Find how many bags of concrete mix you need in 40, 50, 60, and 80 lb sizes.
01 / PROJECT DIMENSIONS↙
Length
Width
Waste %%
Change any measurement to update your estimate.
02 / YOUR MATERIAL ESTIMATE
You need approximately
1.23 cubic yards
33.33 ft³ of concrete
With 5% waste: 1.3 cubic yards(recommended when ordering)
40 lb bags
112 bags
50 lb bags
89 bags
60 lb bags
75 bags
80 lb bags
56 bags
You need
1.23 cubic yards
Enter your slab or footing dimensions and the tool returns the bag count for each size.
This view breaks the pour into 40, 50, 60, and 80 lb bag counts so you can compare. Remember the tipping point: past about 50 bags, ready-mix delivery is cheaper and avoids cold joints between batches.
Why order extra? The headline number is the exact material your project
needs. When you actually order, add about 5–10% on top — the “with 5% waste” figure
in the result is a safe starting point. That margin covers what you lose to compaction,
cuts around edges and corners, and ordinary spillage during handling. It is cheaper to have
a little left over than to stop mid-job and wait on a second delivery.
Field notes
Past about 50 bags, stop bagging and order ready-mix — hand-mixing that volume risks cold joints between batches and eats a whole day. Order 5–10% over; you can't pause a pour to run for more, and a short load means a visible seam. Dampen the subgrade and set your forms dead level first, because concrete finds every low spot and won't forgive a sloppy base.
