Concrete Calculator
You know the volume. This page decides how to buy it: bags or a ready-mix truck — and finds the exact volume where the cheaper route changes.
Concrete Calculator
Results recalculate instantly on every keystroke. Nothing you type is transmitted.
What this result does not account for
- Material prices only — no pump, finishing or labour.
- Fee model is binary: full truck or fee, no per-yard short rates.
- Yield assumes proper water ratio; soupy mix yields more, weaker.
In short: 6.518519 yd³ as 80-lb bags: 294 bags, $2,352.00, 11.76 tons to hump. The same yards from a truck at $175 plus a $150 short-load fee: $1,290.74. The crossover sits at 0.810811 yd³ — above it, the truck wins on price and on your back.
Formula
80-lb bags = ⌈feet³ ÷ 0.60⌉ (45.0 per yard)
bag total = bags × bag price
truck total = yards × rate + short-load fee under a truck
crossover = fee ÷ (45 × bag price − truck rate)
[('yield', '0.60 ft³ per 80-lb sack, manufacturer-published'), ('the fee', "the truck's fixed dispatch cost, under capacity"), ('crossover', 'the volume where the cheaper route changes'), ('honesty', 'bags carry hidden labour the truck carries in price')]
Worked Example
- Convert the volume to 80-lb sacks at the exact 45-per-yard yield.
- Price the bag route and its physical weight and pallets.
- Price the truck route, applying the fee only under capacity.
- Declare the winner and the cents between the routes.
- Solve the crossover volume and show how it moves with bag price.
The spine job's 6.518519 yd³: 294 × 80-lb bags = $2,352.00 and 11.76 tons of sacks, against $1,290.74 from the truck ($175 × 6.518519 + $150). The truck wins by $1,061.26 — and the crossover says any pour above 0.810811 yd³ (21.89 ft³) belongs to the truck at these prices.
Strengths & Limits Of This Model
Where this engine is strong
- Crossover volume solved, not guessed
- Physical weight and pallets priced alongside dollars
- Both sack sizes compared on cost AND mixes
Where it stops
- No pump or finishing add-ons
- Two-point fee model
Practical Use Cases
Route decision
Bags or truck, on your prices, not folklore.
Small pours
Post holes and pads where the fee decides.
Budget quotes
Both totals before you call the plant.
Delivery planning
Pallets and tonnage for a bag delivery.
Price shopping
How the crossover moves when quotes change.
Methodology & Editorial Standards
Bag counts use the manufacturer yield table (0.60/0.45/0.30 ft³, exact 45/60/90 per yard) rounded up to whole sacks. The truck total applies the short-load fee only when the order is under the entered capacity. The crossover solves fee = yards × (45 × bag price − truck rate) and is reported with its $7 and $9 neighbours so the verdict is a range, not a point. Zero or negative volumes are refused.
Computation runs in IEEE-754 double precision at full internal precision; rounding to two decimal places occurs strictly at the display layer, so no cumulative drift enters the result. All monetary outputs use accounting presentation — grouped thousands, two decimals, negatives in parentheses — so figures can be transcribed directly into a model or working paper. Division-by-zero and out-of-domain inputs return an em-dash rather than a misleading number.
This engine was reconciled against an independent reference implementation and hand-verified for the worked example above before release. Our full five-stage review process is published on the About Us page.
Disclaimer. This calculator is provided for informational and modelling purposes only and does not constitute financial, tax, legal, medical, or engineering advice. Verify all figures with a qualified professional before acting on them.
Concrete Calculator — 10 Expert FAQs
10 analyst-written answers to the questions practitioners actually ask — optimised for voice and answer-engine retrieval.
How many 80-lb bags of concrete make a cubic yard?
Exactly 45. An 80-lb sack yields 0.60 cubic feet per the manufacturer's data sheet, and a yard is 27 cubic feet: 27 ÷ 0.60 = 45.0. The 60-lb sack yields 0.45 ft³, so 60 of those make a yard.
Is it cheaper to use bags or ready-mix concrete?
Above roughly one cubic yard, the truck — every time. Bags price near $315-405 a yard against a delivered $125-195, so the only question is whether your pour is small enough that the short-load fee flips it. At 2026 reference prices the flip sits at 0.81 yd³.
What is a short-load fee?
The supplier's fixed dispatch charge for orders under a full truckload — typically 8-10 yards, fee $40-150. It is why a 2-yard pour can cost nearly a 5-yard pour: the truck costs the same to send regardless of how full it leaves.
How much does a yard of ready-mix cost in 2026?
The delivered national band is $125-195 per cubic yard, with most standard 3,000-4,000 psi residential mix between $140 and $180. High-cost metros run $200-220. This page's $175 reference sits mid-band; enter your local quote.
How much does a bag of concrete cost?
80-lb sacks averaged $7-9 at US retailers in 2026, with $8 the working mid-point; 60-lb around $5.75-7. Multiply by 45 sacks and the bag route prices a yard before you mix the first one.
How many bags come on a pallet?
About 40 for the 80-lb sack, though it varies by supplier. The 294-bag spine order is 7.35 pallets — eight, in practice — which is the moment most DIY plans become a delivery order.
How strong is bagged concrete?
The leading pre-blend is a 4,000 psi mix at 28 days — stronger than most residential pours need and comparable to a truck's 4,000-psi order. Bagged is not weak; it is expensive per yard and heavy per worker.
How much water does an 80-lb bag need?
Roughly 3-4 quarts per sack for the standard pre-blend — enough for workability, never enough for soupy. Extra water is the classic strength killer: it raises slump and cuts psi. Follow the sack, not the hose.
How long does concrete take to cure?
Walkable in 24-48 hours, and spec strength at 28 days, with about 70% of it in place by day 7. Keep it damp for the first week; curing is a moisture schedule, not a drying one.
Does this include the cost of mixing labour?
No — and that is the bag route's hidden invoice. The truck's price includes its mixer; your arms do not come priced. When the routes are within a small margin, the labour difference decides it, not the receipts.