How we calculate
Every result on CubicYardage comes from the same transparent math, computed in your browser. We show our work here so you can check it.
Volume
All shapes reduce to a volume in cubic feet: slabs, footings, walls and curbs are length × width × thickness; columns and post holes are π × radius² × height; stairs are a stack of rectangular blocks summed over each step.
Waste & ordering
We multiply by (1 + waste%) and round the order up to the nearest half cubic yard, matching how ready-mix suppliers take orders.
Bag counts
Bag yields are the published set-concrete volumes: 80 lb = 0.60 ft³, 60 lb = 0.45 ft³, 50 lb = 0.375 ft³, 40 lb = 0.30 ft³. Bag count rounds up.
Mix ratio
The mix ratio calculator proportions a target volume into cement, sand and aggregate. Dry ingredients bulk up to about 1.54× the finished wet concrete volume (a standard mix-design figure), and a 94 lb bag of Portland cement is taken as roughly 1 ft³ loose. Ratios are by volume; structural work should follow a specified mix design.
Bulk material densities
The material calculators convert volume to weight using these planning densities (tons per cubic yard), corroborated across published material charts. They vary with moisture, gradation and compaction, so each is editable.
| Material | Tons / cu yd |
|---|---|
| Gravel / crushed stone | 1.5 (range 1.4–1.7) |
| Topsoil | 1.1 (wetter is heavier) |
| Mulch | 0.4 |
| Sand (dry) | 1.3 (wet ~1.6) |
| Asphalt | 2.0 |
Weight
Normal-weight concrete is about 150 lb/ft³, or roughly 4,050 lb (about 2 tons) per cubic yard.
Cost comparison
The bags-vs-ready-mix tool compares 80-lb bag cost against a ready-mix order (per-yard rate + delivery + short-load fee for small orders). Prices are editable because they vary by market; defaults reflect 2026 U.S. national averages.
Default prices & sources
The cost estimator ships with editable 2026 U.S. national-average defaults, reviewed 2026-06. There is no single authoritative national price feed for ready-mix or aggregate, so these are midpoints of published industry sources and are starting points only — local prices vary by 30% or more, so edit them and confirm with a supplier quote.
| Material | Default | Basis (2026 sources) |
|---|---|---|
| Ready-mix concrete | $165 / cu yd | ConcreteNetwork $160–195; slabcalc / costflowai $125–175; Constructem ~$155 |
| Delivery fee | $60 | Angi: $5–10/mile beyond base radius + fuel surcharge |
| Short-load fee (under 4 yd) | $80 | Angi $40–60/yd; HomeGuide ~$53/yd + mixing charge |
| 80 lb concrete bag | $6.75 | Home Depot 2026 pricing ~$6.78/bag |
| Rebar #4 (1/2") | $0.75 / ft | bhumicalculator $0.55–0.85; HomeGuide $0.40–1.25; LatestCost $0.60–2.80 |
| Crushed stone base | $40 / ton | Bovees $25–55/ton; BuildEstimatory $20–35/ton |
We plan to keep these defaults drifting with the U.S. Bureau of Labor Statistics producer price indices for cement and steel over time; until then, the review date above reflects the last manual check.
These are planning estimates assuming clean geometry. They exclude over-excavation, sub-base irregularities and structural requirements. For anything load-bearing, consult an engineer and your local code.