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EstimatorKit

Concrete, gravel, sand, mulch and soil

Work out how much material you need — in bags, yards and tons

An area and a depth are all it takes to reach the quantity a supplier can act on: cubic yards, whole bags, tons on the scale ticket. Measurements go in the way they came off the tape, fractions and all, and the two numbers that quietly ruin orders are shown instead of hidden — the waste you are allowing for, and the extra depth that loose material needs because it compacts. Add what your yard charges per bag and per cubic yard and it also answers the real question, which is whether to carry bags home or pay for a delivery.

  • Feet, inches and fractions
  • Bags, yards and tons
  • Your prices, not ours
Material

4 in is the usual slab for a patio, shed or walkway.

Shape

Feet unless you say otherwise. 12' 6 3/8", 150 in and 3.8 m all read correctly.

Add your prices to compare bags against bulk

We do not ship a price list — it would be wrong in half the country the day it shipped. These are yours.

Order this much concrete

3.11 cu yd

80 lb bags
140
Area
240 sq ft
Cubic feet
84

Bags or bulk

At 3.11 yd³ this is usually past the point where bags pay — that is 140 bags to carry and mix. Enter your own prices to compare properly.

All 19 calculators

Area and volume, lumber and framing, interior finishes, the yard and the water, and two fastener charts — every one of them runs in this tab and answers in units a supplier sells.

Bags, yards and the extra you order

How many bags of concrete are in a cubic yard?

Forty-five 80 lb bags, sixty 60 lb bags or ninety 40 lb bags. A cubic yard is 27 cubic feet and an 80 lb bag yields 0.6 of a cubic foot — the yield printed on the bag — so the arithmetic is 27 ÷ 0.6. That number is also the reason the site flags roughly a yard as the point where bags stop making sense: forty-five bags is 3,600 lb to lift twice before any of it is mixed, and around there a short-load fee usually costs less — a rule of thumb, not a specification.

Why does the calculator order more material than my measurements say?

Two separate allowances, and both are shown rather than folded in. The waste allowance covers cuts and spillage and you set it. The compaction or settling allowance applies only to materials that lose depth after they are placed — gravel and crushed stone under a plate compactor, topsoil and compost after watering in. Set the waste to zero if you want the bare geometry; the compaction figure is per material and is explained on the page that uses it.

Area, then depth, then what the supplier sells

Every material estimate is the same three-step calculation wearing different clothes: work out an area, multiply it by a depth to get a volume, then convert that volume into whatever the supplier actually sells. The last step is the one that matters and the one most calculators skip. Nobody buys 1.48 cubic yards of concrete. They buy sixty-seven 80 lb bags, or they buy two yards from a truck and accept that half a yard goes into a form they will build for the purpose. A page that stops at the volume has handed you an intermediate result and called it an answer.

Two adjustments sit between the geometry and the order, and they pull in opposite directions. Waste is material you buy and do not place — offcuts, spillage, the tile that cracks. Compaction and settling are the reverse: material you place and then lose, because loose aggregate gives up depth under a plate compactor and screened topsoil settles once it is watered in — this site allows a fifth for the first and 15% for the second, working allowances rather than measured ones. Ignore the first and you make a second trip; ignore the second and the finished job is thinner than it was meant to be. Both are visible wherever a page uses them, with the bare figure next to the adjusted one, because a calculator that silently pads its own answer is not one you can check against a quote.

The unit conversions themselves are worth having open in their own right — the cubic yard calculator for turning an area and a depth into a delivery, and the square footage calculator for the rooms and lots that are never a plain rectangle. The materials themselves are all on this page: concrete by the 80 lb bag, gravel, crushed stone and sand by the ton, mulch at a depth that is horticultural rather than structural, and topsoil and compost with the settling they lose to the first rain — which the topsoil calculator takes as far as the truckload.