1:2:4 Concrete Mix Calculator

Quick answer

1:2:4 Concrete Mix Calculator: per yd³ wet: ~5.9 bags cement (round to 6), 11.9 ft³ sand (0.44 yd³), 23.8 ft³ stone (0.88 yd³), ~30–36 gal water as a starting range across those cement bags.

1:2:4 Concrete Mix Calculator: How the numbers are built

Wet 27 ft³ × 1.54 ≈ 41.6 ft³ dry. Parts 1+2+4 = 7. Cement = 41.6/7 ≈ 5.9 ft³ ≈ one 94 lb bag per ft³. Sand = 2× that; stone = 4× that. This is a nominal batch, not a certified strength.

1:2:4 Concrete Mix Calculator: Scaling

Halve for half a yard. Or calculate wet yards first on the yard calculator and run the mix ratio calculator. For half a yard expect about 3 cement bags after rounding — still buy whole bags.

When to skip site mixing

Past roughly a yard, ready-mix usually wins on consistency and labor. Read ready-mix or bags if you were about to shovel three yards by hand.

Batching tips for 1:2:4

Use one container for parts. Damp sand bulks differently than bone-dry sand — consistent moisture matters. Add water gradually. Place and finish before the batch stiffens. For more than about a yard, strongly consider ready-mix instead of heroic wheelbarrow math.

Per half yard cheat sheet

About 3 bags of 94 lb cement, 6 ft³ sand, 12 ft³ stone, and roughly 15–18 gallons of water as a starting range. Still round cement bags up. Still treat it as nominal, not certified psi.

Field notes to keep handy

Measure to the outside of the forms. Convert every side to the same unit before you multiply. Apply waste after you sum every piece of the job, then round once for the plant.

Bag counts always round up because a partial bag is still a whole bag at the store. Compare that total with a delivered price when short-load fees show up on the quote.

Normal-weight planning density here is 150 pounds per cubic foot unless you switch it. Lightweight mixes and specialty bags can differ — read the ticket or the label when they do.

Field notes to keep handy

Measure to the outside of the forms. Convert every side to the same unit before you multiply. Apply waste after you sum every piece of the job, then round once for the plant.

Bag counts always round up because a partial bag is still a whole bag at the store. Compare that total with a delivered price when short-load fees show up on the quote.

Normal-weight planning density here is 150 pounds per cubic foot unless you switch it. Lightweight mixes and specialty bags can differ — read the ticket or the label when they do.