60 bags of 60 lb mix, or 45 bags of 80 lb. The numbers come straight off Quikrete and Sakrete data sheets — a 60 lb bag yields 0.45 ft³ once mixed, and 80 lb yields 0.60 ft³, so a cubic yard (27 ft³) takes 27 / 0.45 = 60 bags or 27 / 0.60 = 45 bags. Both mixes meet ASTM C387 and behave identically by volume; the only reason to pick one over the other is bag handling and per-cubic-foot cost in your zip code.
Run the same math for any partial yardage on the concrete yardage calculator — it returns the bag count for both sizes alongside the practical ready-mix order, which is the more useful comparison when you're deciding whether to drive to the store or call a dispatcher.
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Hi, I'm the SiteworkMath assistant. I answer questions about the calculators and guides on this site — concrete yardage, topsoil, mulch, tile, and decking material math. I'm not a structural engineer or a licensed contractor; I'm a calculator built around the math that James Wu — Chicago-area flipper — uses on his own jobs. For structural decisions (joist sizing, beam spans, footing depth in your soil + climate, anything that needs a permit) talk to a licensed structural engineer or your local building department.
How pros actually do this
Above 1 yd³ I'd order ready-mix every time — bags above that capacity is a back injury looking for a wheelbarrow. A cubic yard is 45 of the 80 lb bags, which is 3,600 lb of concrete you have to lift twice (off the pallet, into the mixer) and finish before the first batches set. On a 1.48 yd³ basement slab — roughly 67 bags — that works out to 5,360 lb of total bag-handling for one slab, and you've still got to finish the surface inside the 90-minute workable window before the early batches stiffen.
The actual cutover where bagged stops being cheaper isn't 1 yd³ though — it's the residential ready-mix delivery minimum, which most Chicago-suburb plants set somewhere between 1 and 3 yd³. Below the minimum the dispatcher tacks on a short-load fee of $40-60 per cubic yard under the threshold per NRMCA CIP 31, which can easily double the per-yard price on a 1-2 yd³ pour. That's the gap where bagged still wins on cost — even if it loses on labor.
The flip that pinned this for me was a 10×12 basement slab on a Chicago-suburb gut rehab — 1.48 yd³ exact. The closest plant's minimum was 3 yd³, which would have meant ordering nearly twice the concrete or paying the short-load fee. Picked up 67 bags of Sakrete High-Strength from the Home Depot in the suburbs Saturday morning, ran two 9-cubic-foot mixers in parallel with my brother shoveling and me screeding, poured by 2 pm. The math was right; the order was right. Solo it would have been a 6 pm finish and a wrecked back on Sunday.
On the bag-size question, I default to 80 lb. The argument for 60 lb is purely lifting — fewer pounds per bag, less back strain. But you're also handling 33% more bags for the same yardage, and at typical retail the 60 lb is barely cheaper per cubic foot anyway. Unless someone on the crew physically can't lift 80 lb comfortably, 80 lb is the call. Pulling 90 bags off a pallet is longer than pulling 67.
The bag math, line by line
The 60 lb bag.
A 60 lb bag of standard concrete mix yields 0.45 ft³ of poured concrete once mixed with the recommended water — that's the printed yield on Quikrete Concrete Mix #1101 and on Sakrete's equivalent. Divide a cubic yard's 27 ft³ by 0.45 and you get exactly 60 bags. For partial yardages, take your cubic-yard figure, multiply by 60, and round up to the next whole bag. A 0.5 yd³ post-hole footing is ceil(0.5 × 60) = 30 bags.
The 80 lb bag.
An 80 lb bag yields 0.60 ft³ per the same data sheets. Divide 27 / 0.60 and you get exactly 45 bags per cubic yard. Same partial-yardage rule: multiply your cubic-yard figure by 45 and round up. The 1.48 yd³ slab on the SiteworkMath homepage Material Order Cushion lands at ceil(1.48 × 45) = 67 bags.
Cost per cubic foot, both sizes.
At typical retail (2025 prices, big-box stores in the Chicago metro): an 80 lb bag at $7 is $11.67/ft³ ($7 / 0.60), so a cubic yard runs about $315. A 60 lb bag at $5.50 is $12.22/ft³ ($5.50 / 0.45), so the same cubic yard runs about $330. The spread is small enough that local pricing flips the answer regularly — and both sizes cost roughly twice as much per yard as ready-mix delivered above the residential minimum, which in the Chicago suburbs runs $150-200 per yard plus delivery.
The cubic-yards-to-bags table
Run the row that matches your slab volume. The 80 lb column is ceil(yd³ × 45); the 60 lb column is ceil(yd³ × 60).
| Cubic yards | 60 lb bags | 80 lb bags |
|---|---|---|
| 0.25 | 15 | 12 |
| 0.50 | 30 | 23 |
| 1.00 | 60 | 45 |
| 1.48 (homepage example) | 89 | 67 |
| 1.75 | 105 | 79 |
| 2.00 | 120 | 90 |
| 3.00 | 180 | 135 |
The 1.48 yd³ row matches the SiteworkMath homepage Material Order Cushion — 10 ft × 12 ft × 4″ residential interior slab, the most common piece of concrete on a flip.
Run the math yourself
Type your slab dimensions. The calculator below is the same one used on the cluster anchor page; it returns the cubic-yard volume, both bag-count options, and the practical ready-mix order with the residential-minimum warning.
Where this number breaks down
The bag-count math is clean, but a few real-world gotchas put it on the wrong side of the order:
- Bag yields are nominal.Real-world yield drops slightly when extra water is mixed for workability — common when a crew mixes a little wet to keep the wheelbarrow runs flowing. That extra water displaces aggregate and your effective cubic-foot yield can come in 3-5% short. If the pour is tight to the math, buy one or two extra bags by hand; don't cushion the bag count AND the cubic-yard count or you'll over-order.
