Concrete Calculator

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Blocks for a 10×8 Wall

Count concrete blocks and mortar bags for a wall.

ft
ft
Total area to leave out.
ft²
16 in for standard block.
in
in
%

Your result

Enter your numbers and press the button. Your result appears here.

10 ft × 8 ft is 80 ft² of wall.

How it works

Blocks = wall area × 144 ÷ (block length × block height, with joints), plus extra. Mortar bags = blocks ÷ blocks per bag.

Example: a 10 ft wall 8 ft high is 80 ft², which takes 95 blocks with 5% extra and 8 bags of 80 lb mortar.

At a glance

Same settings as the calculator above, changing only the height.

HeightWall areaBlocksMortar bags
2 ft20 ft²242
4 ft40 ft²484
6 ft60 ft²716
8 ft80 ft²958

Standard block sizes

NominalActualBlocks per 100 ft² of wall
4×8×163⅝ × 7⅝ × 15⅝ in112.5
6×8×165⅝ × 7⅝ × 15⅝ in112.5
8×8×167⅝ × 7⅝ × 15⅝ in112.5
12×8×1611⅝ × 7⅝ × 15⅝ in112.5

Nominal sizes include a ⅜ in mortar joint.

Common questions

How many blocks per square foot?

A standard block with an 8×16 in face covers 1.125 blocks per square foot, or 112.5 blocks per 100 square feet.

How many blocks does a bag of mortar lay?

Quikrete lists its 80 lb Mortar Mix at up to 13 standard 8×8×16 blocks and its 60 lb bag at about 9.

Do I need rebar in a block wall?

Structural and retaining walls usually need vertical rebar and grout-filled cores. Follow your plans and local code.

Sources

  • Quikrete 80 lb Mortar Mix (blocks per bag), Lowe's listing: https://www.lowes.com/pd/QUIKRETE-80-lb-Gray-Type-Type-S-Mortar-Mix/5002094147