Concrete Bag Calculator (2026) – Quikrete, Sakrete & All Sizes
Find exactly how many bags of concrete you need — 40, 50, 60, 80, and 90 lb — for slabs, post holes, or any custom volume. Includes Quikrete, Sakrete, and store-brand comparisons.
Always add 5–10% — concrete is unforgiving if you run short mid-pour
Bags Needed
Adjust inputs and click Calculate
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40 lb bags
(0.30 ft³ each)
(0.30 ft³ each)
—
50 lb bags
(0.375 ft³ each)
(0.375 ft³ each)
Most Common
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60 lb bags(0.45 ft³ each)
Best Value
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80 lb bags(0.60 ft³ each)
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90 lb bags (0.675 ft³ each) — professional/contractor packs
| Brand | Bag Size | Bags Needed | Est. Cost |
|---|---|---|---|
| Quikrete 5000 | 80 lb | — | — |
| Quikrete General | 60 lb | — | — |
| Sakrete 5000+ | 80 lb | — | — |
| Store Brand | 60 lb | — | — |
*Prices based on 2026 Home Depot/Lowe's averages. Varies by region.
Concrete Bag Yield Reference Table
Each bag size yields a different volume. Use this table to quickly estimate bag counts without a calculator:
| Bag Size | Yield (ft³) | Bags per yd³ | Approx. Price | Best For |
|---|---|---|---|---|
| 40 lb | 0.30 ft³ | 90 bags | $5.50–$7.00 | Small repairs, post holes |
| 50 lb | 0.375 ft³ | 72 bags | $6.50–$8.50 | Post holes, steps, repairs |
| 60 lb | 0.45 ft³ | 60 bags | $7.00–$9.50 | Small slabs, patios under 0.5 yd³ |
| 80 lb | 0.60 ft³ | 45 bags | $9.00–$12.00 | Best value — slabs up to 1 yd³ |
| 90 lb | 0.675 ft³ | 40 bags | $10.00–$13.50 | Contractor use — fewer trips to mixer |
💡 Rule of thumb: One 80 lb bag covers about 0.022 cubic yards. Divide your cubic yard volume by 0.022 to get the number of 80 lb bags needed (before waste factor).
Quikrete vs. Sakrete vs. Store Brand — 2026
| Brand | Popular Product | PSI | Set Time | Notes |
|---|---|---|---|---|
| Quikrete | 5000 Concrete Mix | 5,000 PSI | 24–72 hrs | Most widely available in US. High strength — great for structural work. |
| Quikrete | Fast-Setting Concrete | 4,000 PSI | 20–40 min | Pour dry into hole, add water on top. Ideal for fence posts — no mixing required. |
| Sakrete | 5000+ Concrete Mix | 5,000 PSI | 24–72 hrs | Similar to Quikrete 5000. Available at Home Depot and Lowe's. |
| Sakrete | Maximizer | 4,000 PSI | 24–48 hrs | Larger yield per bag — approximately 20% more volume than standard 80 lb bags. |
| Store Brand | Generic Concrete Mix | 3,000–4,000 PSI | 24–72 hrs | Usually 10–20% cheaper. Fine for non-structural work. Check the PSI label. |
When to Use Bags vs. Ready-Mix
For most projects under 0.75 cubic yards (about 20 cubic feet), bags are practical. Above that, ready-mix is cheaper and produces more consistent results.
- Use bags when: project is under 0.75 yd³, no truck access, working at your own pace, or for fence posts and repairs.
- Use ready-mix when: project exceeds 1 yd³, you need consistent high-strength mix, or labor cost of mixing bags would exceed delivery fee.
- Cost comparison: 80 lb bags cost ~$210–$280/yd³. Ready-mix costs $140–$225/yd³. For a 3 yd³ slab, bags cost ~$650–$840 vs. ready-mix at ~$420–$675 — plus you save hours of mixing labor.
Concrete Bag FAQ
How many 80 lb bags of Quikrete do I need for a 10×10 slab?
A 10×10 slab at 4 inches thick = 33.3 ft³ + 10% waste = 36.7 ft³. At 0.60 ft³ per 80 lb bag: 62 bags. At current prices (~$10/bag), that's ~$620 in bags alone. A ready-mix truck delivery of 1.36 yd³ would cost ~$220–$300 for material — plus a short-load fee. For a project this size, bags vs. ready-mix is close; ready-mix wins on labor.
How many bags of concrete for a fence post?
A standard 10-inch diameter × 24-inch deep fence post hole = 1.09 ft³. One 80 lb bag (0.60 ft³) is not quite enough — use two 80 lb bags per hole, or one 60 lb + one 40 lb bag. For 4×4 posts, a 6-inch diameter hole with one 50 lb bag per post is sufficient. Quikrete Fast-Setting Concrete is the easiest option — pour dry mix around the post and add water directly into the hole, no mixing required.
How many bags of concrete in a yard?
1 cubic yard = 27 cubic feet. Bags needed per cubic yard: 90 × 40 lb bags, 72 × 50 lb bags, 60 × 60 lb bags, 45 × 80 lb bags, or 40 × 90 lb bags. Add 10% for waste, so multiply each number by 1.10 for your actual order quantity.
Is Quikrete the same as regular concrete?
Quikrete is a pre-mixed bagged concrete that contains Portland cement, sand, and aggregate — the same basic ingredients as ready-mix concrete. The difference is that bagged products are batched in a factory and dried; you add water on site. Quikrete 5000 achieves 5,000 PSI — actually stronger than most standard ready-mix residential orders (3,000–3,500 PSI). The trade-off is cost and mixing labor at scale.