Calculator · Sheet T-201
Cut and fill calculator
Net earthwork volume two ways: a grid of cut and fill depths, or cross-section areas by chainage (average end area).
STA 0+120How it works
Grid method. Each grid cell’s volume is its area times the average of the cut or fill depth at its four corners. Cut and fill are averaged separately, so a cell that straddles the daylight line contributes to both. Totals are bank (in-place) volumes for cut and compacted volumes for fill.
Average end area. Between two cross-sections, volume = (A₁ + A₂) ÷ 2 × distance. It is the standard method for linear work such as roads, ditches and embankments, and it slightly overestimates volume where the section changes shape sharply.
Balance. To fill a compacted cubic metre you need 1 ÷ (compaction factor) bank cubic metres of cut. The calculator converts fill to the bank cut it will consume, so “balance” compares like with like.
STA 0+240Assumptions and sources
Compaction factors are average values per bank cubic metre from the U.S. Army earthmoving field manual: clay 0.90, loam 0.90, sand or gravel 0.95, blasted rock 1.301111. Test your actual material; a geotechnical report or Proctor results override these.
Questions people ask
How do you calculate cut and fill volume?
Divide the site into a grid, record the depth of cut or fill at each grid point, and multiply each cell’s area by the average of its four corner depths. For linear work, measure cross-section areas at stations and use the average end area method.
What is the average end area method?
Volume between two cross-sections equals the average of their areas times the distance between them. Sum the segments along the alignment for the total.
Why do cut and fill not balance even when volumes match?
Because ground changes volume when it is dug and recompacted. One bank cubic metre of clay compacts to about 0.90 m³, so you need more cut than fill to balance a site.
Sources
- FM 5-434 Earthmoving Operations, Chapter 1, Tables 1-1 and 1-2U.S. Department of the Army (field manual; hosted copy on GlobalSecurity.org) · FM 5-434 (2000)