Guide
Concrete Bag Yield: 60lb vs 80lb vs 90lb Bags
Published July 19, 2026
The real cubic-foot yield per bag differs enough between 60lb, 80lb, and 90lb concrete mix bags that using a flat 'half a cubic foot per bag' rule of thumb across all three sizes will consistently miscalculate an order, sometimes by a meaningful number of bags on a larger pour — the yield figures below are what the concrete slab, post, and steps calculators on this site actually use.
Yield by bag size
- 60lb bag: yields approximately 0.45 cubic feet of mixed concrete — the lightest and most common bag size for smaller DIY jobs, easiest to carry and mix by hand.
- 80lb bag: yields approximately 0.6 cubic feet — a common step up for slightly larger jobs, offering more yield per bag but noticeably heavier to handle.
- 90lb bag: yields approximately 0.675 cubic feet — less commonly stocked than 60lb/80lb but offers the most yield per bag among the standard sizes, at the highest per-bag weight.
These figures vary slightly by manufacturer and specific product formulation (some mixes include additives that change density slightly), so checking the exact bag's printed yield is worth doing for a large or critical pour.
Bag count vs. ready-mix truck: the crossover point
Mixing concrete by the bag is labor-intensive — a single cubic yard requires roughly 60 sixty-pound bags or 45 eighty-pound bags, each needing individual mixing (by hand or in a small mixer) and placement before the batch starts setting. Somewhere around 1 to 1.5 cubic yards, most people find the labor of mixing and placing that many bags exceeds the cost and coordination of ordering ready-mix delivery, which arrives as one continuous, professionally mixed batch.
Ready-mix trucks usually have delivery minimums (commonly around 1 cubic yard or more) and short-load fees below that minimum, so very small pours (a single post hole, a small step) are still typically more practical by bag even though bags cost more per cubic foot of concrete than bulk ready-mix.
Sizing your bag order
The concrete slab calculator, concrete post calculator, and concrete steps calculator each convert your project's volume to bag count using these real per-bag yield figures, always rounding up to whole bags — see concrete bags vs ready-mix for the fuller decision framework beyond just the crossover point.
Reading a bag's mix design
Beyond weight and yield, bags are also formulated for different applications — a standard general-purpose mix, a high-early-strength mix for faster cure, and a fiber-reinforced mix for extra crack resistance are all sold in similar bag sizes but aren't interchangeable for every job. Checking the specific product's intended use (general purpose, fence post, countertop, etc.) alongside its yield figure avoids using the wrong formulation for a job that has particular strength or cure-time requirements.
Aggregate size and its effect on yield
Standard concrete mix contains coarse aggregate (gravel) alongside sand and cement; some specialty mixes (like a sand-mix or a countertop-specific mix) use finer or no coarse aggregate at all, which changes both the yield-per-bag figure and the finished product's strength and appearance — a sand mix without coarse aggregate typically isn't structurally appropriate for a load-bearing footing or slab, so checking that the aggregate composition matches your application is worth doing alongside the basic yield-per-bag check.
Storage and shelf life of unused bags
Unopened bags stored dry and off the ground can typically be kept for many months to a year or more without significant strength loss, but bags exposed to moisture (even ambient humidity through a torn or improperly sealed bag) can begin to partially cure inside the bag, reducing usable yield and final strength — a bag that feels lumpy or has visible hardened clumps through the packaging should be considered compromised rather than used for a critical structural pour.
FAQ
How many 80lb bags make a cubic yard?
Roughly 45 bags, based on the approximate 0.6 cubic foot yield per bag and 27 cubic feet per cubic yard — a useful rough figure for estimating labor and delivery logistics on a bag-mixed job of that size.
Is a 90lb bag always the better value?
Not necessarily — it yields more concrete per bag but is also considerably heavier to lift and mix by hand, so for a solo DIY job, 60lb or 80lb bags are often more practical even at a slightly lower yield-per-bag efficiency.
Do all bag brands yield the same amount at the same weight?
Not exactly — while 60lb, 80lb, and 90lb are the common weight classes across most brands, exact cubic-foot yield can vary slightly by manufacturer and specific formulation (additives, aggregate size), so always check the yield figure printed on your specific bag rather than assuming it matches another brand's bag of the same weight.
Is fast-setting concrete mix measured the same way as standard mix?
Yield is generally similar by weight class, but fast-setting mixes have a much shorter working time before they begin to set, which changes the practical mixing and placement logistics (smaller batches, faster work) even though the underlying bag-to-cubic-foot yield math doesn't change.
How can I tell if a stored bag of concrete mix has gone bad?
Check for hardened lumps or clumps through the packaging, or a bag that feels unusually heavy or damp for its size — any of these signs suggest moisture has partially cured the mix inside the bag, which reduces both usable yield and final strength, and such a bag shouldn't be relied on for a structural pour even if it still technically pours out.
Should I buy a few extra bags beyond the calculated total for a pour?
A small cushion (one or two extra bags) is reasonable insurance against an uneven subgrade or minor form spillage beyond what the standard 5-10% waste allowance already covers, particularly on a pour where running short mid-placement would be especially disruptive to stop and restart.
Do different brands' bag yield figures ever differ enough to change a bag-count decision?
Occasionally, especially between a standard mix and a specialty high-yield formulation, so it's worth comparing the actual printed yield rather than assuming all 80lb bags on a store shelf are interchangeable for a large or cost-sensitive order.
Does adding rebar or wire mesh change the bag-yield calculation?
No — reinforcement occupies negligible volume relative to the total pour, so it doesn't meaningfully change the concrete volume or bag count needed, though the reinforcement itself is a separate line item priced and ordered by length or area rather than folded into the concrete calculation.