How much concrete do I need?
Multiply the area by the depth for a volume, then multiply the volume by 2400 kg per cubic metre for a weight. At 3.9 inches deep, 100 square feet of concrete is about 1.22 cubic yards, which weighs about 2.46 US tons. Enter your own measurements below.
Concrete calculator
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| Order by | Exact | Order, rounded up for anything sold in whole bags |
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Enter your measurements to see what to order.
How much concrete for a given area
At 3.9 inches deep, the depth Quikrete recommends.
| Area | Cubic yards | US tons | Cubic metres |
|---|---|---|---|
| 100 sq ft | 1.22 | 2.46 | 0.93 |
| 200 sq ft | 2.43 | 4.92 | 1.86 |
| 400 sq ft | 4.86 | 9.83 | 3.72 |
| 600 sq ft | 7.29 | 14.75 | 5.57 |
| 1,000 sq ft | 12.15 | 24.58 | 9.29 |
Every figure above is the calculator's own output at 2400 kg per cubic metre, with no waste added. Add 10 percent to any of them before ordering.
Why two suppliers deliver different weights for the same order
Published densities for concrete run from 2373 to 2500 kg per cubic metre. On a 4.86 cubic yard order that is the difference between 9.72 and 10.24 US tons. Normal weight concrete as placed, unreinforced. Four of the five independent sources land within 3 kg of 2,400, which is why the midpoint is the modal value rather than the arithmetic mean.
9 published figures from 8 suppliers, read 2026-09-20.
| Supplier | Published figure | Condition |
|---|---|---|
| Washington State Department of Transportation (WSDOT), Bridge Design Manual M 23-50.24, Chapter 5 Concrete Structures, Section 5.1.1.DUS | 0.150 kcf (= 150 lb/ft3) for normal-weight concrete; 0.155 kcf for prestressed concrete girders | Plain (unreinforced) concrete, hardened, in-place design value |
| Washington State Department of Transportation (WSDOT), Bridge Design Manual M 23-50.24, Chapter 3 Loads, Table 3.8-1 Permanent LoadsUS | 155 lb/ft3 for All Other Normal-Weight Reinforced Concrete including 5 lb/ft3 allowance for reinforcement; 165 lb/ft3 for precast pre-tensioned or post-tensioned spliced girders including 10 lb/ft3 allowance for reinforcement | Reinforced, hardened, in-place design value |
| Cemex USA (Ready Mix Concrete Calculator, FAQ block)US | about two tons (or 4,000 pounds) per cubic yard | Solid, unbroken (i.e. placed and hardened, not broken-out rubble) |
| Heidelberg Materials UK (Ready-mixed concrete pricing guide)UK | around 2.5 tons per cubic metre (= approx. 2,500 kg/m3) | Unstated (as supplied / as placed) |
| Holcim Australia (Glossary, Tools, FAQs and Resources)AU | around 2400 kg per cubic metre | Unstated (design value per AS 3600) |
| The Concrete Society (UK)UK | oven dry density between 2000-2600 kg/m3 | OVEN DRY |
| SMC Minimix (UK ready-mix supplier), Resource Centre FAQsUK | around 2.4 tonnes per cubic metre | Unstated (as delivered / as placed). |
| Wright Mix (UK on-site ready-mix and screed supplier), Concrete Calculator pageUK | an average of 2.4 tonnes per cubic metre | Unstated (average, as delivered) |
| Ohio University, 'Weights Of Building Materials, Agricultural Commodities, and Floor Loads For Buildings' (course handout H-20, hcia350)US | 150 pounds per cubic foot | Unstated (dead-load design value) |
How much extra to order
10 percent. Covers over-dig, spillage and a sub-base that is not perfectly level. Concrete cannot be topped up once it has started to go off, so running short is the expensive failure.
How many tons in a cubic yard of concrete?
About 2.02 US tons, and one ton is about 0.49 cubic yards.
The concrete calculator handles circles, L-shapes and triangles, and switches to cubic metres and bulk bags.