Mortar Calculator

The Mortar Calculator estimates how many bags of mortar you need to build a brick or concrete block wall — so you don't under-order and halt your project or over-buy and waste materials. Enter your wall length, wall height, block/brick type, and mortar joint thickness, then select your mortar bag size and waste factor to get the total bags of mortar needed. Secondary outputs include total blocks/bricks, mortar volume in cubic feet, and wall area.

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Add extra material for waste and spillage

Results

Bags of Mortar Needed

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Total Blocks/Bricks

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Mortar Volume

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Wall Area

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Frequently Asked Questions

How do I calculate how much mortar I need for a block wall?

Calculate mortar needs by determining wall area, block size, and joint thickness. Our calculator factors in the mortar volume needed for horizontal and vertical joints, plus waste allowance.

What's the yield of different mortar bag sizes?

A 40 lb bag yields about 0.3 cubic feet, 50 lb yields 0.375 cubic feet, 60 lb yields 0.45 cubic feet, and 80 lb yields 0.6 cubic feet of mortar when mixed.

How much waste factor should I add for mortar?

Add 10-15% waste factor for typical projects. For beginners or complex layouts, consider 15-20% to account for spillage, overfilling joints, and mixing losses.

What joint thickness should I use for concrete blocks?

Standard mortar joint thickness is 3/8 inch for concrete blocks and bricks. Thicker joints (1/2 inch) may be used for irregularly sized blocks or decorative purposes.

How many blocks fit in a square foot of wall?

For 8x8x16 inch blocks with 3/8 inch joints, you get approximately 1.125 blocks per square foot. For standard bricks (8x2x4), it's about 7 bricks per square foot.

Can I use this calculator for brick and block walls?

Yes, this calculator works for both concrete blocks and bricks. Select your specific block or brick size from the dropdown menu for accurate calculations.

What type of mortar should I use for different applications?

Type N mortar is most common for general construction. Type S offers higher strength for below-grade applications. Type M is for heavy loads and severe weather conditions.