Tape Measure Fraction Calculator

Work with tape-measure fractions directly. Add, subtract, find a difference or half, and convert between fractional and decimal inches.

Your measurements

Midpoint means half the entered measurement, measured from zero.

Measurement A

Use 0 for less than one inch.

Choose 0 for whole inches only.

Measurement B

Use 0 for less than one inch.

Choose 0 for whole inches only.

How it works

Enter whole inches and a fraction separately, choosing the fraction shown on your tape. We keep the fraction exact, carry extra whole inches and simplify the answer. Subtraction keeps a negative result; difference gives the nonnegative distance between the measurements.

Midpoint gives half of one measurement. An exact half can fall between the finest tape marks, such as 1/128 inch. Decimal-to-fraction mode rounds to your chosen tape precision and shows the resulting decimal inches and rounding adjustment.

Useful information

For a whole measurement, choose fraction 0. For a fraction alone, enter whole inches 0. Each measurement row combines whole inches with the fraction you select.

Measurements are entered as positive lengths. Subtraction can give a negative result when Measurement B is larger than Measurement A. Difference gives the positive distance between them, or zero when they match. A negative feet-and-inches result applies its sign to the whole measurement.

Decimal inputs accept ordinary decimal notation with up to six decimal places. Exact halfway rounding goes away from zero. If a small negative decimal rounds to zero, the result is shown as 0 rather than negative zero.

This is fraction math, not a screen ruler. No on-screen element represents a physically accurate length. Confirm measurements on your actual tape before cutting.

Calculation aid only. Check units, measurement direction and tape precision before marking or cutting.