Mortar Calculator
Estimate mortar bags, sand, and water for masonry work
Total wall surface area to be mortared
Standard masonry joint: 0.375" (3/8")
Select the brick type for accurate yield
Mortar Bags
—
80 lb bags
Sand
—
cu yd
Water
—
gal
Mortar Volume
—
cu ft
Disclaimer: Results are estimates based on standard formulas. Not a substitute for professional advice from a licensed contractor, engineer, or architect. Verify all calculations before making purchasing or construction decisions.
How to Use This Calculator
Mixing the right amount of mortar keeps your masonry project moving without waste. Our calculator estimates mortar bags, sand, and water based on wall area and joint thickness.
- Enter the total wall area in square feet
- Set the mortar joint thickness (3/8" is standard)
- Choose your brick size for accurate yield
- Review the mortar bags, sand, and water estimates
Expert Insights
Smart analysis for your Mortar project
Bag Yield Intelligence
An 80 lb bag of premixed mortar yields about 0.7 cubic feet. Our calculator converts your joint volume into accurate bag counts.
Mortar Type Selection
Type N suits above-grade walls; Type S handles load-bearing and below-grade. Always match mortar type to the structural requirement.
Mix Consistency
Too much water weakens mortar. Add roughly 1.25 gallons per 80 lb bag and adjust slowly until the mix holds a slump similar to peanut butter.
Calculation Formula
Mortar volume (cu ft) = Wall area x Joint thickness / 12
Mortar bags (80 lb) = ceil(Mortar volume x 1.4)
Sand (cu yd) = (Mortar volume x 3.5) / 27
Water (gal) = Mortar bags x 1.25
Mortar Type Comparison
| Mortar Type | Compressive Strength | Best Use | Cement:Lime:Sand |
|---|---|---|---|
| Type M | 2,500 psi | High-load, below grade | 1:0.25:3 |
| Type S | 1,800 psi | Load-bearing, below grade | 1:0.5:4.5 |
| Type N | 750 psi | Above-grade walls | 1:1:6 |
| Type O | 350 psi | Interior, non-load-bearing | 1:2:9 |
Authority References
Our calculations are based on guidelines and standards from these authoritative sources:
- National Concrete Masonry Association (NCMA) — Mortar TEK Notes. Learn more
- American Society for Testing and Materials (ASTM) — ASTM C270: Standard Specification for Mortar. Learn more
- Portland Cement Association (PCA) — Mortar & Masonry Guides. Learn more
Frequently Asked Questions
How much mortar do I need per square foot?
For a standard 3/8" mortar joint, expect about 0.044 cubic feet of mortar per square foot of wall, or roughly one 80 lb bag per 22-23 sq ft of wall area.
What is the difference between Type N and Type S mortar?
Type N is a general-purpose mortar for above-grade walls with moderate strength (750 psi). Type S has higher strength (1,800 psi) and is used for load-bearing and below-grade applications.
How much water do I add to a bag of mortar?
An 80 lb bag of premixed mortar requires about 1.25 gallons (5 quarts) of clean water. Add water gradually until the mix reaches a workable, buttery consistency.