Millimeters to Inches Converter
Convert between millimeters and inches for precise measurements and engineering applications
Length Conversion Calculator
Metric unit (1/1000 of a meter)
Imperial unit (1/12 of a foot)
Conversion Result
Quick Reference Conversions
| Millimeters | Inches | Description |
|---|---|---|
| 1 mm | 0.0394" | 1 millimeter |
| 5 mm | 0.1969" | 5 millimeters |
| 10 mm | 0.3937" | 1 centimeter |
| 25.4 mm | 1.0000" | 1 inch (exact) |
| 50.8 mm | 2.0000" | 2 inches |
| 76.2 mm | 3.0000" | 3 inches |
| 101.6 mm | 4.0000" | 4 inches |
| 152.4 mm | 6.0000" | 6 inches |
| 254 mm | 10.0000" | 10 inches |
| 304.8 mm | 12.0000" | 1 foot |
Unit Systems
Millimeter (Metric)
1/1000 of a meter
Precise measurements
Inch (Imperial/US)
1/12 of a foot
Common in US/UK
Scale Reference
Measurement Tips
1 inch = 25.4 millimeters exactly
Use millimeters for precise engineering
Use inches for construction in US
Quick estimate: 25 mm ≈ 1 inch
Understanding Millimeters and Inches
What are Millimeters?
A millimeter (mm) is a unit of length in the metric system equal to one thousandth of a meter. It's the standard unit for precise measurements in engineering, manufacturing, and science worldwide.
Common Uses
- •Technical drawings and CAD designs
- •Manufacturing tolerances and precision parts
- •Medical instruments and measurements
- •Electronic component specifications
What are Inches?
An inch (in) is a unit of length in the imperial and US customary systems equal to 1/12 of a foot or exactly 25.4 millimeters. It's commonly used in the United States and United Kingdom.
Conversion Formula
Millimeters to Inches
in = mm ÷ 25.4
Divide millimeters by 25.4
Inches to Millimeters
mm = in × 25.4
Multiply inches by 25.4
Understanding the Relationship
Exact Conversion
1 inch = 25.4 millimeters exactly. This is the international standard definition based on the meter.
Practical Examples
A smartphone screen is typically 150-160mm (6-6.3 inches). A credit card is 85mm (3.35 inches) long.
Quick Estimation
For quick estimates: 25 mm ≈ 1 inch, or 1 mm ≈ 0.04 inches. Use 25.4 for precise calculations.
Practical Applications
Millimeter Applications
- • Mechanical engineering drawings
- • PCB and electronic component sizing
- • Medical device specifications
- • Jewelry and watch making
- • Scientific research measurements
- • Manufacturing quality control
Inch Applications
- • Construction and carpentry in US/UK
- • Plumbing and pipe sizing
- • Screen sizes and displays
- • Screw and bolt specifications
- • Fabric and textile measurements
- • Tool and hardware sizing