Length to Millimeters Converter (Supports Fractions)
Convert Inches (decimal & fractional), Feet, and Meters to Millimeters. Essential for carpentry, machining, and blueprint conversion.
About
Precision manufacturing and construction often face a "language barrier" between Imperial units (standard in the US) and Metric units (standard elsewhere). A common friction point arises when blueprints specify fractional dimensions like "1 3/8 inch" or "4 1/2 inch," which standard calculators fail to parse directly.
This tool bridges that gap by accepting complex fractional strings alongside standard decimals. It converts inputs directly to millimeters (mm), the standard unit for machining tolerances and 3D printing parameters. It eliminates the manual step of converting fractions to decimals before applying the metric conversion factor.
Formulas
The core conversion relies on the exact definition of the inch:
For fractions (e.g., "a bc"):
Reference Data
| Fractional Inch | Decimal Inch | Millimeters (mm) | Usage Context |
|---|---|---|---|
| 1/32" | 0.03125 | 0.7938 | Fine shims |
| 1/16" | 0.0625 | 1.5875 | Standard Sheet Metal |
| 1/8" | 0.125 | 3.1750 | Welding electrodes |
| 1/4" | 0.250 | 6.3500 | Hardware fasteners |
| 1/2" | 0.500 | 12.7000 | Piping, Plywood |
| 3/4" | 0.750 | 19.0500 | Lumber thickness |
| 1" | 1.000 | 25.4000 | Base unit |
| 1 1/2" | 1.500 | 38.1000 | Framing lumber (2x4 width) |