Inch Fraction Calculator

Enter a decimal inch value or a fraction to convert between the two, rounded to a standard precision.

How to Use the Inch Fraction Calculator

In Decimal → Fraction mode, enter a decimal inch value and pick a rounding precision (1/8, 1/16, 1/32, or 1/64) — the calculator rounds to the closest mark at that precision and reduces the result. In Fraction → Decimal mode, enter a whole number, numerator, and denominator to get the decimal equivalent instead.

numerator = round(decimal remainder × denominator)
reduced fraction = numerator ÷ gcd(numerator, denominator), denominator ÷ gcd(numerator, denominator)

A tape measure doesn't print 3.28 inches anywhere on it — it prints tick marks at sixteenths or thirty-seconds, so a shop drawing's decimal dimensions need translating before they mean anything at the bench. The reduction step matters too: rounding 3.28" to the nearest 1/16 lands on 9/16 past the 3" mark, not 18/32, even though both are mathematically identical — nobody reads a tape measure in thirty-seconds when sixteenths will do.