Ruler Fraction Chart
Use this ruler fraction chart to match common inch marks with their decimal and millimeter values.
Ruler Fraction Converter
Use the main calculator to enter fractions, decimals, mixed inch values, or millimeters. The chart below gives quick reference values for this page.
Open CalculatorRuler Marks to Decimal Inches
Common ruler marks from 1/16 through 1 inch with decimal and metric equivalents.
| Ruler mark | Decimal inches | Millimeters | Smaller precision |
|---|---|---|---|
| 1/16 | 0.0625 | 1.588 | 1/16 |
| 1/8 | 0.1250 | 3.175 | 1/8 |
| 3/16 | 0.1875 | 4.763 | 3/16 |
| 1/4 | 0.2500 | 6.350 | 1/4 |
| 5/16 | 0.3125 | 7.938 | 5/16 |
| 3/8 | 0.3750 | 9.525 | 3/8 |
| 7/16 | 0.4375 | 11.113 | 7/16 |
| 1/2 | 0.5000 | 12.700 | 1/2 |
| 9/16 | 0.5625 | 14.288 | 9/16 |
| 5/8 | 0.6250 | 15.875 | 5/8 |
| 11/16 | 0.6875 | 17.463 | 11/16 |
| 3/4 | 0.7500 | 19.050 | 3/4 |
| 13/16 | 0.8125 | 20.638 | 13/16 |
| 7/8 | 0.8750 | 22.225 | 7/8 |
| 15/16 | 0.9375 | 23.813 | 15/16 |
| 1 | 1.0000 | 25.400 | 1 |
Note: Values are based on 1 inch = 25.4 millimeters.
Reading ruler marks
- The longest marks usually show inches and half inches.
- Shorter marks show quarters, eighths, and sixteenths.
- Use the chart when a mark needs a decimal value.
Choosing precision
- Tape measures often stop at 1/16.
- Machinist rulers may show 1/32 or 1/64.
- Use the smallest mark your tool can read reliably.
More chart tools
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