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Cinder Block Calculator

Grout volume

Cinder Block Fill Calculator

Estimate concrete or grout to fill block cores. Core fill starts on, with a fully grouted assumption you can change.

Calculator

1

Wall dimensions

Enter length and height. Add more sections for corners or extra walls.

ft
ft

No wall sections calculated yet

2

Block size

Nominal face size includes the mortar joint. Width is the wall thickness.

Face dimensions are the wall face (length × height). Width is how deep the block sits in the wall.

3

Doors & windows

Subtract doors and windows from the wall area for a more accurate block estimate.

No openings yet. Solid walls skip this step.

4

Waste allowance

Extra blocks for cuts, breakage, and layout. Actual waste varies by project — this is an estimate, not a requirement.

5

Mortar & core fill

Optional material estimates. Assumptions are listed with the results.

Mortar

in

Default assumes about 33 standard 8×8×16 in blocks per 80 lb bag with a 3/8 in face-shell joint.

Not every wall has grouted cores. This is a volume estimate only — it does not determine reinforcement or engineering requirements.

6

Cost estimate

Optional. Enter your local prices — this tool does not assume market rates.

Enter your wall dimensions to see your estimate.

The diagram updates as you type.

Your estimate will appear here

Add a wall length and height to calculate blocks, mortar, and optional cost.

Filling cinder block cores

Hollow blocks are not always grouted. Many walls fill only cells with reinforcement, bond beams, or lintels. Fully grouted walls fill every core. This calculator lets you pick none, bond-beam level, every other core, full grout, or a custom percentage. Placement methods for partial and fully grouted walls are covered in the CMHA guide to grouting concrete masonry walls (opens in a new tab).

What the volume means

The estimate uses about 0.30 cubic feet of grout per typical two-core 8 in block when 100% filled, scaled by block width. Results are shown in cubic feet, cubic yards, and cubic meters. It does not select grout strength, slump, or rebar.

Still need a block count?

Fill volume is based on the number of blocks in the wall (before extra waste units you may not lay). Enter the wall first so both the block takeoff and the grout volume stay in sync.

Looking for the full estimator with wall diagram and openings? Use the cinder block calculator.