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Metric to Standard Converter

Convert between metric length units (mm, cm, m, km) and standard US units (in, ft, yd, mi), including a feet plus inches format.

Formula shown0 inputs definedUpdated Dec 2025By CalcuTotal TeamFree, no sign-up

Quick Summary

Use this when you need:

Convert a metric dimension into inches for hardware and shop work
Translate metric building dimensions into feet
Compare kilometers and miles for travel distances

You’ll get:Length

How this is calculated

Formula:

in = mm / 25.4; ft = m / 0.3048

In plain language:

The inch is defined as 25.4 mm, and the foot is defined as 0.3048 m. This converter routes everything through meters so you can swap between any pair without stacking rounding errors.

The formula is always visible so you can verify the math and explain your numbers to anyone who asks.

What these terms mean

Length

Length used in the calculation.

When to use this calculator

Convert a metric dimension into inches for hardware and shop work
Translate metric building dimensions into feet
Compare kilometers and miles for travel distances

Last updated: December 26, 2025

Metric to standard converter explained

"Standard" usually means US units like inches, feet, and miles. Metric specs use millimeters, centimeters, meters, and kilometers. This converter keeps both sets side by side so you can convert without redoing the same math.

How the conversion works

Two exact definitions anchor most conversions:

1\\,\\text{in} = 25.4\\,\\text{mm}

1\\,\\text{ft} = 0.3048\\,\\text{m}

Once you can convert to inches or meters, the rest follow with fixed ratios.

Units and conversions

Unit	Symbol	Relation
Millimeter	mm	$10^{-3}\\,\\text{m}$
Centimeter	cm	$10^{-2}\\,\\text{m}$
Meter	m	base unit
Kilometer	km	$1000\\,\\text{m}$
Inch	in	$1\\,\\text{in} = 25.4\\,\\text{mm}$
Foot	ft	$12\\,\\text{in} = 1\\,\\text{ft}$
Mile	mi	$5280\\,\\text{ft} = 1\\,\\text{mi}$

Worked examples

Converting 250 mm to inches
$\\text{in} = \\frac{250}{25.4} = 9.84252\\,\\text{in}$
Result: 9.84252 in.
Converting 1 km to miles
$1\\,\\text{km} = 1000\\,\\text{m}$ $\\text{mi} = \\frac{1000}{1609.344} = 0.621371\\,\\text{mi}$
Result: 0.621371 mi.

Tips and pitfalls

Convert once, then round. Repeated rounding across steps accumulates error.
For heights and interior dimensions, feet plus inches is easier to read than decimal feet.
If you are matching parts, keep the tolerance unit consistent; 0.1 mm and 0.004 in are close but not identical.

References and further reading

Frequently Asked Questions

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Calculator info

Version:: v1.0.0
Last reviewed:: Dec 26, 2025
Sensitivity:: low
References:: 1

Last updated: December 26, 2025

Metric to standard converter explained

How the conversion works

Two exact definitions anchor most conversions:

1\\,\\text{in} = 25.4\\,\\text{mm}

1\\,\\text{ft} = 0.3048\\,\\text{m}

Once you can convert to inches or meters, the rest follow with fixed ratios.

Units and conversions

Unit	Symbol	Relation
Millimeter	mm	$10^{-3}\\,\\text{m}$
Centimeter	cm	$10^{-2}\\,\\text{m}$
Meter	m	base unit
Kilometer	km	$1000\\,\\text{m}$
Inch	in	$1\\,\\text{in} = 25.4\\,\\text{mm}$
Foot	ft	$12\\,\\text{in} = 1\\,\\text{ft}$
Mile	mi	$5280\\,\\text{ft} = 1\\,\\text{mi}$

Worked examples

Converting 250 mm to inches
$\\text{in} = \\frac{250}{25.4} = 9.84252\\,\\text{in}$
Result: 9.84252 in.
Converting 1 km to miles
$1\\,\\text{km} = 1000\\,\\text{m}$ $\\text{mi} = \\frac{1000}{1609.344} = 0.621371\\,\\text{mi}$
Result: 0.621371 mi.

Tips and pitfalls

Convert once, then round. Repeated rounding across steps accumulates error.
For heights and interior dimensions, feet plus inches is easier to read than decimal feet.
If you are matching parts, keep the tolerance unit consistent; 0.1 mm and 0.004 in are close but not identical.

Quick Summary

Calculator Tool

How this is calculated

What these terms mean

Length

When to use this calculator

Metric to standard converter explained

How the conversion works

Units and conversions

Worked examples

Tips and pitfalls

References and further reading

Frequently Asked Questions

Related Calculators

Metric to Imperial Converter

Metric to Inches Calculator

Centimeter Calculator

Foot to Centimeter Converter

Feet to Meters Converter

Meter Converter

Was this calculator helpful?

Found an error?

Calculator info

Metric to standard converter explained

How the conversion works

Units and conversions

Worked examples

Tips and pitfalls

References and further reading

Frequently Asked Questions

Related Calculators

Metric to Imperial Converter

Metric to Inches Calculator

Centimeter Calculator

Foot to Centimeter Converter

Feet to Meters Converter

Meter Converter

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