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Metric to Inches Calculator

Convert metric length units (mm, cm, m) to inches and back, with feet as a quick reference.

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

Quick Summary

Use this when you need:

Convert product dimensions from mm into inches
Translate drill bit sizes and tolerances between metric and inch specs
Cross-check drawings that mix mm and inch dimensions

You’ll get:Length

How this is calculated

Formula:

in = mm / 25.4

In plain language:

Inches are defined exactly in terms of millimeters: 1 inch equals 25.4 mm. Metric values convert to meters internally, then convert to inches using that exact factor.

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 product dimensions from mm into inches
Translate drill bit sizes and tolerances between metric and inch specs
Cross-check drawings that mix mm and inch dimensions

Last updated: December 26, 2025

Metric to inches calculator explained

Inches show up in hardware sizes, tool settings, and older drawings. Metric specs often use millimeters or centimeters. This calculator converts mm, cm, and meters to inches, and it also converts inches back to metric.

How the conversion works

The inch is defined exactly:

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

That gives a direct shortcut when your input is millimeters:

\\text{in} = \\frac{\\text{mm}}{25.4}

For centimeters, convert to millimeters first:

\\text{mm} = 10 \\times \\text{cm}

Units and conversions

Unit	Symbol	Relation
Millimeter	mm	$10^{-3}\\,\\text{m}$
Centimeter	cm	$10^{-2}\\,\\text{m}$
Meter	m	base unit
Inch	in	$1\\,\\text{in} = 25.4\\,\\text{mm}$

Worked examples

Converting 50 mm to inches
$\\text{in} = \\frac{50}{25.4} = 1.968504\\,\\text{in}$
Result: 1.968504 in.
Converting 2.54 cm to inches
Convert to mm:
$2.54\\,\\text{cm} = 25.4\\,\\text{mm}$
Then:
$\\text{in} = \\frac{25.4}{25.4} = 1\\,\\text{in}$
Result: 1 in.

Tips and pitfalls

For machining tolerances, keep at least four decimal places in inches during intermediate steps.
Decide whether you need decimal inches or fractional inches; the math is the same, but the display differs.
If you are converting a height or room dimension, feet can be a more readable reference than inches alone.

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 inches calculator explained

How the conversion works

The inch is defined exactly:

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

That gives a direct shortcut when your input is millimeters:

\\text{in} = \\frac{\\text{mm}}{25.4}

For centimeters, convert to millimeters first:

\\text{mm} = 10 \\times \\text{cm}

Units and conversions

Unit	Symbol	Relation
Millimeter	mm	$10^{-3}\\,\\text{m}$
Centimeter	cm	$10^{-2}\\,\\text{m}$
Meter	m	base unit
Inch	in	$1\\,\\text{in} = 25.4\\,\\text{mm}$

Worked examples

Converting 50 mm to inches
$\\text{in} = \\frac{50}{25.4} = 1.968504\\,\\text{in}$
Result: 1.968504 in.
Converting 2.54 cm to inches
Convert to mm:
$2.54\\,\\text{cm} = 25.4\\,\\text{mm}$
Then:
$\\text{in} = \\frac{25.4}{25.4} = 1\\,\\text{in}$
Result: 1 in.

Tips and pitfalls

For machining tolerances, keep at least four decimal places in inches during intermediate steps.
Decide whether you need decimal inches or fractional inches; the math is the same, but the display differs.
If you are converting a height or room dimension, feet can be a more readable reference than inches alone.

Quick Summary

Calculator Tool

How this is calculated

What these terms mean

Length

When to use this calculator

Metric to inches calculator 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 Standard Converter

Centimeter Calculator

Meter Converter

Metric to SAE Calculator

Millimeter Calculator

Was this calculator helpful?

Found an error?

Calculator info

Metric to inches calculator 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 Standard Converter

Centimeter Calculator

Meter Converter

Metric to SAE Calculator

Millimeter Calculator

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Found an error?

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