Concrete Yield Calculator

1. Enter the batch weights: cement, water, sand, gravel and any admixtures, in pounds.
2. Enter the measured density (unit weight) from the ASTM C138 test, in pounds per cubic foot.
3. Optionally enter the designed yield to get the relative yield, the key quality-control number.
4. Read the yield in cubic yards and feet, the relative yield, and the cement content.

Here is what each result means:

Concrete yield is the volume of concrete a batch actually produces from known quantities of materials. It is measured by the ASTM C138 gravimetric method: weigh the fresh concrete in a container of known volume to get the density, then work the yield back from the total batch weight.

It matters because yield tells you whether a batch delivered the volume it was supposed to. A short yield means a truck runs out before the pour is finished; an over-yield can signal a lean or under-dense mix. Batch plants, inspectors and concrete students use it as a basic quality-control check, alongside the air content the same test provides.

Yield is the total weight of all the materials divided by the fresh density, which gives the volume. Dividing by 27 converts cubic feet to cubic yards. The relative yield then compares that to the design.

1. Add the weights of cement, water, sand, gravel and admixtures for the total batch weight.
2. Divide by the measured density for the yield in cubic feet, and by 27 more for cubic yards.
3. Divide the yield by the designed yield for the relative yield.
4. Divide the cement weight by the yield for the cement content per cubic yard.

Suppose a batch has 600 lb cement, 300 lb water, 1,350 lb sand and 1,800 lb gravel, with a measured density of 150 pounds per cubic foot and a designed yield of 1.00 cubic yard.

Calculation: total weight = 4,050 lb. Yield = 4,050 / (150 x 27) = 1.00 cu yd, so the relative yield is 1.00 and the batch is on target. Cement content = 600 / 1.00 = 600 lb per cu yd.

If the density had measured 156 instead, the yield would fall to about 0.96 cubic yards, a short yield that would leave a pour short and point to a batching or air-content problem.

The relative yield is the number to watch. It compares the volume the batch made to the volume it was designed to make, and each direction tells you something.

A short yield is the one that bites: the truck runs out before the pour is done. An over-yield wastes a little material but can hint that the concrete is lighter, and lower strength, than intended.

Measured Density

Yield is weight divided by density, so an inaccurate density throws off the result. The density must come from a properly filled, consolidated and struck-off measure.

Air Content

More entrained or entrapped air lowers the density and raises the yield. The same ASTM C138 test gives the air content, which is why yield and air are read together.

Batch Weights

A wrong weight on any material changes the total and the yield. Use the actual batched weights, not the design weights, for a real check.

Moisture in Aggregate

Free water on sand and gravel adds to the water and the weight. Batch plants correct for it; if you do not, the yield and water-cement ratio drift.

Batch-plant Quality Control

Confirm each mix produces the designed volume and cement content before it ships in quantity.

Checking a Delivery

If a pour ran short, a yield check shows whether the batch made less than ordered.

Learning and Training

The ASTM C138 calculation is a standard exercise for concrete students and technicians; this tool does the arithmetic so you can focus on the method.

1. Using Design Weights, Not Batched Weights

A yield check compares what was actually batched. Using the design weights just returns the design.

2. a Poor Density Measurement

An under-filled or under-consolidated measure gives a low density and a false high yield. Follow the test method.

3. Forgetting Admixtures and Water on Aggregate

Leaving out admixtures or the free moisture on aggregate understates the total weight.

4. Mixing Up Yield and Relative Yield

Yield is a volume; relative yield is a ratio to the design. Report the right one.

5. Treating It as an Acceptance Test

This is the arithmetic. Acceptance needs the full ASTM C138 procedure with calibrated equipment.

The arithmetic is exact for the weights and density you enter; the result is only as good as the measured density and the batch weights.

Divide the total weight of all the batch materials by the measured fresh density to get the yield in cubic feet, then divide by 27 for cubic yards. For example, 4,050 pounds at 150 pounds per cubic foot is 1.00 cubic yard.

Relative yield is the actual yield divided by the designed yield. A value of 1.00 means the batch made exactly the designed volume; below about 0.98 is a short yield and above 1.02 is an over-yield.

ASTM C138 is the standard test method for the density, yield and air content of fresh concrete, measured by weighing a container of known volume. This calculator does its yield arithmetic; the full test needs calibrated equipment.

A short yield usually comes from a higher density than designed, often from low air content or a batching error. The batch makes less volume than ordered, so a pour can run short.

An over-yield comes from a lower density than designed, often from high air content or a lean mix. The batch makes more volume, which wastes a little material and can mean lower strength.

Divide the cement weight in the batch by the yield in cubic yards. If a batch with 600 pounds of cement yields 1.00 cubic yard, the cement content is 600 pounds per cubic yard.

Normal-weight concrete is about 140 to 150 pounds per cubic foot fresh. Lightweight mixes are lower. Use the density you actually measured, not a book value, for a real yield.

Air lowers the density, which raises the yield. Because the same ASTM C138 test gives density, yield and air content, a yield that is off often shows up as an air-content problem.

No. The calculation runs entirely in your browser and nothing you enter is stored or sent anywhere.

• National Ready Mixed Concrete Association (NRMCA; density, yield and air content testing).
• American Cement Association (Portland Cement Association) (American Cement Association; fresh concrete properties).
• QUIKRETE Concrete Mix product data (QUIKRETE; yield and coverage).
• QUIKRETE concrete and bag calculator (QUIKRETE; volume and yield method).