Length Unit Converter
mm · cm · m · km · inches · feet · yards · miles
Convert any length unit instantly centimeters to inches, kilometers to miles, feet to meters, millimeters to centimeters, and every combination in between. Type a value, see all units at once, copy in one click.
9+
Units Supported
Metric + Imperial
Systems
All at Once
Output
None
Account Needed
Instant Conversion, One-Click Copy
Everything a length converter should do fast, accurate, metric and imperial in one view
Instant All-Unit Output
Type once and see all units mm, cm, m, km, in, ft, yd, mi update simultaneously. No re-entering values.
One-Click Copy
Copy any individual result to clipboard instantly. Designed for fast paste-into-workflow use on desktop and mobile.
Metric & Imperial Together
Convert seamlessly between SI metric (mm, cm, m, km) and imperial/US customary (in, ft, yd, mi) units in one view.
High-Precision Results
Full floating-point precision no premature rounding. Useful for engineering, construction, and scientific work.
Mobile Responsive
Fully works on smartphones and tablets no app needed. Open in any mobile browser and use immediately.
No Signup Required
Completely free, no account. All units and features available instantly.
All Length Units Explained
Every supported unit with its conversion factor to meters and a quick example
÷ 1,000× 1,00010 mm = 1 cm÷ 100× 100100 cm = 1 m× 1× 11 m = 100 cm× 1,000÷ 1,0001 km = 1,000 m× 0.0254÷ 0.02541 in = 2.54 cm× 0.3048÷ 0.30481 ft = 12 in× 0.9144÷ 0.91441 yd = 3 ft× 1,609.344÷ 1,609.3441 mi = 1.609 km× 1,852÷ 1,8521 nmi = 1,852 mMetric (SI) Units
Used globally in science, engineering, and most countries. Based on powers of 10 easy to convert. Millimetre (mm) → Centimetre (cm) → Metre (m) → Kilometre (km).
1 km = 1,000 m = 100,000 cm = 1,000,000 mmImperial / US Customary Units
Used in the US, UK (partially), and in some industries. Inch (in) → Foot (ft) → Yard (yd) → Mile (mi). Based on historical definitions, now fixed relative to metric.
1 mi = 1,760 yd = 5,280 ft = 63,360 inExact Formulas for Every Common Conversion
Use these to calculate manually or verify the tool's output
cm ÷ 2.5430 cm = 11.81 inin × 2.5412 in = 30.48 cmft × 0.30485 ft = 1.524 mm ÷ 0.30481.8 m = 5.91 ftkm ÷ 1.6093410 km = 6.214 mimi × 1.609345 mi = 8.047 kmmm ÷ 1025 mm = 2.5 cmcm ÷ 100150 cm = 1.5 mm ÷ 1,0003,500 m = 3.5 kmyd × 0.9144100 yd = 91.44 mft × 126 ft = 72 incm ÷ 30.48 (ft), remainder ÷ 2.54 (in)175 cm = 5 ft 8.9 inConversion Examples from Everyday Situations
Height, running, engineering, construction see how conversions work in context
Height Conversion 175 cm to Feet & Inches
A person is 175 cm tall. What is that in feet and inches?
Running Distance 10 km to Miles
A race is 10 km. How far is that in miles?
Engineering / School 250 mm to cm and m
A metal rod is 250 mm. What is that in cm and m?
Construction Room Width 15 ft to Meters
A room is 15 feet wide. What is that in meters for a floor plan?
