One length converter for every unit you will meet: millimeters, centimeters, meters, kilometers, inches, feet, yards, miles and nautical miles. Pick the two units, type a value, and the answer appears instantly — all in your browser, with no sign-up and nothing uploaded.
It is the tool to reach for when a recipe, a pattern, a map or a specification mixes metric and imperial. A US road trip is measured in miles, a marathon in kilometers, a room in feet and a bolt in millimeters — and this page handles every pair without a second tab. If you only ever convert one pair, a dedicated page is quicker — try the Centimeter to Inch converter — and the BMI Calculator takes your height in feet and inches or centimeters.
How to use
- Choose the unit you are converting from and the unit you want.
- Type a value in either box — the other side updates instantly.
- Use the swap button to flip the direction without retyping.
- Check the table below for the exact size of every unit in meters.
Why use Toolsvine
Nine units in one page beats nine bookmarks. This converter stores every unit as its exact size in meters and converts through that single reference, so every pair agrees with every other pair — no contradictory factors, no server round-trip, no ads in the way, and it works offline once loaded. Whether you are checking a 5K race distance, a bookshelf in feet or a bolt in millimeters, the answer is one page away.
How does the length conversion work?
Every unit is stored as its exact length in meters. To convert, the tool divides by the source unit's meter value and multiplies by the target unit's — one formula for all 72 possible pairs, so a mile converted to feet and then to meters always lands on the same answer as converting directly.
Every unit, in meters
| Unit | Symbol | Meters |
|---|---|---|
| Millimeter | mm | 0.001 |
| Centimeter | cm | 0.01 |
| Meter | m | 1.0 |
| Kilometer | km | 1000.0 |
| Inch | in | 0.0254 |
| Foot | ft | 0.3048 |
| Yard | yd | 0.9144 |
| Mile | mi | 1609.344 |
| Nautical mile | nmi | 1852.0 |
The inch (0.0254 m) and the foot (0.3048 m) are exact by international definition, and the mile (1,609.344 m) follows from them. The nautical mile is different: 1,852 meters exactly, defined from the Earth's circumference and used at sea and in the air. A yard is three feet, or 0.9144 meters.
Worked example: a marathon in miles and kilometers
A marathon is 42.195 kilometers, which is 26.2188 miles. The converter divides 42.195 by 1.609344 (the size of a mile in kilometers) to get 26.2188, the familiar 26.2-mile figure printed on race bibs across the US. The same method works for any pair: divide by the source unit's meters, multiply by the target's.
Try it the other way: a 5K race is 5 kilometers, or 3.10686 miles (5 ÷ 1.609344). A football field is 100 yards, or 91.44 meters (100 × 0.9144), and a 6-foot bookshelf is 1.8288 meters (6 × 0.3048). Because every conversion passes through meters, the answers always agree with each other.
Which unit should I use?
Use the unit your audience expects: feet and inches for rooms, furniture and height in the US, miles for road distances, millimeters for small parts and bolts, and meters or kilometers for science, running and international specs. For American readers, imperial first is the safe default; metric suits technical documents.
A handy rule of thumb: a meter is about 3 feet 3 inches, a kilometer is about 0.62 miles, and an inch is 2.54 centimeters. For everyday estimates those rounded figures are close enough, but for cutting, ordering or measuring a room use the exact converter above — a half-inch error on a bookshelf is a ruined weekend. Planning a road trip? The Mile to Kilometer converter turns highway distances into kilometers for rental cars and maps abroad.
Frequently asked questions
How many centimeters are in an inch?
Exactly 2.54 cm. The inch was defined as 2.54 centimeters by international agreement in 1959, so centimeter-to-inch conversions are exact, not approximate. That is why the converter never drifts: it uses the definition itself, and any difference you see between converters is only how many decimal places they display.
How many feet are in a meter?
One meter is about 3.28084 feet, or about 3 feet 3½ inches. A 2-meter doorway is about 6 feet 7 inches tall, a 100-meter sprint is 328 feet, and a standard US ceiling of 8 feet is 2.44 meters. The exact figure is 1 ÷ 0.3048, because the foot is defined as exactly 0.3048 meters.
What is a nautical mile, and how is it different from a mile?
A nautical mile is 1,852 meters — about 1.15 land miles. It equals one minute of latitude, which is why sailors and pilots use it for charts and navigation, while land distances use the 1,609.344-meter mile. A knot, the speed used at sea and in the air, is one nautical mile per hour, or about 1.15 miles per hour.
Why convert through meters instead of using a factor for each pair?
Converting through one reference unit guarantees consistency: converting miles to feet, then feet to meters, gives the same answer as converting miles to meters directly. Pair-by-pair factors rounded differently can disagree, so two answers on the same page could contradict each other. One reference keeps every pair honest.
Is my data uploaded when I convert?
No. The conversion runs in JavaScript in your browser, so your numbers never leave your device. The tool is free, needs no account, and works offline once the page has loaded. You can convert as many values as you like without creating an account or seeing an ad.