CalcRover

QUIKRETE Calculator

Count bags of QUIKRETE concrete mix for a small pour: enter the dimensions, pick the bag size you can actually carry, and get the bag count with waste — computed from the manufacturer's published per-bag yields, rounded up like the pros do.

Bags from volume

Each bag size has a published yield — how much mixed concrete it makes: 40 lb ≈ 0.30 cu ft, 50 lb ≈ 0.375, 60 lb ≈ 0.45, 80 lb ≈ 0.60, 90 lb ≈ 0.675 (QUIKRETE's own spec; other brands like Sakrete are nearly identical). Divide your volume (plus waste) by the yield and round UP.

Rule of thumb from the yields: a cubic yard is 45 bags of 80 lb or 60 bags of 60 lb — at that point ready-mix delivery usually wins. QUIKRETE® is a registered trademark of the Quikrete Companies; this independent tool just uses their published specs.

bags = (volume × (1 + waste%)) ÷ bag yield, rounded up
yields: 40 lb → 0.30; 60 lb → 0.45; 80 lb → 0.60 cu ft

Worked examples

Example 1: 4 × 4 ft pad, 4 inches

How many 80 lb bags, with 10% waste?

  1. Volume.
    4 × 4 × 0.333 = 5.33 cu ft
  2. Waste, then divide by 0.60.
    5.87 ÷ 0.60 = 9.8 → 10 bags

10 bags of 80 lb (that's 800 lb of material — plan the trip accordingly).

Example 2: same pad with 60 lb bags

Lighter bags for easier carrying — how many?

  1. Divide the same 5.87 cu ft by the 60 lb yield.
    5.87 ÷ 0.45 = 13.0 → 14 bags
  2. Compare total weight.
    14 × 60 = 840 lb vs 10 × 80 = 800 lb

14 bags of 60 lb — a bit more material and more mixing batches, but each lift is 20 lb lighter.

Example 3: setting a fence post

A 10-inch hole, 2 ft deep, with a 4×4 post — bags of fast-setting mix?

  1. Hole volume minus the post.
    π × 0.417² × 2 − 0.3² × 2 ≈ 0.91 cu ft
  2. Divide by a 50 lb yield.
    0.91 ÷ 0.375 = 2.4 → 3 bags

About 3 bags of 50 lb per post — matching QUIKRETE's own fence-post guidance.

FAQ

How many 80 lb bags make a yard of concrete?+

45 bags (27 ÷ 0.60). With 60 lb bags it's 60, with 40 lb bags 90. Past roughly 20–25 bags, price and effort usually favor a ready-mix short load.

Do these numbers work for Sakrete or store-brand mix?+

Yes — standard concrete mixes yield almost identically per pound (the yield is set by physics, not branding). Check the bag's printed yield if in doubt; this tool uses QUIKRETE's published figures.

How much water per bag?+

Per QUIKRETE's instructions, about 3 quarts per 80 lb bag, scaled by size — but always follow the bag: too much water is the #1 cause of weak concrete.

Why round up instead of buying exact?+

You can't pour 9.8 bags, and running short mid-pour creates a weak cold joint. Unopened bags are returnable at the big-box stores — short slabs aren't.

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