Printable reference
Builder's Cheat Sheets
Four reference charts US builders reach for every day. Print the whole set for the shop wall or the truck visor.
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1. Inches to Fractions & Decimals (1/64" to 1")
Bold rows are the marks printed on a standard 1/16" tape. 1" = 25.4 mm exactly.
| Fraction | Decimal in | mm |
|---|---|---|
| 1/64" | 0.015625 | 0.40 |
| 1/32" | 0.03125 | 0.79 |
| 3/64" | 0.046875 | 1.19 |
| 1/16" | 0.0625 | 1.59 |
| 5/64" | 0.078125 | 1.98 |
| 3/32" | 0.09375 | 2.38 |
| 7/64" | 0.109375 | 2.78 |
| 1/8" | 0.125 | 3.17 |
| 9/64" | 0.140625 | 3.57 |
| 5/32" | 0.15625 | 3.97 |
| 11/64" | 0.171875 | 4.37 |
| 3/16" | 0.1875 | 4.76 |
| 13/64" | 0.203125 | 5.16 |
| 7/32" | 0.21875 | 5.56 |
| 15/64" | 0.234375 | 5.95 |
| 1/4" | 0.25 | 6.35 |
| 17/64" | 0.265625 | 6.75 |
| 9/32" | 0.28125 | 7.14 |
| 19/64" | 0.296875 | 7.54 |
| 5/16" | 0.3125 | 7.94 |
| 21/64" | 0.328125 | 8.33 |
| 11/32" | 0.34375 | 8.73 |
| 23/64" | 0.359375 | 9.13 |
| 3/8" | 0.375 | 9.52 |
| 25/64" | 0.390625 | 9.92 |
| 13/32" | 0.40625 | 10.32 |
| 27/64" | 0.421875 | 10.72 |
| 7/16" | 0.4375 | 11.11 |
| 29/64" | 0.453125 | 11.51 |
| 15/32" | 0.46875 | 11.91 |
| 31/64" | 0.484375 | 12.30 |
| 1/2" | 0.5 | 12.70 |
| Fraction | Decimal in | mm |
|---|---|---|
| 33/64" | 0.515625 | 13.10 |
| 17/32" | 0.53125 | 13.49 |
| 35/64" | 0.546875 | 13.89 |
| 9/16" | 0.5625 | 14.29 |
| 37/64" | 0.578125 | 14.68 |
| 19/32" | 0.59375 | 15.08 |
| 39/64" | 0.609375 | 15.48 |
| 5/8" | 0.625 | 15.88 |
| 41/64" | 0.640625 | 16.27 |
| 21/32" | 0.65625 | 16.67 |
| 43/64" | 0.671875 | 17.07 |
| 11/16" | 0.6875 | 17.46 |
| 45/64" | 0.703125 | 17.86 |
| 23/32" | 0.71875 | 18.26 |
| 47/64" | 0.734375 | 18.65 |
| 3/4" | 0.75 | 19.05 |
| 49/64" | 0.765625 | 19.45 |
| 25/32" | 0.78125 | 19.84 |
| 51/64" | 0.796875 | 20.24 |
| 13/16" | 0.8125 | 20.64 |
| 53/64" | 0.828125 | 21.03 |
| 27/32" | 0.84375 | 21.43 |
| 55/64" | 0.859375 | 21.83 |
| 7/8" | 0.875 | 22.22 |
| 57/64" | 0.890625 | 22.62 |
| 29/32" | 0.90625 | 23.02 |
| 59/64" | 0.921875 | 23.42 |
| 15/16" | 0.9375 | 23.81 |
| 61/64" | 0.953125 | 24.21 |
| 31/32" | 0.96875 | 24.61 |
| 63/64" | 0.984375 | 25.00 |
| 1" | 1 | 25.40 |
2. Nominal vs. Actual Softwood Lumber Sizes
Kiln-dried, surfaced four sides (S4S) per the American Softwood Lumber Standard. Board feet are always figured on the nominal size.
