Calculator Suite

Unit Converters

Convert between different units of measurement with precision and ease. Our comprehensive collection covers 10 categories with over 50 units.

10
Categories
50+
Units
SI
Reference factors
Length & Distance
Easy
Convert between meters, feet, inches, miles, kilometers and more

Available Units

mm, cm, m, km, in, ft, yd, mi, nmi, ly

Popular Conversions

ft to mmi to kmin to cm
Weight & Mass
Easy
Convert between kilograms, pounds, ounces, grams and other mass units

Available Units

mg, g, kg, t, oz, lb, st, ton

Popular Conversions

lb to kgoz to gkg to lb
Temperature
Medium
Convert between Celsius, Fahrenheit, Kelvin and Rankine scales

Available Units

°C, °F, K, °R

Popular Conversions

°F to °C°C to °FK to °C
Volume & Capacity
Easy
Convert between liters, gallons, cups, milliliters and other volume units

Available Units

ml, L, gal, qt, pt, cup, fl oz, tbsp, tsp

Popular Conversions

gal to Lcup to mlfl oz to ml
Area
Medium
Convert between square meters, feet, acres, hectares and other area units

Available Units

mm², cm², m², km², in², ft², yd², acre, ha

Popular Conversions

ft² to m²acre to hain² to cm²
Speed & Velocity
Easy
Convert between mph, km/h, m/s, knots and other speed units

Available Units

m/s, km/h, mph, kn, ft/s

Popular Conversions

mph to km/hkm/h to m/skn to mph
Energy
Medium
Convert between joules, calories, BTU, kilowatt-hours and other energy units

Available Units

J, kJ, cal, kcal, Wh, kWh, BTU

Popular Conversions

kcal to kJkWh to JBTU to kJ
Time
Easy
Convert between seconds, minutes, hours, days, weeks, months and years

Available Units

ms, s, min, h, day, week, month, year

Popular Conversions

h to minday to hyear to day
Pressure
Hard
Convert between pascals, bar, psi, atmospheres and other pressure units

Available Units

Pa, kPa, bar, atm, psi, mmHg, torr

Popular Conversions

psi to baratm to kPammHg to kPa
Digital Storage
Medium
Convert between bytes, kilobytes, megabytes, gigabytes and binary units

Available Units

bit, B, KB, MB, GB, TB, KiB, MiB, GiB, TiB

Popular Conversions

GB to TBMB to GBMiB to MB
Conversion Accuracy

Our converters use documented conversion factors and display rounded results for readability. Keep input precision in mind when a decision depends on small differences.

• SI base units as primary standards

• NIST-certified conversion factors

• Temperature offset calculations

• Binary vs decimal digital units

Measurement Systems

Convert seamlessly between metric (SI), imperial, and specialized measurement systems used worldwide.

• Metric: Most countries worldwide

• Imperial: United States, UK (partial)

• Scientific: Research and engineering

• Specialized: Maritime, aviation, cooking

Quick Tips

Get the most from our unit converters with these helpful tips and common conversion shortcuts.

• Use scientific notation for very large/small values

• Temperature needs offset calculations (not just scaling)

• Digital storage: 1000 vs 1024 base differences

• Cooking: US vs UK measurements differ

How this calculator works
Method, formula, examples, assumptions, and review notes for this calculator.

How this calculator works

  • Most unit categories convert through a shared base unit such as meter, kilogram, second, joule, or pascal.
  • Temperature conversions use offset formulas rather than simple multiplication because zero points differ.
  • Digital storage distinguishes decimal units such as KB from binary units such as KiB.

Formula

Unit conversion by factor

valuetarget=valuesource×factorsourcefactortargetvalue_{target} = value_{source} \times \frac{factor_{source}}{factor_{target}}

Plain text formula: Target value = source value multiplied by the source unit factor divided by the target unit factor.

value_{source} = entered quantity in the source unit
factor_{source} = source unit factor relative to a base unit
factor_{target} = target unit factor relative to the same base unit

Worked examples

Miles to kilometers

Inputs

  • Distance: 5 miles
  • Factor: 1 mile = 1.609344 kilometers

Calculation

  • 5 x 1.609344 = 8.04672 kilometers.

Rounding to 8.05 km is appropriate for everyday use, while engineering work may need more precision.

Curated video guide
Selected YouTube lessons that add context after the calculator, formulas, examples, assumptions, and limitations.

Math Antics - Intro to the Metric System

Source: mathantics on YouTube

Why this video: Selected because it explains metric place-value structure that supports many converter categories.

What it adds: It supplements the hub's base-unit method by showing why metric conversions often move by powers of ten.

Use with this calculator: Use any converter first, then use the video to understand why metric-to-metric changes are usually systematic.

Limits: The video focuses on metric units and does not cover every imperial, binary storage, pressure, or temperature edge case.

How to interpret your result

  • Choose rounding based on the precision of the original measurement.
  • Do not imply more certainty than the input value supports.

Assumptions

  • Conversion factors are applied within the same measurement dimension.
  • The input unit and output unit are selected correctly.
  • Displayed rounding is for readability; internal calculations can keep more precision.

Limitations

  • Some practical units have context-specific definitions, such as US versus imperial volume.
  • Rounding can create small differences when chaining conversions.
  • Temperature and digital storage conversions require special handling.

Common mistakes

  • Converting between incompatible dimensions.
  • Treating Celsius-to-Fahrenheit as a simple factor conversion.
  • Confusing decimal storage units with binary storage units.

Sources

NIST Guide to the SI: conversion factorsNIST unit conversion references

Disclaimer

Last updated and reviewed by

Updated 2026-06-06Calculator Suite editorial review