For Students, Engineers, and Everyday Use
One tool that fits every workflow from homework to construction blueprints
Students & Educators
- Convert cm to m or mm to cm for maths and science homework
- Solve mixed-unit problems: feet to meters, inches to centimeters
- Check conversion answers instantly during exam preparation
- Understand metric vs imperial systems with side-by-side outputs
Engineers & Architects
- Switch between mm/cm/m for technical drawings and CAD dimensions
- Convert imperial plan measurements (ft/in) to metric specs (m/cm)
- Calculate material lengths across unit systems without error
- Get full-precision output not rounded approximations
Fitness, Sports & Travel
- Convert race distances km to miles for running, cycling events
- Check your height in feet/inches vs centimetres for forms and profiles
- Convert road distances miles to km when travelling internationally
- Understand athletic field dimensions across metric and imperial formats
DIY, Crafts & Everyday Use
- Convert furniture dimensions from cm to inches for online shopping
- Calculate fabric lengths: yards to meters for sewing projects
- Convert screen sizes (inches) to cm for international product comparisons
- Quick room measurements: feet to meters for flooring calculations
Frequently Asked Questions
The most searched length conversion questions — with short, example-driven answers
Core Length Conversions
Enter your centimeter (cm) value, select cm as the source unit, and the inch (in) result appears instantly. Formula: cm ÷ 2.54 = inches. Example: 30 cm ÷ 2.54 = 11.81 inches. One inch is exactly 2.54 centimetres by international definition. Copy the result with one click.
Exactly 1 inch = 2.54 centimetres (cm). This is a fixed, exact value — not an approximation. In reverse: 1 cm = 0.3937 inches. Common reference: 30 cm ≈ 11.81 in; 1 foot (12 inches) = 30.48 cm.
Feet to meters: ft × 0.3048 = m. Example: 5 ft = 1.524 m. Meters to feet: m ÷ 0.3048 = ft. Example: 1.8 m = 5.906 ft. One foot (ft) = 30.48 cm = 0.3048 meter (m) exactly. Select your source unit and the converter outputs both directions simultaneously.
Kilometres to miles: km ÷ 1.60934 = mi. Example: 10 km = 6.214 miles (mi). Miles to kilometres: mi × 1.60934 = km. Example: 5 mi = 8.047 km. The exact conversion is 1 mile = 1,609.344 metres (m) = 1.609344 km. Quick mental check: multiply km by 0.6 for a rough mile estimate.
UntangleTools Length Converter supports all standard units: millimeter (mm), centimeter (cm), meter (m), kilometer (km), inch (in), foot (ft), yard (yd), mile (mi), and nautical mile. Enter any value, select the source unit, and all outputs update simultaneously. One-click copy for each result. Free, no signup, works on mobile.
Four steps: (1) Type or paste a number into the input. (2) Select the source unit from the dropdown — mm, cm, m, km, in, ft, yd, or mi. (3) All conversions update instantly — no button press needed. (4) Click the Copy icon next to any unit to copy that result to your clipboard. Works the same on desktop and mobile.
Yes. The tool converts freely between SI metric units (millimetre / mm, centimetre / cm, metre / m, kilometre / km) and imperial / US customary units (inch / in, foot / ft, yard / yd, mile / mi). Select any metric unit as input and see all imperial outputs, or vice versa. No separate mode switch needed.
100 cm = 1 metre (m) exactly. 150 cm = 1.5 m. Formula: cm ÷ 100 = m. More examples: 200 cm = 2 m; 75 cm = 0.75 m; 50 cm = 0.5 m. In imperial: 100 cm = 39.37 inches = 3.28 feet; 150 cm = 59.06 inches = 4.92 feet (approximately 4 ft 11 in).
Yes. The converter is fully responsive — tap-friendly inputs, readable output rows, and one-tap Copy buttons optimised for touchscreens. Open untangletools.com/unit/category/length in Chrome, Safari, or any mobile browser on iPhone, Android, or tablet. No app download needed. You can also paste values from other apps directly into the input field on mobile.
More Converters on UntangleTools
All free, all instant — the complete unit conversion toolkit
Weight Converter
kg to lb, g to oz, and all weight units instantly.
Try tool →Temperature Converter
Celsius, Fahrenheit, Kelvin instant bidirectional.
Try tool →Data Storage Converter
GB to MB, TB to GB, bits to bytes and more.
Try tool →Speed Converter
km/h to mph, m/s to knots for travel and engineering.
Try tool →Area Converter
m² to ft², acres to hectares, and more.
Try tool →Volume Converter
Liters to gallons, ml to fl oz, cubic conversions.
Try tool →
