Mortar Calculator — Bag Quantities for Brick & Block Walls

Calculate 80 lb or 60 lb mortar bag quantities for brick and CMU block walls, with joint size adjustments, waste allowance, and cost comparison.

Last updated: October 16, 2026

Mortar Calculator
Unit type
Wall dimensions
sq ft
= 675 bricks at 6.75/sq ft
in
in
Waste allowance
%
Edit local pricing
$
$
Recommended buy
62 80 lb bags
$372.00 total · 675 bricks
Bricks
675
From 100 sq ft wall area
Best Value
$372.00
62 bags

Compare bag sizes

Mortar for 675 bricks with 10% waste.

Purchase OptionQuantityEst. Cost
80 lb BagsBest value62 bags$372.00
60 lb Bags83 bags$415.00
Best value: 80 lb Bags at $372.0080 lb bags are more cost-effective per pound of mortar. Heavier to handle but the best material value.
Consider buying by the palletFor large jobs requiring 30+ bags, most suppliers offer pallet pricing (35–42 bags per pallet) at a significant discount.
This is an estimate based on standard mortar joint sizes and typical coverage rates. Actual mortar usage varies with joint profile, tooling, mix consistency, and mason technique. Always buy extra to avoid running short mid-job.

Tools and Materials for Masonry Work

Organize tools, materials, and safety gear before laying the first course to maintain workflow and prevent mortar stiffening on the board.

  • Essential Tools: London or Philadelphia pattern masonry trowel, margin trowel, concave jointer or tuck pointer, mortar board (hawk or plywood sheet), 5-gallon buckets, mortar mixer or heavy-duty mixing tub, hoe with cutouts, line pins and mason line, and a 4-foot spirit level.
  • Core Materials: Pre-mixed mortar bags (Type N or Type S), clean potable water, masonry ties or wall anchors, and brick or concrete masonry units (CMU).
  • Safety Equipment: N95 dust mask or respirator (silica dust protection during dry mixing), heavy-duty rubber work gloves (alkaline mortar protection), safety glasses with side shields, and thick knee pads.
  • Nice-to-Have Additions: Masonry sponge, plastic sheeting (to keep work moist or protect against sudden rain), mortar color pigments, and an acid-free masonry cleaner for final washdown.

Mortar Mix Types & Coverage Reference

Selection depends on above-grade, below-grade, or restoration use. Coverage rates assume standard 3/8-inch bed and head joints.

Mortar mix classifications, compressive strengths, and practical bag yields.
Mortar TypeCompressive StrengthPrimary Application80 lb Bag YieldApprox. Coverage
Type N (80 lb)750 psiExterior above-grade walls, brick veneer, chimneys0.67 cu ft130–140 standard bricks
Type N (60 lb)750 psiSmall repairs, short garden walls, brick veneer0.50 cu ft95–105 standard bricks
Type S (80 lb)1,800 psiBelow-grade foundation walls, CMU blocks, retaining walls0.67 cu ft30–34 standard 8x8x16 CMUs
Type S (60 lb)1,800 psiLight concrete block work, structural repairs0.50 cu ft22–25 standard 8x8x16 CMUs
Type M (80 lb)2,500 psiHeavy load-bearing walls, stone masonry, footings0.67 cu ft120–130 standard bricks
Type O (80 lb)350 psiHistoric restoration, soft natural stone, interior veneer0.67 cu ft130–140 standard bricks

Common Mortar Estimation Mistakes

Ignoring waste and droppage. Mortar falls off boards, extrudes during striking, and hardens in the pan. Without a 10–15% waste allowance, you'll run short before the top course.

Not adjusting for joint size. Standard estimates assume 3/8-inch joints. Widening to 1/2 inch increases mortar volume by over 30%.

Using concrete mix instead of mortar. Concrete mix contains coarse aggregate for pours; mortar uses fine sand, cement, and lime for thin joints. For structural footings, use a concrete bag calculator.

Overestimating block bedding. CMUs use face-shell bedding (mortar on outer edges only), not full-bed coverage. Assuming full bed doubles your order.

