Block Estimator
Block calculator
Masonry tools

Block Fill Calculator

Estimate grout or core-fill concrete for the hollow cells of a concrete block wall: every cell, or only the cells your plans call for.

Cells to fill

Grouting

Count from your plans, e.g. cells at each vertical bar and bond beam.

Size of one cell

Cell sizes differ between manufacturers and block types. Measure a block or use the manufacturer's figure.

Enter the cell as
in
in
in

Waste and price

%

0–30%. Applied once.

How the fill volume is calculated

  1. Count the cells to fill: every cell (blocks × cells per block) or only the cells your plans show.
  2. Work out one cell's volume: inside length × inside width × fill height.
  3. Multiply, then add your waste allowance once.

Example: 100 cells measuring 5 × 5 in inside, filled 8 in high, is 100 × 200 cu in = 11.57 ft³, or about 0.43 yd³ before waste.

Partly or fully grouted

Many block walls are only grouted where reinforcement is placed, such as at vertical bars and bond beams. Your plans decide which cells are filled; this calculator only works out the volume.

Frequently asked questions

Is core fill the same as mortar?

No. Mortar bonds the joints between blocks. Core fill is grout or concrete poured into the hollow cells. They are listed separately in the material list.

This estimates fill volume from the cell size and count you enter. It does not decide which cells must be grouted or reinforced. Follow your plans or engineer.