Inches to Millimeters Converter
Convert inches to millimeters for engineering, manufacturing, tools, dimensions, printing, and product specifications. Millimeters provide a smaller metric unit that is useful for precise dimensions.
Quick Answer
Millimeters = Inches Γ 25.4
One inch is exactly 25.4 millimeters. Multiply inches by 25.4 to convert to millimeters.
Why Inches and Millimeters Are Both Used
Product specifications may combine imperial and metric measurements, especially for tools, fasteners, machinery, and manufactured parts. Converting the unit helps compare dimensions without changing the physical size being measured.
Precision Matters
When converting a small mechanical dimension, avoid premature rounding. Keep the full result until the final reporting step so the converted measurement remains consistent with the original precision.
Examples
1 inch = 25.4 mm.
2 inches = 50.8 mm.
5 inches = 127 mm.
10 inches = 254 mm.
Quick Reference
- 1 in = 25.4 mm exactly.
- Multiply inches by 25.4.
- For reverse conversion, divide millimeters by 25.4.