Length Converter
A length converter changes a measurement from one unit to another by multiplying by a fixed factor. Every unit is defined against the meter: 1 inch = 2.54 cm exactly, 1 foot = 0.3048 m, 1 mile = 1,609.344 m. Example: 100 cm ÷ 2.54 = 39.3701 inches.
Method and limits
Enter a complete number; dot decimals are accepted. A decimal comma also works in comma-decimal locales. Blank is unavailable, not zero. No grouping or unit suffixes. Maximum 100 significant digits, exponent −100…100, 256 characters. Display rounds half away from zero to the selected precision. Calculations run in your browser; surrounding site requests still exist.
Result
not a number
Paste a spreadsheet column, one value per line. Semicolons, tabs and spaces separate values too, and so does a comma — unless it groups thousands inside one number, as in 1,234, which is read as 1234.
Paste or type at least one number to convert.
| # | Input () | Result () |
|---|---|---|
All Conversions
Common Conversions
Reference Table
| From | m | ft | in | km |
|---|---|---|---|---|
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How do you convert length units?
Every conversion is one multiplication and one division. Take the value, multiply by the source unit's size in meters, then divide by the target unit's size in meters. Going from yards to inches: 40 yd × 0.9144 = 36.576 m, then ÷ 0.0254 = 1,440 in. The meter is the pivot, so ten units need ten factors instead of ninety pairs — and no intermediate result is ever rounded before the last step.
What are the exact length conversion factors?
Factors marked exact are fixed by definition, not measured. The rest are those definitions inverted and rounded to six decimals.
| Conversion | Multiply by | Example |
|---|---|---|
| Inches → Centimeters | 2.54(exact) | 10 in = 25.4 cm |
| Centimeters → Inches | 0.393701 | 10 cm = 3.937 in |
| Feet → Meters | 0.3048(exact) | 6 ft = 1.8288 m |
| Meters → Feet | 3.280840 | 2 m = 6.5617 ft |
| Yards → Meters | 0.9144(exact) | 100 yd = 91.44 m |
| Miles → Kilometers | 1.609344(exact) | 5 mi = 8.04672 km |
| Kilometers → Miles | 0.621371 | 10 km = 6.2137 mi |
| Millimeters → Inches | 0.039370 | 25 mm = 0.9843 in |
| Nautical Miles → Kilometers | 1.852(exact) | 12 nmi = 22.224 km |
| Micrometers → Millimeters | 0.001(exact) | 500 µm = 0.5 mm |
How do you convert height in feet and inches to centimeters?
Multiply total inches by 2.54. Forms usually want a whole number of centimeters, so the last column is what you write down.
| Height | Total inches | Centimeters |
|---|---|---|
| 5 ft 0 in | 60 | 152.4 |
| 5 ft 2 in | 62 | 157.5 |
| 5 ft 4 in | 64 | 162.6 |
| 5 ft 6 in | 66 | 167.6 |
| 5 ft 8 in | 68 | 172.7 |
| 5 ft 10 in | 70 | 177.8 |
| 6 ft 0 in | 72 | 182.9 |
| 6 ft 2 in | 74 | 188.0 |
Can you convert a length into square meters or a diameter?
No, and this is the most common misuse of a length converter. Square meters are an area and need two dimensions: 4 m × 3 m = 12 m². A diameter needs a circle: divide a circumference by π (100 mm around gives a 31.83 mm diameter). Convert the units first, then do the geometry — mixing the two steps is where the mistakes come from.
Which units does this length converter support?
Ten units in both directions: micrometer (µm), millimeter (mm), centimeter (cm), meter (m) and kilometer (km) on the metric side; inch (in), foot (ft), yard (yd), mile (mi) and nautical mile (nmi) on the other. The micrometer covers coating thickness and machining tolerances, the nautical mile covers marine and aviation charts. Any of the ten converts to any other, and the all-conversions grid shows all ten at once.
Sources
Definitions and conversion factors on this page follow the official US and international references:
- NIST Special Publication 811 — Guide for the Use of the International System of Units (conversion factors, Appendix B.8)
- NIST Office of Weights and Measures — Unit conversion
- BIPM — The International System of Units (SI Brochure), definition of the meter
- NIST — U.S. Survey Foot: obsolete since 1 January 2023, superseded by the international foot
About Length Converter
Convert metric, international imperial and nautical lengths, singly or in a batch. 1 in = 0.0254 m; 1 mi = 1609.344 m; 1 nmi = 1852 m.
1 in → 2.54 cm; 1 mi → 1609.344 m; 1.5 m → 150 cm.
Illustrative examples; no publication or accuracy certification.
Use Cases
How to convert a length step by step
Choose units, enter a number, then read or copy the current result.
Pro Tips
- Change the precision to control display rounding.
Frequently Asked Questions
Yes. This converter uses the international inch, exactly 0.0254 metres or 2.54 centimetres. Its mile is exactly 1609.344 metres; it does not use the former US survey foot.
No. Length is one-dimensional; area needs two dimensions. The international inch is exactly 2.54 cm. Survey feet and regional length units are not included.