition.
Use the governing source for regulated work
This is a quick conversion aid, not a calibrated instrument or legal record. For trade, surveying, healthcare, safety, calibration, or contractual work, use the applicable standard, source document, and calibrated equipment.
- BIPM publishes SI reference material
- NIST provides US SI and customary-unit context
- Currency conversion is outside this tool
Unit converter questions
Does this converter handle currency?
No. It covers length, weight, temperature, area, volume, time, speed, and data quantities. It has no exchange rates or currency conversion.
Why is temperature converted differently?
Celsius, Fahrenheit, and kelvin do not share the same zero point. Their conversions therefore use an offset as well as a multiplier.
Does Swap reverse my entered number?
No. Swap exchanges the selected source and result units, while the entered number stays in the source field and is recalculated in the new direction.
Where are favorite unit pairs saved?
They are saved only in this browser's local storage as a category and a pair of units. They are not synced to another device or browser and may disappear when browser data is cleared.
Can I use the displayed digits for a regulated measurement?
The display is formatted for readability. For contracts, legal metrology, calibration, medical work, or safety decisions, check the governing standard, source record, or calibrated instrument.
Check official definitions and the requirements that govern the work before relying on a converted value.