Where do these numbers come from?
- NISTSP 811 exact unit definitions (1 in = 25.4 mm, 1 lb = 453.59237 g)current edition
- NISTHandbook 44, weights and measurescurrent edition
- King Arthur BakingIngredient Weight Chart (kitchen tools)retrieved Oct 23, 2026
Checked Oct 23, 2026. 1 inch is exactly 25.4 mm (NIST SP 811), so 100 mm ÷ 25.4 = 3.937 in.
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84 mm = 3.3071 in
Worked example
84 ÷ 25.4 = 3.3071 inches. On a ruler marked in sixteenths, that is about 3 5/16″; in thirty-seconds, 3 5/16″; in sixty-fourths, 3 5/16″. The nearest 1/16 mark (3 5/16″ = 84.14 mm) is off by 0.14 mm.
84 mm is also 8.4 cm and 0.276 feet.
| Millimeters | Inches | Nearest 1/16 |
|---|---|---|
| 79 mm | 3.1102 | 3 1/8″ |
| 80 mm | 3.1496 | 3 1/8″ |
| 81 mm | 3.189 | 3 3/16″ |
| 82 mm | 3.2283 | 3 1/4″ |
| 83 mm | 3.2677 | 3 1/4″ |
| 84 mm | 3.3071 | 3 5/16″ |
| 85 mm | 3.3465 | 3 3/8″ |
| 86 mm | 3.3858 | 3 3/8″ |
| 87 mm | 3.4252 | 3 7/16″ |
| 88 mm | 3.4646 | 3 7/16″ |
| 89 mm | 3.5039 | 3 1/2″ |
Frequently asked questions
How many inches is 84 mm?
3.3071 inches, about 3 5/16″.
What fraction of an inch is 84 mm?
About 3 5/16″ to the nearest 1/32.