| Nominal | Actual (inches) | Actual (mm) | Board ft / linear ft |
|---|---|---|---|
| 1x2 | 3/4" × 1-1/2" | 19 × 38 mm | 0.167 |
| 1x3 | 3/4" × 2-1/2" | 19 × 64 mm | 0.250 |
| 1x4 | 3/4" × 3-1/2" | 19 × 89 mm | 0.333 |
| 1x6 | 3/4" × 5-1/2" | 19 × 140 mm | 0.500 |
| 1x8 | 3/4" × 7-1/4" | 19 × 184 mm | 0.667 |
| 1x10 | 3/4" × 9-1/4" | 19 × 235 mm | 0.833 |
| 1x12 | 3/4" × 11-1/4" | 19 × 286 mm | 1.000 |
| 2x2 | 1-1/2" × 1-1/2" | 38 × 38 mm | 0.333 |
| 2x3 | 1-1/2" × 2-1/2" | 38 × 64 mm | 0.500 |
| 2x4 | 1-1/2" × 3-1/2" | 38 × 89 mm | 0.667 |
| 2x6 | 1-1/2" × 5-1/2" | 38 × 140 mm | 1.000 |
| 2x8 | 1-1/2" × 7-1/4" | 38 × 184 mm | 1.333 |
| 2x10 | 1-1/2" × 9-1/4" | 38 × 235 mm | 1.667 |
| 2x12 | 1-1/2" × 11-1/4" | 38 × 286 mm | 2.000 |
| 4x4 | 3-1/2" × 3-1/2" | 89 × 89 mm | 1.333 |
| 4x6 | 3-1/2" × 5-1/2" | 89 × 140 mm | 2.000 |
| 4x8 | 3-1/2" × 7-1/4" | 89 × 184 mm | 2.667 |
| 4x10 | 3-1/2" × 9-1/4" | 89 × 235 mm | 3.333 |
| 4x12 | 3-1/2" × 11-1/4" | 89 × 286 mm | 4.000 |
Rule: under 2" nominal subtract 1/4"; 2"–6" subtract 1/2"; 8" and wider subtract 3/4".Board feet calculator →
3. Material Densities & Coverage per Cubic Yard
Typical in-place weights — moisture and supplier gradation change them, so check the ticket when buying by the ton. Coverage is the same for any material: 1 yd³ = 27 cu ft = 324 sq ft at 1" deep.
| Material | lbs / yd³ | Tons / yd³ | Typical range | Bags per yd³ | Typical depth |
|---|---|---|---|---|---|
| Concrete (normal weight) | 4,050 | 2.03 | 3,900–4,100 lb | 45 × 80 lb · 60 × 60 lb | 4"–6" slabs |
| Pea gravel (3/8") | 2,700 | 1.35 | 2,500–2,900 lb | 54 × 0.5 cu ft | 2"–3" paths, 4" play areas |
| Crushed stone #57 (¾"–1") | 2,800 | 1.40 | 2,500–3,000 lb | 54 × 0.5 cu ft | 4" driveway top, drainage |
| Topsoil (screened) | 2,200 | 1.10 | 1,800–2,600 (wet = heavier) lb | 36 × 0.75 cu ft | 4"–6" new lawn |
| Mulch (shredded hardwood) | 600 | 0.30 | 400–800 lb | 13.5 × 2 cu ft | 2"–3" beds |
Coverage of 1 cubic yard by depth
| Depth | 2" | 3" | 4" | 6" |
|---|---|---|---|---|
| Sq ft covered | 162 sq ft | 108 sq ft | 81 sq ft | 54 sq ft |
4. Roof Pitch Angles & Rafter Multipliers
Multiply the run by the common-rafter multiplier for rafter length. Hip/valley length per foot of common run is √(rise² + 288).
| Pitch | Angle | Grade | Common multiplier | Common rafter / ft run | Hip-valley / ft run |
|---|---|---|---|---|---|
| 1/12 | 4.76° | 8.3% | 1.0035 | 12-1/16" | 17" |
| 2/12 | 9.46° | 16.7% | 1.0138 | 12-3/16" | 17-1/16" |
| 3/12 | 14.04° | 25.0% | 1.0308 | 12-3/8" | 17-1/4" |
| 4/12 | 18.43° | 33.3% | 1.0541 | 12-5/8" | 17-7/16" |
| 5/12 | 22.62° | 41.7% | 1.0833 | 13" | 17-11/16" |
| 6/12 | 26.57° | 50.0% | 1.1180 | 13-7/16" | 18" |
| 7/12 | 30.26° | 58.3% | 1.1577 | 13-7/8" | 18-3/8" |
| 8/12 | 33.69° | 66.7% | 1.2019 | 14-7/16" | 18-3/4" |
| 9/12 | 36.87° | 75.0% | 1.2500 | 15" | 19-3/16" |
| 10/12 | 39.81° | 83.3% | 1.3017 | 15-5/8" | 19-11/16" |
| 11/12 | 42.51° | 91.7% | 1.3566 | 16-1/4" | 20-1/4" |
| 12/12 | 45.00° | 100.0% | 1.4142 | 17" | 20-13/16" |
| 13/12 | 47.29° | 108.3% | 1.4743 | 17-11/16" | 21-3/8" |
| 14/12 | 49.40° | 116.7% | 1.5366 | 18-7/16" | 22" |
| 15/12 | 51.34° | 125.0% | 1.6008 | 19-3/16" | 22-5/8" |
| 16/12 | 53.13° | 133.3% | 1.6667 | 20" | 23-5/16" |
| 17/12 | 54.78° | 141.7% | 1.7341 | 20-13/16" | 24" |
| 18/12 | 56.31° | 150.0% | 1.8028 | 21-5/8" | 24-3/4" |
Reference values only — verify against manufacturer data and your local code. Printed from buildmath.online/cheat-sheets/.