Estimate the number of 40, 50, 60, 80 or 90 lb concrete bags for a slab, footing, post hole or wall fill — with total weight, pallet count and reverse-coverage mode for bags you already have.
12 5/8, 12-5/8, or 12.625.| Bag | Yield ft³ | Bags | Total weight |
|---|---|---|---|
| 40 lb | 0.30 | 123 | 4,920 lb |
| 50 lb | 0.375 | 98 | 4,900 lb |
| 60 lb | 0.45 | 82 | 4,920 lb |
| 80 lb | 0.60 | 62 | 4,960 lb |
| 90 lb | 0.675 | 55 | 4,950 lb |
Bag yields · pallet · prices (override)
Quikrete and Sakrete print slightly different yields per bag. Override here if your label disagrees.
Bag yields at a glance
Manufacturer-quoted yields from Quikrete, Sakrete and Sika datasheets. Cross-check the printed yield on your bag — Type-S vs high-strength formulas drift by 2–3% on the same bag weight.
| Bag | Yield (cu ft) | Bags per cu yd | Pallet weight (typ.) |
|---|---|---|---|
| 40 lb (18 kg) | 0.30 | 90 | 80 bags = 3,200 lb |
| 50 lb (23 kg) | 0.375 | 72 | 64 bags = 3,200 lb |
| 60 lb (27 kg) | 0.45 | 60 | 56 bags = 3,360 lb |
| 80 lb (36 kg) | 0.60 | 45 | 42 bags = 3,360 lb |
| 90 lb (41 kg) | 0.675 | 40 | 36 bags = 3,240 lb |
Pallet counts vary by retailer and region — Home Depot and Lowes often ship 56-bag mixed pallets regardless of label weight, which is why the calculator lets you override bags per pallet.
Worked example — 10 × 10 ft patio at 4″
This is the fifth Quick Start preset. The math chain that produces 62 × 80-lb bags:
- Convert thickness to feet:
4 / 12 = 0.333 ft - Base volume:
10 × 10 × 0.333 = 33.33 cu ft(= 1.234 cu yd) - Add 10% slab waste:
33.33 × 1.10 = 36.67 cu ft - Round up to whole 80-lb bags:
ceil(36.67 / 0.60) = ceil(61.11) = 62 bags - Total weight:
62 × 80 lb = 4,960 lb(≈ 2,250 kg) — about 1.5 standard pallets
Same scope in 60-lb bags = ceil(36.67 / 0.45) = 82 bags; in 40-lb bags = 123 bags. The lighter-bag option saves your back per lift but adds more trips between truck and forms.
Three modes — when to use which
- Dimensions → bags
- You have a hole, a slab outline, or a wall to fill. Pick the shape, enter L × W × T (or diameter × depth for round footings), and the calculator returns recommended bag counts across all five sizes plus total weight.
- Volume → bags
- You already worked out the cubic yards (or your supplier quoted you a yardage). Type the volume and the calculator splits it across all bag sizes simultaneously — useful when you are price-shopping different bag weights at different retailers.
- Bags → coverage
- You bought 30 bags from a clearance pallet. Mode C tells you how many square feet you can pour at 2″, 4″, and 6″ thicknesses, plus the total weight you are about to mix. This is the inverse direction the master concrete calculator does not handle.
Common questions
Why round up on every bag size?
There are no half bags — once a bag is opened it sets within hours. Pros stage one extra bag per pallet for the inevitable spillage at the wheelbarrow corner and the touch-up after the screed pull. The calculator already adds a configurable waste percentage; the safety-bag toggle adds one more for small pier and post holes where the math lands awkwardly close to a bag boundary.
Are 90-lb bags worth it over 80-lb?
On per-cubic-foot pricing, yes — 90-lb bags are typically 8–12% cheaper per yield foot at big-box retailers. On lift weight they cross a real threshold: a 90-lb bag exceeds the 50-lb OSHA recommended-handled limit for a single worker by 80%, and bags on the bottom of a 36-bag pallet can crack under their own weight if stored damp. For a one-day weekend pour, 80-lb is the standard. For a buy-once-pour-once stockpile, 60-lb is gentler on the back and cheaper to return if mis-counted.
What does pallet count actually mean for delivery?
Most bagged-concrete deliveries arrive curbside on a pallet. Curbside drop with a pallet jack needs paved access; lift-gate trucks add $50–80; rural or unpaved drop reverts to the driver hand-stacking each bag (slow, sometimes refused). One pallet of 80-lb bags weighs ~3,360 lb — that is too much for a half-ton pickup bed, fine for a three-quarter ton, requires a one-ton or trailer for two pallets. The pallet count from the calculator is the number to discuss with the dispatcher, not the truck driver.
Estimator only. Bag yields drift by 0–3% in real conditions (subgrade absorption, bag residue, finish flatness). For pours where the cubic-yard reading matters more than the bag count — patios over 100 sq ft, driveways, footings — switch to the main concrete calculator for the bags-vs-ready-mix decision and truckload estimate. For volume reconciliation between supplier slips and your scope, use the cubic yards to cubic feet converter.
