Excavation calculator: how many cubic yards of dirt will I dig out?
27.78 cubic yards to haul
22.23 in the ground × 1.25 for common earth (loam) · 3 loads of 10 cu yd · 20.00 if compacted back · for 20 × 10 × 3 ft deep
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3/8 or 10' 6".
27.78 cubic yards to haul
22.23 in the ground × 1.25 for common earth (loam) · 3 loads of 10 cu yd · 20.00 if compacted back
Source: US Army FM 5-434 Earthmoving Operations (June 2000), chapter 1, Table 1-1 Material Volume Conversion Factors, read October 24, 2026. Data sheet (PDF)
Digging a 20 × 10 ft hole 3 ft deep removes 22.23 cubic yards in the ground, which loosens to 27.78 cubic yards of common earth to haul (× 1.25, US Army FM 5-434 Table 1-1): 3 loads of a 10 cubic yard truck.
A worked example
A trench 63 ft long, 1 1/2 ft wide and 2 1/2 ft deep in clay, hauled in a 6 cubic yard truck needs 12.52 cubic yards. 236.25 cu ft is 8.75 cubic yards in the ground; clay swells × 1.43, so 12.52 cubic yards come out, 3 loads of 6. Compacted back, the same clay takes 0.90 × 8.75 = 7.88 cubic yards.
How much does dirt expand when you dig it?
By FM 5-434 Table 1-1, one bank cubic yard becomes 1.11 loose cubic yards of sand or gravel, 1.25 of common earth, 1.43 of clay and 1.50 of blasted rock. Dry clay swells 40%: a cubic yard in the ground fills 1.4 cubic yards loose.
Will the dirt fit back in the hole?
Compacted, a bank cubic yard of common earth or clay takes 0.90 cubic yards and sand or gravel 0.95, so dug soil rolled back in fills a little less than the hole it came from; blasted rock takes 1.30 (FM 5-434 Table 1-1).
What else it is called
Earthmovers measure soil three ways: bank cubic yards (BCY) as it lies, loose cubic yards (LCY) once dug, and compacted cubic yards (CCY). Searched as an excavation calculator, dirt excavation calculator or excavation calculator in cubic yards.
Loose cubic yards by hole and soil
| Hole, L × W × depth | In the ground | Loose, sand or gravel | Loose, common earth | Loose, clay | Loose, blasted rock |
|---|---|---|---|---|---|
| 10 × 10 × 2 ft | 7.41 | 8.23 | 9.26 | 10.60 | 11.12 |
| 20 × 10 × 3 ft | 22.23 | 24.67 | 27.78 | 31.78 | 33.34 |
| 24 × 12 × 4 ft | 42.67 | 47.36 | 53.34 | 61.02 | 64.00 |
| 30 × 20 × 4 ft | 88.89 | 98.67 | 111.12 | 127.12 | 133.34 |
| 40 × 30 × 8 ft | 355.56 | 394.67 | 444.45 | 508.45 | 533.34 |
Cubic yards. Bank to loose: sand or gravel × 1.11, common earth × 1.25, clay × 1.43, blasted rock × 1.50; bank to compacted 0.95, 0.90, 0.90 and 1.30 (US Army FM 5-434, Table 1-1).
Where the numbers come from
- Swell and compaction: US Army FM 5-434, Table 1-1, from bank (in place) to loose: sand or gravel 1.11, loam (common earth) 1.25, clay 1.43, blasted rock 1.50; from bank to compacted: 0.95, 0.90, 0.90 and 1.30. Its text: «the swell of dry clay is 40 percent, which means that 1 cubic yard of clay in the bank state will fill a space of 1.4 cubic yards in a loosened state». Read October 24, 2026. FM 5-434 chapter 1 (PDF)
- The rest is arithmetic: bank cubic yards = length × width × depth in feet ÷ 27; loose = bank × the soil factor; truckloads = loose ÷ truck cubic yards, rounded up.
The factors are averages; FM 5-434 notes that grain size, moisture and compaction move them. Sloped or stepped trench walls dig out more than a square-sided hole of the same floor.
By Javier Miralles · Last updated . How this site is made.
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