Mortar Calculator

Estimate mortar bags, sand, and cement for brick or block walls — with cost breakdown by mortar type.

Wall Dimensions

Mortar Type

Joint Thickness

Unit Type

Cost per Bag ($)

Mortar Bags Needed (10% waste)

Type S (Structural / Below-Grade)

Wall area	160 sqft
Mortar bags	6 bags
Sand	0.15 tons
Cement bags (site-mix option)	3 bags

Mortar cost (@ $14.00/bag)	$84.00
Sand cost (@ $30/ton)	$4.50
Total materials	$88.50

info

Danny Reeves:Type S mortar is the default for structural and below-grade. Type N is fine for above-grade veneer but don’t use it on retaining walls — you’ll get called back.

Frequently Asked Questions

Type N vs Type S vs Type M — when to use each?

Type N (750 PSI) is the most common for above-grade, non-load-bearing walls and interior partitions. It has the best workability and is easiest to tool. Type S (1,800 PSI) is required for structural walls, below-grade foundations, retaining walls, and any exterior wall subject to wind or seismic loads. Most commercial specs default to Type S. Type M(2,500 PSI) has the highest compressive strength and is specified for below-grade masonry in contact with earth (basement walls, manholes, catch basins) and for engineered masonry requiring high axial load capacity. When in doubt, use Type S — it covers the widest range of applications.

How many bags of mortar per 1,000 bricks?

For modular brick with a 3/8-inch joint, plan on approximately 33–35 bags of pre-mixed mortar per 1,000 bricks (1 bag covers about 30 bricks). With a 1/2-inch joint, usage increases to roughly 40 bags per 1,000 bricks. These numbers assume single-wythe running bond. Flemish bond and other patterns with more head joints will use 10–15% more mortar. Always add 10% for waste, dropped mortar, and repointing.

Can I mix mortar types on the same project?

Yes, but only where the spec allows it and where different structural requirements apply to different parts of the wall. A common example: Type S for below-grade foundation walls transitioning to Type N for above-grade veneer on the same building. Never mix types within the same wall section or course — the different strengths and bond characteristics can cause cracking at the transition. Always document which type was used where for the project record.

How long does mortar stay workable?

Pre-mixed mortar stays workable for about 90 minutes to 2 hours after mixing, depending on temperature and humidity. In hot weather (above 90 degrees F), that window can shrink to 60 minutes. You can re-temper mortar once by adding a small amount of water and remixing, but only within the first 2.5 hours. After that, discard it — retempering past initial set weakens the bond. Mix smaller batches in hot weather to avoid waste.

Methodology: For brick walls, 1 bag of pre-mixed mortar covers approximately 30 sqft of wall with 3/8" joints or 25 sqft with 1/2" joints. For CMU block (8x16), 1 bag covers 12 blocks with 3/8" joints or 10 blocks with 1/2" joints. A 10% waste factor is applied to all quantities. Sand at 50 lbs per bag (0.025 tons). Site-mix cement bags estimated at 0.5 per mortar bag. Costs are material only and do not include labor. Prices reflect 2026 national averages.

How the Mortar Calculator works

You can enter wall area directly or give length and height and let the tool multiply them. From there the path splits depending on whether you are laying brick or CMU block, because coverage is quoted differently for each.

For brick, coverage is square feet of wall per bag: 30 square feet at a 3/8 inch joint, 25 at a 1/2 inch joint. Wall area is divided by that coverage and multiplied by 1.10 for waste, then rounded up to whole bags.

For block, coverage is quoted in blocks per bag, so the tool converts area to a block count first. An 8 by 16 inch block plus a 3/8 inch joint occupies (8 + 0.375) ÷ 12 by (16 + 0.375) ÷ 12, or 0.952 square feet. Blocks are then divided by 12 per bag at a 3/8 inch joint, or 10 per bag at 1/2 inch, with the same 10% waste allowance.

Sand is estimated at 0.025 tons per bag of mortar and priced at $30 per ton. Portland cement is estimated at half a bag per bag of mortar for crews batching on site. Worked example: 160 square feet of brick at a 3/8 inch joint is 160 ÷ 30 = 5.33 bags, and adding 10% gives 6 bags. That carries 0.15 tons of sand and 3 bags of cement. At $14 per bag of Type S the mortar is $84 and the sand $4.50, for about $88.50 in materials.

Frequently Asked Questions

How many bags of mortar do I need per square foot of brick wall?

At a 3/8 inch joint the calculator assumes one 80 lb bag covers 30 square feet of brick wall, so roughly one bag per 30 square feet before waste. At a 1/2 inch joint that drops to 25 square feet per bag, because the wider joint holds more mortar. A 10% allowance is added on top of either figure.

What is the difference between Type N, S, and M mortar?

Type N is the general-purpose mix for above-grade walls and is the softest of the three. Type S is stronger and is specified for below-grade work, foundations, and anything carrying lateral load. Type M is the highest strength and is used where heavy loads or severe exposure demand it. The calculator uses the type only to set a default bag price — $12 for N, $14 for S, $16 for M — since coverage per bag is similar across types.

How does the block calculation differ from brick?

For CMU the tool converts wall area into a block count first. An 8 by 16 inch block with a 3/8 inch joint occupies 8.375 by 16.375 inches, which is 0.952 square feet of wall face. It then applies coverage of 12 blocks per bag at a 3/8 inch joint, or 10 blocks per bag at 1/2 inch, and adds the same 10% waste.

Why does the tool list cement bags separately?

The cement line estimates half a bag of Portland cement per bag of mortar mix, for crews that site-batch rather than buy pre-blended bags. If you are ordering pre-blended Type N, S, or M in bags, you do not need the separate cement and can order sand only.