Mortar Calculator

Calculate how many bags of mortar or Type S masonry mortar you need for brick, block, or stone work. Get exact bag counts for walls, patios, and retaining walls based on area and joint size.

🧱 Masonry🏗️ Bags = Wall Area / Coverage per Bag
Wall or surface area (sq ft)
Mortar joint size (in)
Mortar type
Material being set
Please enter valid values.

Formula & Reference

VariableFormulaUnits
Mortar CalculatorBags = Wall Area / Coverage per Bagbags

Step-by-Step Examples

Example 1
Standard Brick Wall

160 sq ft brick wall, 3/8-inch joints, Type S.

  • Bags (60 lb) = 160/30 = 5.33 -> 6 bags
  • Or 80-lb bags: 160/35 = 4.57 -> 5 bags
  • Type S is the standard exterior mortar for most brick work
✓ 6 bags (60 lb) or 5 bags (80 lb)
Example 2
CMU Foundation

240 sq ft CMU wall, Type S.

  • 60-lb bags: 240/30 = 8 bags
  • 80-lb bags: 240/35 = 6.86 -> 7 bags
✓ 8 bags (60-lb) or 7 bags (80-lb)
Example 3
Natural Stone Wall

50 sq ft stone wall, wider joints (0.75 in).

  • Stone uses more mortar due to irregular shapes and wider joints
  • Estimate 50% more mortar than for brick: ~10 bags (60-lb)
  • Actual qty varies greatly by stone type and joint width
✓ Approx 10 bags (60-lb) for natural stone

Real-World Applications

Common Mistakes to Avoid

⚠️
Using the wrong mortar type

Type S (Portland + masonry cement) for exterior and below-grade work. Type N for interior. Type M for foundations and driveways. Never use interior mortar outdoors - it will fail.

⚠️
Not buying enough for repointing

Tuck-pointing existing joints requires more mortar than new work because you're grinding out and refilling existing joints. Add 25-50% extra for repointing projects.

⚠️
Mixing mortar too wet or too dry

Mortar consistency should resemble peanut butter - it should hold a thumbprint but not slump. Too wet = weak joints. Too dry = poor bonding.

Frequently Asked Questions

Which mortar type do I need?
Type S: exterior walls, below-grade, chimneys. Type N: interior walls and non-structural exterior. Type M: foundation walls, retaining walls. Refractory: fireplaces and high-temp applications.
How many sq ft does a bag of mortar cover?
A 60-lb bag covers approximately 25-30 sq ft of brick with 3/8-inch joints. An 80-lb bag covers 30-35 sq ft. Stone with wider joints uses significantly more mortar.
Can I mix mortar by hand?
Yes for small amounts up to about 50 lbs. Mix in a bucket with a margin trowel. For larger jobs, use a mortar mixer or rented paddle mixer. Machine mixing produces more consistent mortar.
How long does mortar take to cure?
Initial set: 1-4 hours. Full cure: 28 days. Keep new mortar work moist (mist with water) for the first 72 hours to prevent cracking from rapid drying. Protect from freezing for at least 24 hours.
What is the difference between mortar and grout?
Mortar is used to set and bond masonry units. Grout fills the joints between tiles after they are set. They have different compositions and should not be substituted for each other.

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