Neglecting brick absorption. High-suction clay bricks pull moisture from fresh mortar. Wet porous units before laying or adjust batch sizing to prevent premature stiffening.

Mortar Quantity Formulas

Standard modular bricks require ~6.75 per sq ft at 3/8-inch joints. CMU blocks (8x8x16 nominal) require 1.125 per sq ft.

Formulas

  • Brick Count = Wall Area (sq ft) × 6.75 × (1 + Waste Factor)
  • 80 lb Mortar Bags (Brick) = Total Brick Count ÷ 135
  • CMU Block Count = Wall Area (sq ft) × 1.125 × (1 + Waste Factor)
  • 80 lb Mortar Bags (CMU) = Total CMU Block Count ÷ 32
  • 60 lb Mortar Bags = 80 lb Bag Requirement ÷ 0.75

Worked Example

A 12 ft × 10 ft brick veneer wall (120 sq ft), Type N mortar, 10% waste:

  • Bricks: 120 sq ft × 6.75 = 810 → × 1.10 = 891 bricks. Confirm with our brick calculator.
  • 80 lb bags: 891 ÷ 135 = 6.6 → 7 bags.
  • 60 lb bags: 6.6 ÷ 0.75 = 8.8 → 9 bags.

With 8x8x16 CMU blocks instead: 120 sq ft × 1.125 × 1.10 = 149 blocks ÷ 32 = 4.65 → 5 bags of 80 lb Type S. Use our concrete block calculator for larger foundations.

Pre-Mixed Bags vs. Site-Mixed Mortar

Pre-Mixed Bags: Factory-proportioned cement, lime, and sand — just add water. Eliminates proportioning errors, ensures color consistency, and suits DIY and small-to-medium jobs. Higher per-cubic-foot cost vs. bulk sand.

Site-Mixed (1:1:6 ratio): Portland cement + hydrated lime + masonry sand. Drastically lower unit cost on large projects (thousands of bricks), but demands consistent on-site measuring, sand moisture management, and more labor.

  • Pro Tip: Under 20–25 bags (~2,500 bricks or 600 blocks), use pre-mixed 80 lb bags. Consistency and saved setup time outweigh the price premium.

Frequently Asked Questions

How many standard bricks can I lay with one 80 lb bag of mortar mix?

One 80 lb bag of standard pre-mixed mortar (Type N or Type S) yields about 0.67 cubic feet of wet mortar, which is enough to lay roughly 130 to 140 standard modular bricks with standard 3/8-inch bed and head joints.

How many concrete blocks (CMU) can one bag of mortar cover?

An 80 lb bag of mortar mix will lay approximately 30 to 34 standard 8x8x16 concrete masonry units (CMUs) using face-shell bedding and 3/8-inch mortar joints. A 60 lb bag covers roughly 22 to 25 blocks.

What is the primary difference between Type N and Type S mortar mix?

Type N mortar offers moderate compressive strength (around 750 psi) and high workability, making it ideal for above-grade exterior walls, chimneys, and brick veneers. Type S provides higher compressive strength (1,800 psi) and stronger lateral bond strength, making it mandatory for below-grade foundation walls, retaining walls, and structural CMU block work.

How much water do I add to an 80 lb bag of pre-mixed mortar?

Most standard 80 lb bags of mortar require approximately 4 to 5 quarts (1.0 to 1.25 gallons) of clean water. Add water gradually while mixing until you achieve a smooth, buttery consistency that holds its shape on a trowel without slumping.

How does increasing mortar joint thickness affect bag quantities?

Increasing joint thickness from the standard 3/8-inch to 1/2-inch increases mortar volume requirements by roughly 30% to 35%. If your project uses 1/2-inch joints, multiply your baseline calculated bag requirement by 1.33.

How long does mixed mortar remain usable on the mortar board?

Under standard outdoor temperatures (around 70°F), mixed mortar remains usable for 1.5 to 2 hours. In hot, windy conditions, mortar loses moisture rapidly and may dry out in 30 to 45 minutes. You can retemper mortar by adding a small amount of water during the first 1.5 hours, but discard any mortar older than 2 hours as cement hydration begins.