A meter is the base unit of length in the International System of Units. It is the central reference for metric length: centimeters, millimeters, kilometers, and many scientific and engineering units are defined through their relationship to the meter.
Quick facts
- Unit name
- meter
- British spelling
- metre
- Plural
- meters
- Symbol
- m
- Quantity
- length
- System
- International System of Units
- SI role
- base unit for length
- Common relations
- 1 m = 100 cm = 1,000 mm
Visual scale
One meter is a human-scale length: larger than a classroom ruler, smaller than a typical doorway height, and ideal for rooms, furniture, sports distances, and construction dimensions.
Definition and SI role
The meter is the SI base unit for length. In practical unit conversion, it functions as the anchor for metric length units: centimeters are hundredths of a meter, millimeters are thousandths of a meter, and kilometers are thousands of meters.
Because the meter is the reference unit, many derived units include it directly: meters per second for speed, square meters for area, cubic meters for volume, newtons per square meter for pressure, and watts per meter-kelvin for thermal conductivity.
Symbol and writing rules
The standard symbol for meter is m. Unit symbols are not pluralized, so write 1 m and 12 m, not 12 ms. A space is normally placed between the number and the symbol in technical writing.
Meter vs metre
Meter is the common US spelling. Metre is the common British and international English spelling. The unit symbol is the same in both spellings: m. For conversion and technical use, spelling does not change the value of the unit.
| Spelling | Where it appears often | Symbol |
|---|---|---|
| meter | US English | m |
| metre | British and international English | m |
How big is one meter?
One meter is suitable for dimensions that are too large for centimeters but too small for kilometers. It is close to the length of a long step, the height of a countertop plus extra distance, or the width of many everyday spaces.
Everyday scale
One meter equals 100 cm, a convenient size for furniture, rooms, curtains, cables, and household measurements.
Sports and movement
Track distances, swimming pools, jumps, throws, and field dimensions often use meters.
Technical scale
Engineering and science often convert values to meters before using formulas that expect SI units.
Metric hierarchy around the meter
The meter sits at the center of decimal length conversion. Prefixes make smaller and larger units without changing the underlying quantity.
| Unit | Symbol | Relationship to meter | Typical use |
|---|---|---|---|
| millimeter | mm | 0.001 m | thickness, hardware, small parts |
| centimeter | cm | 0.01 m | body measurements, object dimensions |
| decimeter | dm | 0.1 m | education and metric scale demonstrations |
| meter | m | 1 m | rooms, height, sports, construction, science |
| kilometer | km | 1,000 m | roads, geography, maps, travel distance |
Meter vs foot
The meter and foot are both common human-scale length units. The meter belongs to the metric and SI system; the foot belongs to imperial and US customary measurement. Their relationship is based on the exact inch-centimeter definition.
Visual comparison
Use meters when working with SI formulas, metric specifications, international dimensions, science, and engineering. Use feet when the source measurement is already written in US customary form, such as real estate dimensions or construction references in the United States.
Common uses
Meters are used whenever a length is large enough that centimeters become noisy but not so large that kilometers are natural.
- Human height in scientific, medical, and international contexts.
- Room dimensions, ceiling height, furniture placement, and construction measurements.
- Sports distances, track events, swimming pools, jumps, and field measurements.
- Engineering, physics, surveying, architecture, and technical specifications.
- Maps, plans, scale drawings, cables, fabric, and installation measurements.
How to measure in meters
To measure in meters, choose a tool that matches the scale: a meter stick for short straight lengths, a tape measure for rooms and furniture, or a laser distance meter for larger interior distances. Record the value with enough decimal places to match the tool.
- Align the zero mark with the starting point, or verify the tool accounts for its own body length.
- Keep the tape or measuring tool straight along the measured dimension.
- Read meters first, then centimeters or millimeters as decimal parts of a meter.
- Write the unit with the number, such as 2.35 m, not only 2.35.
Precision and rounding
Metric length conversion around the meter is exact when it uses powers of ten. Rounding issues usually appear when converting meters to feet, inches, or miles, or when a measuring tool cannot support the number of decimal places written.
Everyday rounding
For rooms and furniture, two decimal places in meters often gives centimeter-level readability, such as 1.82 m.
Technical rounding
For engineering work, use the precision required by the specification and keep extra digits until the final result is reported.
Conversion formulas
Metric formulas involving meters are usually powers of ten. Customary conversions use exact inch and foot relationships.
Meter conversion table
| Meters | Centimeters | Millimeters | Feet | Inches |
|---|---|---|---|---|
| 0.01 m | 1 cm | 10 mm | 0.032808399 ft | 0.3937007874 in |
| 0.1 m | 10 cm | 100 mm | 0.32808399 ft | 3.937007874 in |
| 1 m | 100 cm | 1,000 mm | 3.280839895 ft | 39.37007874 in |
| 2 m | 200 cm | 2,000 mm | 6.56167979 ft | 78.74015748 in |
| 10 m | 1,000 cm | 10,000 mm | 32.80839895 ft | 393.7007874 in |
Common mistakes
- Pluralizing the symbol: write 12 m, not 12 ms, when using the meter symbol.
- Confusing m and mm: 1 m equals 1,000 mm, so this mistake creates a factor-of-1,000 error.
- Dropping decimal zeros: 2.05 m and 2.5 m are very different lengths.
- Using feet formulas with meter inputs: check whether a formula expects SI units before substituting values.
- Mixing length, area, and volume: m measures length, m2 measures area, and m3 measures volume.
Related Xunits pages
Meter converters
Length references
FAQ
Is the meter an SI base unit?
Yes. The meter is the SI base unit for length.
How many centimeters are in one meter?
One meter equals exactly 100 centimeters.
How many millimeters are in one meter?
One meter equals exactly 1,000 millimeters.
How many feet are in one meter?
One meter equals approximately 3.280839895 feet.
How many inches are in one meter?
One meter equals approximately 39.37007874 inches.
Is meter spelled metre?
Meter is the common US spelling. Metre is the common British and international English spelling. Both use the same symbol, m.
Should I use meters or centimeters?
Use meters for larger human-scale dimensions such as rooms, height, and sports distances. Use centimeters for smaller object dimensions and body measurements when whole numbers are easier to read.
Should I use meters or millimeters?
Use meters for overall dimensions and SI calculations. Use millimeters for small parts, thickness, technical tolerances, and engineering drawings.
What is the difference between m, m2, and m3?
m measures length, m2 measures area, and m3 measures volume. They are related but not interchangeable.
Why do scientific formulas often use meters?
Many scientific formulas are written in SI units, and the meter is the SI base unit for length. Using meters helps keep derived units coherent.
Is one meter exactly 100 centimeters?
Yes. The relationship is exact because centi- means one hundredth.
Is one meter exactly 3 feet?
No. One meter is about 3.280839895 feet, so using 3 feet is only a rough estimate.
Reference notes
This guide treats the meter as the SI base unit for length and uses exact decimal relationships for metric prefixes. Customary conversions use the exact international inch relationship and the exact 12-inch foot relationship.
- The meter is the SI base unit for length.
- One meter equals exactly 100 centimeters.
- One meter equals exactly 1,000 millimeters.
- One foot equals exactly 0.3048 meters.