Inches to Fraction Calculator
Convert decimal inches to fractions instantly with our free calculator. Enter any decimal measurement and get the nearest fractional inch with your choice of precision (1/64", 1/32", 1/16", 1/8", 1/4"). Perfect for woodworking, carpentry, construction, and reading tape measures. Quick reference: 0.5" = 1/2" | 0.375" = 3/8" | 0.625" = 5/8".
Quick Decimal to Fraction Formula
Converting decimals to inch fractions is simple: multiply the decimal by your precision denominator, round to nearest whole number, and place over the denominator.
Example: 0.375" with 1/16 precision = Round(0.375 × 16) / 16 = 6/16 = 3/8"
💡 Quick Reference Decimals
💡 Common Fractions
💡 Common MM Sizes
📋 Decimal to Fraction Conversion Chart
Quick reference chart showing decimal inches and their fractional equivalents:
Common Decimal to Fraction Conversions (0" to 1")
| Decimal | Fraction | MM | Decimal | Fraction | MM |
|---|---|---|---|---|---|
| 0.0625 | 1/16" | 1.588 | 0.5625 | 9/16" | 14.288 |
| 0.125 | 1/8" | 3.175 | 0.625 | 5/8" | 15.875 |
| 0.1875 | 3/16" | 4.763 | 0.6875 | 11/16" | 17.463 |
| 0.25 | 1/4" | 6.35 | 0.75 | 3/4" | 19.05 |
| 0.3125 | 5/16" | 7.938 | 0.8125 | 13/16" | 20.638 |
| 0.375 | 3/8" | 9.525 | 0.875 | 7/8" | 22.225 |
| 0.4375 | 7/16" | 11.113 | 0.9375 | 15/16" | 23.813 |
| 0.5 | 1/2" | 12.7 | 1.0 | 1" | 25.4 |
32nds and 64ths Reference (High Precision)
| Fraction | Decimal | MM | Fraction | Decimal | MM |
|---|---|---|---|---|---|
| 1/32" | 0.03125 | 0.794 | 1/64" | 0.01563 | 0.397 |
| 3/32" | 0.09375 | 2.381 | 3/64" | 0.04688 | 1.191 |
| 5/32" | 0.15625 | 3.969 | 5/64" | 0.07813 | 1.984 |
| 7/32" | 0.21875 | 5.556 | 7/64" | 0.10938 | 2.778 |
| 9/32" | 0.28125 | 7.144 | 9/64" | 0.14063 | 3.572 |
| 11/32" | 0.34375 | 8.731 | 11/64" | 0.17188 | 4.366 |
| 13/32" | 0.40625 | 10.319 | 13/64" | 0.20313 | 5.159 |
| 15/32" | 0.46875 | 11.906 | 15/64" | 0.23438 | 5.953 |
📏 Understanding Tape Measure Markings
Pro Tip: On a tape measure, longer marks = larger fractions. The tallest mark is the whole inch, followed by 1/2", 1/4", 1/8", and 1/16" (shortest).
Conversion Formulas & Key Facts
Master these essential formulas for converting between decimal and fractional inches:
• Numerator = Round(Decimal × Denominator)
• Example: 0.375 with 1/16 precision → Round(0.375 × 16) = 6 → 6/16 = 3/8"
Fraction to Decimal:
• Decimal = Numerator ÷ Denominator
• Example: 3/8" → 3 ÷ 8 = 0.375"
Inches to Millimeters:
• MM = Inches × 25.4
• Example: 0.375" × 25.4 = 9.525 mm
Key fact: 1 inch = 25.4 mm (exact) | Valid denominators: 2, 4, 8, 16, 32, 64 (powers of 2)
🔍 Frequently Asked Questions About Inch Fractions
What is 0.375 inches as a fraction?
0.375 inches equals 3/8". This is one of the most common conversions. Calculation: 0.375 × 8 = 3, so 3/8". Also equals 6/16" or 12/32".
What is 0.625 inches as a fraction?
0.625 inches equals 5/8". This is commonly used in woodworking and construction. Calculation: 0.625 × 8 = 5, so 5/8" (15.875 mm).
How do I convert decimal to fraction on a tape measure?
Multiply your decimal by the smallest division on your tape (usually 16). Round to nearest whole number. Example: 0.75 × 16 = 12, so 12/16" = 3/4".
What is 0.5 inches in fraction?