- The 60 lb vs 80 lb pricing flips by region.Big-box retail in the Chicago metro tends to favor 80 lb on per-cubic-foot cost, but I've seen the inversion in Michigan and at smaller independent yards where the 60 lb is loss-leader-priced for foot traffic. Check the per-cubic-foot math at your actual store — bag price ÷ yield (0.45 or 0.60) gives the comparable number.
- The bagged-vs-ready-mix inversion at ~3 yd³.Below the residential ready-mix delivery minimum (typically 3 yd³ in the Chicago suburbs), bagged is cheaper than ready-mix even though it's more labor — the short-load fee under threshold is what tips the math. Above 3 yd³ ready-mix wins on both cost AND labor. The awkward middle is right around 1.5-2 yd³ where the answer depends on which supplier you call.
- Solo pour vs. team pour.67 bags solo is a long Saturday — you're mixing, hauling, screeding, and finishing alone, all inside the 90-minute workable window before the early batches stiffen. With two people splitting mix-and-haul vs. screed-and-finish, the same pour wraps mid-afternoon. Don't plan a solo bagged pour above ~30 bags unless you've done one before.
- Fast-setting bags are different.Quikrete Fast-Setting #1004-50 reports the same nominal yield but mixes and sets differently — about 20-40 minutes of workable time vs the 90 minutes you have on standard mix. The yield math doesn't change; the pour-day math does. Don't mix more than you can place in 15 minutes.
- High-strength bags = same yield, different PSI. Sakrete High-Strength and Quikrete High-Strength hit 0.45/0.60 ft³ yields just like standard mix. The difference is mix design and cost — 5,000+ PSI rating vs 4,000, with a small premium per bag. Don't overpay for high-strength on a residential slab where standard 4,000 PSI is plenty.
Frequently asked
How many 80 lb bags of concrete equal a yard?
45 bags. The number comes off the Quikrete Concrete Mix #1101 data sheet — an 80 lb bag yields 0.60 cubic feet once mixed with water, and a cubic yard is 27 ft³, so 27 / 0.60 = 45. Sakrete High-Strength matches the same yield and meets ASTM C387. For partial yards, multiply your cubic-yard figure by 45 and round up: a 1.48 yd³ slab takes Math.ceil(1.48 × 45) = 67 bags.
How many 60 lb bags of concrete equal a yard?
60 bags. A 60 lb bag yields 0.45 ft³ per the same Quikrete and Sakrete data sheets, so 27 / 0.45 = 60 bags per cubic yard. Same math for partials — multiply yardage by 60, round up. Most flippers I know default to 80 lb bags because you're handling fewer of them; the 60 lb stack is the call when the labor pool can't lift heavier comfortably.
Are 60 lb or 80 lb bags cheaper per cubic foot?
80 lb bags are slightly cheaper per cubic foot at typical retail. At $7 a bag, 80 lb mix runs about $11.67/ft³ ($7 / 0.60 ft³); at $5.50 a bag, 60 lb mix runs about $12.22/ft³ ($5.50 / 0.45 ft³). Per cubic yard that's roughly $315 vs $330 — close enough that local pricing flips the answer regularly. Check your local Home Depot or Menards before committing.
At what cubic yardage should I switch from bagged to ready-mix?
Above 1 cubic yard I'd order ready-mix every time — bags above that capacity is a back injury looking for a wheelbarrow. The catch is the residential delivery minimum: most Chicago-suburb plants set it between 1 and 3 yd³, and ordering under triggers a short-load fee of $40-60 per yard under threshold (NRMCA CIP 31). Below the minimum, bagged is the cheaper call even though it's more labor. Right around 1.5-2 yd³ is the awkward middle where the answer depends on your supplier.
Do high-strength concrete bags yield the same volume as standard?
Yes — Sakrete High-Strength and Quikrete High-Strength bags hit the same nominal yields (0.45 ft³ for 60 lb, 0.60 ft³ for 80 lb) as standard mix. The difference is PSI rating (5,000+ vs 4,000) and mix design, not volume. Where yields diverge is fast-setting bags (Quikrete Fast-Setting #1004-50 reports the same yield but mixes differently) and specialty mixes — always check the bag's printed yield rather than assuming.
How much does a yard of bagged concrete cost in the Chicago suburbs?
At typical big-box retail in 2025, a cubic yard of 80 lb bagged concrete is about $315 (45 bags × $7) and a cubic yard of 60 lb is about $330 (60 bags × $5.50). Ready-mix delivered in the Chicago suburbs runs $150-200 per yard plus delivery — roughly half the price-per-yard, before short-load fees. The trip-to-the-store labor and the wheelbarrow day on a bagged pour aren't priced in.
Related guides
- Concrete yardage for a slab →
- Concrete yardage for footings →
- Concrete yardage for steps and stairs →
- Concrete yardage for a circle (post holes) →
Once you've picked a bag size, the next decision is the cubic yardage itself — getting the slab volume right before you start counting bags. How to figure concrete yardage for a slab walks the four steps end to end.
By James Wu. Bag-count derivations are site arithmetic from the 27 ft³ / yd³ conversion and bag-yield constants. Bag yields trace to Quikrete Concrete Mix #1101 data sheet and Sakrete High-Strength Concrete Mix, both meeting ASTM C387. Ready-mix delivery and short-load guidance from NRMCA CIP 31 — Ordering Ready Mixed Concrete. Engine logic in lib/sitework/concrete.ts and lib/sitework/constants.ts. Not structural-engineering advice — for code questions or structural design, work with a licensed engineer or your local building inspector. Full methodology.