Single Conversion
Batch Conversion
| # | Original | Inches | Meters | Millimeters | Centimeters | Scientific | Engineering | Snap mm | Δ mm | Copy |
|---|
How it works
The converter performs exact rational multiplication where possible using the identity 1 in = 127/5000 m (i.e., 0.0254 m). Parsing accepts decimals, simple fractions, mixed numbers, hyphenated mixed (e.g., 1-3/8), feet+inches (e.g., 5' 7-3/16"), and engineering formats (mils/thou, microinches). Basic arithmetic (+, −, ×, ÷, parentheses) is supported. Select rounding by decimal places or significant figures, and optionally snap to a target metric step (e.g., 0.5 mm).
Accessibility: Fully labeled controls, keyboard friendly (Enter to convert, Ctrl/Cmd+C to copy fields), and ARIA live updates for results.
What Is the Relationship Between Inches and Meters?
The inch is a customary (imperial) unit of length and the meter is the SI base unit of length. Their relationship is defined exactly: 1 inch = 0.0254 meters. Equivalently, 1 inch = 2.54 centimeters and 1 inch = 25.4 millimeters. This exactness comes from the international agreement that fixed the inch to the meter via the identity 1 in = 127/5000 m.
- m = in × 0.0254 (exact) and in = m ÷ 0.0254
- cm = in × 2.54 (exact), mm = in × 25.4 (exact)
- 1 m = 39.3700787402 in (the reciprocal of 0.0254)
- Optional historical variant: the US survey inch is about 0.0254000508 m (≈2 ppm longer), relevant only for legacy survey data.
Worked examples
- 5' 7" = 67 in → 1.7018 m (1701.8 mm)
- 1-3/8" = 1.375 in → 0.034925 m (34.925 mm)
- 250 mil = 0.250 in → 0.00635 m (6.35 mm)
| Inches | Meters | Millimeters |
|---|---|---|
| 1 | 0.0254 | 25.4 |
| 2 | 0.0508 | 50.8 |
| 6 | 0.1524 | 152.4 |
| 12 | 0.3048 | 304.8 |
| 36 | 0.9144 | 914.4 |
| 100 | 2.54 | 2540 |
Tip: Because 2.54 is exact, you can safely chain conversions through centimeters or millimeters without accumulating rounding error if you keep enough precision.
Simple Formula to Convert Inches to Meters
m = inches × 127/5000 (rational), cm = inches × 2.54, mm = inches × 25.4How to use it (3 quick steps)
- Express the length in inches (decimal or a fraction like
3 1/2or1-3/8). - Multiply by 0.0254 to get meters.
- Round to your desired precision or significant figures (e.g., 3–4 decimals for general work).
Examples
- 8 in → 8 × 0.0254 = 0.2032 m
- 3 1/2 in (= 3.5 in) → 3.5 × 0.0254 = 0.0889 m
- 0.05 in → 0.05 × 0.0254 = 0.00127 m (1.27 mm)
Common Inch Fractions → Millimeters
| Inches | Millimeters |
|---|---|
| 1/32 | 0.79375 |
| 1/16 | 1.5875 |
| 1/8 | 3.175 |
| 1/4 | 6.35 |
| 1/2 | 12.7 |
Mental-Math Tips
- 1 inch ≈ 25 mm (handy, about 1.6% low).
- 4 inches ≈ 0.10 m; 40 inches ≈ 1.0 m.
- For quick checks: inches × 2.5 ≈ cm (approximate).
Note: This tool uses the exact factor 0.0254. A legacy option “US survey inch” (~0.0254000508 m) is available for historic data.
Step-by-Step Example of Inch to Meter Conversion
Example A — Feet + Inches with a Mixed Fraction
- Feet to inches:
5 ft × 12 = 60 in. - Mixed inches:
7-3/16" = 7 + 3/16 = 7.1875 in. - Total inches:
60 + 7.1875 = 67.1875 in. - Convert to meters (exact factor):
67.1875 × 0.0254 = 1.7065625 m. - Round to 4 decimals (half-up): 1.7066 m.
- Millimeters:
1.7065625 × 1000 = 1706.5625 mm. - Snap to 0.5 mm: 1706.5 mm (Δ
-0.0625 mm) → 1.7065 m. - Tolerance propagation:
±0.005 in × 0.0254 = ±0.000127 m(±0.127 mm).
Example B — Common Fraction Only
- Fraction to decimal:
1-3/8" = 1.375 in. - Meters (exact):
1.375 × 0.0254 = 0.034925 m. - To 3 sig figs: 0.0349 m (34.9 mm). Exact mm is
34.925 mm.
Tip: The factor 0.0254 is exact, so you can also compute via millimeters (in × 25.4) and then divide by 1000 to get meters with identical results.