How to Read a Tape Measure (with a Fraction Chart)
A tape measure is read in whole inches first, then in fractions. Find the last full inch before your mark, then count the small lines past it to get the fraction.
Start with the longest lines
The longest lines mark whole inches, and they carry the numbers. If your edge sits between the 5 and the 6, you have 5 inches plus a fraction.
Read the fractions by line length
Between two inches, the lines get shorter as the fractions get smaller:
- The longest line between inches is the half (1/2).
- The next shorter lines are the quarters (1/4 and 3/4).
- Shorter again are the eighths (1/8, 3/8, 5/8, 7/8).
- The shortest lines are the sixteenths (1/16, 3/16, and so on).
Count the shortest lines from the last whole inch. If your mark is on the 7th short line, you have 7/16 of an inch.
Fraction chart
| Fraction | Decimal inches |
|---|---|
| 1/16 | 0.0625 |
| 1/8 | 0.125 |
| 3/16 | 0.1875 |
| 1/4 | 0.25 |
| 5/16 | 0.3125 |
| 3/8 | 0.375 |
| 7/16 | 0.4375 |
| 1/2 | 0.5 |
| 9/16 | 0.5625 |
| 5/8 | 0.625 |
| 11/16 | 0.6875 |
| 3/4 | 0.75 |
| 13/16 | 0.8125 |
| 7/8 | 0.875 |
| 15/16 | 0.9375 |
Feet and inches
Many tapes also print feet. Twelve inches make a foot, so 3 feet 4 inches is 40 inches. When you add lengths, convert everything to inches first, add, then convert back.
Adding fractions without the headache
Adding 5 3/8” and 2 7/16” means finding a common denominator: 3/8 becomes 6/16, so the sum is 7 and 13/16 inches. It is easy to slip when you are standing at a workbench with a pencil in your teeth.
That is the job Tape Mark does. You enter feet, inches and fractions, and the app shows the answer and where it falls on a tape, so you can find the mark on your real tape measure.
Frequently asked questions
What is the smallest mark on a standard tape measure?
On most US tape measures it is 1/16 of an inch. Some also show 1/32.
How do I know if a line is 1/4 or 3/8?
Compare line lengths. Quarters are longer than eighths, and eighths are longer than sixteenths.
Does the hook at the end of the tape matter?
Yes. The hook slides slightly so that inside and outside measurements both come out right. Do not bend it to “fix” it.