Find out what your concrete job will really cost. Type the slab size and your local prices, the calculator compares ready-mix (truck) with bags and tells you the cheaper way. Quick answer: for a 10 × 10 slab, ready-mix is usually cheaper once delivery is added, bags win only on small jobs.
Step 1: Type the slab's length, width and thickness.
Step 2: Type the prices you were quoted, ready-mix per cubic yard plus its delivery fee, and/or the price of one bag. You can fill one side or both.
Step 3: Press Calculate. If you filled both prices, the calculator also tells you which way is cheaper.
Amount first: the calculator finds the concrete the same way as our Concrete Calculator, volume with 10% extra. A 10 × 10 slab at 4 inches needs 1.36 cubic yards to order, or 62 bags of 80 lb.
Ready-mix cost = yards to order × price per yard, rounded to the nearest dollar, + delivery fee. The math uses the yards at full precision, only the display is rounded. Example: a 10 × 10 slab is 1.358 yards at full precision (shown as 1.36): 1.358 × $150 = $203.70, + $75 delivery = $278.70 → $279.
Bags cost = bags to buy × price per bag. Example: 62 × $5.50 = $341.
So for this slab, ready-mix is cheaper by about $62: and the truck does the mixing for you. For very small jobs, bags usually win, because there is no delivery fee.
Money rule on this page: every money total is rounded to the nearest dollar, the way a shop quote looks. The math uses the full number of yards, not the rounded one shown.
Ready-mix at $150 per cubic yard + $75 delivery; 80 lb bags at $5.50 each. All slabs 4 inches thick. Totals rounded to the nearest dollar. Small ready-mix orders often add a short-load fee, not included here.
| Slab size | Ready-mix total | Bags total | Cheaper way |
|---|---|---|---|
| 5 × 5 ft | $126 | $88 (16 bags) | Bags |
| 10 × 10 ft | $279 | $341 (62 bags) | Ready-mix |
| 12 × 12 ft | $368 | $484 (88 bags) | Ready-mix |
| 10 × 20 ft | $482 | $677 (123 bags) | Ready-mix |
| 20 × 20 ft | $890 | $1,348 (245 bags) | Ready-mix |
1. Forgetting the delivery fee. Ready-mix is priced per yard, but the truck ride costs extra, often $50–$150. Always add it before comparing with bags.
2. Not counting your own mixing work. 62 bags is heavy, slow work. Bags can look cheaper on paper and still cost you a full day.
3. Using a price from another city. Concrete prices change a lot by area. Use a local quote, not a national average you saw online.
4. Wrong thickness. A 6-inch slab uses 50% more concrete than a 4-inch one. Check the thickness before you price the job.
For small jobs (under about half a cubic yard), bags are usually cheaper because there is no delivery fee. For a full slab, ready-mix usually wins, in the example above it saves $62 on a 10 × 10 slab, and the bigger the slab, the bigger the saving.
Many ready-mix companies add a fee when you order a small amount (often under 3–4 cubic yards), because the truck still makes the trip. Ask about it when you get your quote, and add it to the delivery fee box if they charge one.
10% extra, the same as our Concrete Calculator. Running short in the middle of a pour costs far more than a little leftover.
No. This is material cost only, concrete itself. Hiring someone to form, pour and finish the slab is a separate labor cost.
Prices change by city, season and how busy local companies are. This calculator uses the prices YOU type in, get one or two local quotes and use those numbers.