Concrete Cost Calculator: Ready-Mix vs Bagged
Work out how much concrete a slab needs, what it costs delivered by truck, and what the same pour costs in bags. All prices are your own inputs, so the result reflects your area.
A 12 × 24 ft slab poured 4 inches thick needs 3.56 cubic yards of concrete, or about 3.9 with 10% waste, so you would order roughly 4 cubic yards. At $165 per yard that is about $660 before delivery and short-load fees. Enter your own local price.
Your numbers
Result
How concrete is priced
Ready-mix is sold by the cubic yard, and a delivery usually also carries a delivery charge and, for small orders, a short-load fee. Bagged mix is sold by the bag. This calculator turns your slab size into both totals so you can compare them using prices from your own area.
ready-mix total = ordered yards × price per yard + delivery + short-load fee
bags = cubic feet × (1 + waste) ÷ 0.6, at about 0.60 cu ft per 80-lb bag
Worked example
A 12 × 24 ft slab, 4 inches thick: 12 × 24 × (4 ÷ 12) ÷ 27 = 3.56 cubic yards. With 10% waste that is 3.91, and rounded up to the next quarter yard you order 4.00 cubic yards. At an example price of $165 per yard the concrete is $660 before any fees. The same pour in 80-lb bags is about 176 bags.
Cost by slab size
Volume with 10% waste, rounded up to a quarter yard, and the concrete cost at $165 per yard. Change the price to match your supplier.
| Slab | Yards to order | Concrete at $165/yd³ |
|---|---|---|
| 10 × 10 ft, 4 in | 1.50 | $248 |
| 10 × 20 ft, 4 in | 2.75 | $454 |
| 12 × 24 ft, 4 in | 4.00 | $660 |
| 20 × 20 ft, 4 in | 5.50 | $908 |
| 24 × 24 ft, 4 in | 8.00 | $1320 |
When are bags cheaper?
For very small jobs, such as a post, a step or a small pad, bags avoid delivery and short-load charges. As volume grows, mixing dozens of bags by hand is slow and the batches vary, so ready-mix usually wins past a cubic yard or two. Compare both totals above and then call two or three local suppliers for the delivered price on your exact volume.
What this does not include
- Base gravel: use the gravel calculator.
- Reinforcement (rebar or mesh), forms and expansion joints.
- Labor, pump truck or wheelbarrow rental, sealing and finishing.
- Permits, where required.
For other shapes such as footings, columns and steps, use the full concrete calculator. To convert between volume units, see the cubic yard calculator.
Frequently asked questions
How much does concrete cost per cubic yard?
Prices vary by region, mix strength and delivery distance, so use a local quote. The calculator starts with $165 per yard purely as an example.
How much concrete do I need for a 12 x 24 slab?
A 12 × 24 ft slab 4 inches thick needs 3.56 cubic yards, or about 3.9 with 10% waste.
Is it cheaper to mix concrete from bags?
For small jobs it often is, because you avoid delivery and short-load fees. For larger pours, ready-mix usually saves time and gives a more consistent mix.
What is a short-load fee?
A charge many ready-mix suppliers add when an order is below their minimum, to cover the truck trip. Ask your supplier for theirs.
Does the price include labor?
No. The totals cover only the concrete itself. Labor, forms, base, reinforcement and finishing are separate.
Sources and further reading
- NIST Special Publication 811: conversion factors — National Institute of Standards and Technology
These references support the general guidance on this page. The calculator applies the standard formulas shown above to the numbers you enter.
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Related calculators
. Estimates only. Always confirm quantities with your supplier or a qualified contractor before ordering, and add extra for waste and site conditions.