0.5 inches equals 1/2". This is exactly half an inch, equal to 8/16", 4/8", or 12.7 mm. One of the easiest conversions to remember.
What fraction is 0.125 inches?
0.125 inches equals 1/8". This equals 2/16" or 4/32" in higher precision. In millimeters, it's 3.175 mm.
How do I read fractions on a ruler?
Ruler marks decrease in size: tallest = whole inch, next = 1/2", then 1/4", 1/8", and shortest = 1/16". Count the marks from the previous whole number.
What is 3/8 inch in decimal?
3/8" equals 0.375 decimal inches. Divide numerator by denominator: 3 ÷ 8 = 0.375. In millimeters, this is 9.525 mm.
What is the difference between 1/16 and 1/32 precision?
1/16" precision rounds to nearest 0.0625", while 1/32" rounds to 0.03125". Use 1/32" or 1/64" for precision machining; 1/16" suffices for most woodworking.
How do I convert mm to fractional inches?
First divide mm by 25.4 to get decimal inches, then convert to fraction. Example: 10 mm ÷ 25.4 = 0.3937" ≈ 3/8" (with some rounding error).
What is 0.75 inches as a fraction?
0.75 inches equals 3/4". This is equivalent to 6/8", 12/16", or 24/32". In metric, it's exactly 19.05 mm.
Why do inch fractions use powers of 2?
Inch fractions use denominators like 2, 4, 8, 16, 32, 64 because they're easy to divide by 2. This makes halving measurements simple on rulers and tape measures.
What is 5/16 inch in decimal?
5/16" equals 0.3125 decimal inches. Calculation: 5 ÷ 16 = 0.3125. In millimeters, this equals 7.9375 mm (approximately 8 mm).
👥 Who Uses the Inches to Fraction Calculator?
Woodworkers & Carpenters
Convert digital caliper readings to tape measure fractions. Set up saw blades, router bits, and marking gauges with precision measurements.
Construction Workers
Translate blueprint dimensions to tape measure readings. Cut drywall, lumber, and materials to exact specifications.
Machinists & Engineers
Convert between decimal specs and fractional tooling. Use 1/32" or 1/64" precision for tight tolerances in manufacturing.
DIY Enthusiasts
Make accurate cuts for home improvement projects. Understand measurement conversions for furniture assembly and repairs.
Sewers & Crafters
Convert pattern measurements between decimal and fractional inches. Ensure accurate seam allowances and hem measurements.
Students & Teachers
Learn fraction-decimal relationships. Practice measurement conversions for math, shop class, and practical applications.
❓ Inches to Fraction Calculator FAQ
To convert a decimal to a fraction: 1) Choose your precision (e.g., 1/16), 2) Multiply the decimal by the denominator, 3) Round to the nearest whole number, 4) Place over the denominator. Example: 0.375 with 1/16 precision → 0.375 × 16 = 6 → 6/16 = 3/8".
For most woodworking projects, 1/16" precision is sufficient. For fine furniture and joinery, use 1/32". Precision machining may require 1/64". Standard tape measures typically mark down to 1/16".
Inch fractions use denominators that are powers of 2 (2, 4, 8, 16, 32, 64) because they're easy to divide by 2 repeatedly. This makes it simple to find half of any measurement, which is practical for construction and manufacturing.
The calculator shows the nearest valid fraction to your decimal. Some rounding occurs because only specific denominators are valid. The calculator displays the rounding error percentage so you know how close the fraction is to the original decimal.
Tape measure marks vary in height by fraction size: Tallest marks = whole inches, then 1/2", 1/4", 1/8", and shortest marks = 1/16". Count the marks between whole inches to find your fraction.
Yes! Use our MM → Fraction tab. First, divide mm by 25.4 to get decimal inches, then convert to the nearest fraction. Note: metric measurements rarely convert to exact fractions, so some rounding is normal.
Reduced fractions are simplified to their lowest terms (e.g., 6/16 → 3/8). Both represent the same measurement. Our calculator automatically reduces fractions for easier reading.
To add fractions: 1) Find a common denominator, 2) Add the numerators, 3) Reduce if needed. Example: 1/4" + 3/8" = 2/8" + 3/8" = 5/8". Or convert to decimals (0.25 + 0.375 = 0.625"), then back to fraction.
This calculator uses mathematically precise conversion formulas based on the exact relationship: 1 inch = 25.4 millimeters. All fraction conversions use standard dyadic fractions (powers of 2 denominators).
Last reviewed and updated: February 15, 2026
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