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Mortar Calculator

Calculate mortar for brick and block walls

Mortar Needed

74 bags

Wall Area

160 sq ft

Volume

37.0 cu ft

Cost

$592

Units
Bags Needed

74

Volume

37.0 cu ft

Wall Area

160 sq ft

Est. Cost

$592

Material Breakdown

Wall Area160 sq ft
Bricks/Blocks1,120
Mortar Volume (net)33.6 cu ft
Total w/ Waste37.0 cu ft

Summary

Bags (80 lb)74
Bricks/Blocks1,120
Mortar TypeType N
Waste Factor10%
Estimated Cost$592

Example Calculations

1Standard Brick Wall (20 ft × 8 ft)

Inputs

Wall Length20 ft
Wall Height8 ft
Joint Thickness0.375 in (3/8")
Brick TypeStandard Brick
Mortar TypeType N
Waste Factor10%

Result

Bags Needed74 bags
Wall Area160 sq ft
Bricks Needed1,120
Mortar Volume33.6 cu ft
Estimated Cost$592

Wall area = 20 × 8 = 160 sq ft. Bricks = 160 × 7 = 1,120. Mortar = (1120/100) × 3.0 = 33.6 cu ft. With 10% waste = 36.96 cu ft. Bags = 36.96 / 0.5 = 74 bags. Cost = 74 × $8 = $592.

2CMU 8" Block Wall (40 ft × 8 ft)

Inputs

Wall Length40 ft
Wall Height8 ft
Joint Thickness0.375 in (3/8")
Brick TypeCMU 8" Block
Mortar TypeType S
Waste Factor10%

Result

Bags Needed40 bags
Wall Area320 sq ft
Blocks Needed360
Mortar Volume18.0 cu ft
Estimated Cost$320

Wall area = 40 × 8 = 320 sq ft. Blocks = 320 × 1.125 = 360. Mortar = (360/100) × 5.0 = 18.0 cu ft. With 10% waste = 19.8 cu ft. Bags = 19.8 / 0.5 = 40 bags. Cost = 40 × $8 = $320.

Frequently Asked Questions

Q

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

For standard bricks at 7 per sq ft with 3/8" joints, you need about 0.21 cu ft of mortar per sq ft of wall (3 cu ft per 100 bricks). An 80 lb bag covers about 0.5 cu ft.

  • 3/8" joints use ~0.21 cu ft mortar per sq ft of standard brick wall
  • 1/2" joints increase mortar usage by roughly 33%
  • One 80 lb bag yields approximately 0.5 cu ft of mixed mortar
  • CMU blocks need fewer units per sq ft but more mortar per unit
  • Always add 10–15% extra for waste, dropped mortar, and cleanup
Brick/Block TypeUnits per sq ftMortar per 100 UnitsBags per 100 sq ft
Standard Brick7.03.0 cu ft42 bags
Modular Brick6.752.8 cu ft38 bags
CMU 8" Block1.1255.0 cu ft11 bags
CMU 12" Block1.1256.0 cu ft14 bags
Q

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

Type N is general purpose for above-grade walls. Type S is high-strength for structural and below-grade use. Type M is the strongest, used for foundations and retaining walls. Type O is low-strength for interior non-load-bearing walls.

  • Type N is the most common for general-purpose above-grade brickwork
  • Type S is required by most codes for below-grade and structural walls
  • Type M is overkill for most residential projects—use only where specified
  • Type O should never be used outdoors or in load-bearing applications
  • Check local building codes—some jurisdictions mandate Type S minimum
Mortar TypeCompressive StrengthBest UseCost per Bag
Type O350 psiInterior non-load-bearing walls$6–$8
Type N750 psiAbove-grade exterior walls$7–$9
Type S1,800 psiBelow-grade, structural, retaining$8–$10
Type M2,500 psiFoundations, heavy loads$9–$12
Q

How many bags of mortar do I need for 1000 bricks?

For 1000 standard bricks with 3/8" joints, you need about 30 cu ft of mortar, which equals roughly 60 bags of 80 lb pre-mixed mortar. Add 10% for waste.

  • 1,000 standard bricks = ~30 cu ft mortar = 60 bags (80 lb)
  • With 10% waste factor: order 66 bags to be safe
  • Pre-mixed bags ($7–$10 each) are convenient for small walls
  • For walls over 500 bricks, buying sand and cement separately saves 30–40%
  • A skilled mason lays 400–500 bricks per day with mortar
Q

How thick should mortar joints be?

Standard mortar joints are 3/8" (9.5 mm) thick. Some applications use 1/2" joints for CMU blocks. Thicker joints require more mortar but can accommodate slight brick size variations.

  • 3/8" (9.5 mm) is the standard joint for most brick walls
  • 1/2" (12.7 mm) joints are common with CMU blocks and rough-cut stone
  • Thicker joints use ~33% more mortar than 3/8" joints
  • Consistent joint thickness is critical for wall strength and appearance
  • Use a jointing tool or dowel rod as a spacer for uniform joints
Q

How long does a bag of mortar last?

An 80 lb bag of pre-mixed mortar yields about 0.5 cu ft of mixed mortar. Once mixed, mortar remains workable for 90 minutes to 2 hours depending on temperature and humidity.

  • Mix only what you can use in 90 minutes—mortar stiffens quickly
  • Hot, dry weather cuts working time to 60–75 minutes
  • Cool, humid conditions extend working time to ~2 hours
  • Never re-temper (add water to) mortar that has begun to set
  • Store unmixed bags in a dry area—shelf life is 12 months unopened

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Last Updated: Mar 9, 2026

This calculator is provided for informational and educational purposes only. Results are estimates and should not be considered professional financial, medical, legal, or other advice. Always consult a qualified professional before making important decisions. UseCalcPro is not responsible for any actions taken based on calculator results.

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