Mortar Calculator: Free Online Masonry Mortar Estimator
Use our free mortar calculator to determine exactly how much mortar mix you need for bricklaying, block work, stone masonry, and tile setting. Designed for masons, bricklayers, and DIY homeowners, this tool calculates mortar volume in cubic feet, the number of mortar mix bags required, and the individual quantities of cement, lime, and sand based on your wall area and mortar type. Enter your brick or block count and joint dimensions to get precise, ready-to-use batch quantities instantly.
How to use this calculator.
- Determine your masonry area or brick count. For a wall, calculate the total square footage (length times height). Alternatively, count the number of standard bricks or CMU blocks you will lay.
- Select your mortar type. Choose from Type N (general-purpose, 750 psi), Type S (structural, 1,800 psi), Type M (heavy-duty, 2,500 psi), or Type O (restoration/repointing, 350 psi) based on your project requirements.
- Enter your joint thickness. Standard brick joints are 3/8 inch. Block joints are typically 3/8 to 1/2 inch. Wider joints consume significantly more mortar.
- Review your mortar quantities. The calculator displays total mortar needed, the number of pre-mixed mortar bags, or the individual cement, lime, and sand quantities if mixing from scratch.
How do you calculate mortar quantities for masonry work?
Mortar quantity is calculated based on the number of masonry units, their dimensions, the joint thickness, and the mortar type selected.
Mortar Volume (cu ft) = Number of Bricks × Joint Volume Per Brick
Pre-Mixed Bags = Total Mortar Volume ÷ Bag Yield
Sand (cu ft) = Mortar Volume × Sand Ratio
Where:
- Standard modular brick size: 7-5/8" × 2-1/4" × 3-5/8" (nominal 8" × 2-2/3" × 4"). One modular brick with 3/8" joints requires approximately 0.023 cubic feet of mortar.
- Type N mortar ratio: 1 part Portland cement : 1 part hydrated lime : 4.5-6 parts sand by volume.
- Type S mortar ratio: 2 parts Portland cement : 1 part hydrated lime : 6-9 parts sand by volume.
- Pre-mixed mortar bag yield: A 60-lb bag yields approximately 0.45 cubic feet. An 80-lb bag yields approximately 0.60 cubic feet.
- Sack of masonry cement: A 70-lb sack of Type N masonry cement yields approximately 2.5-3.0 cubic feet of mortar when mixed with sand.
Example calculation.
Let's calculate the mortar needed for a brick garden wall.
Scenario: You are building a brick wall 20 feet long and 4 feet high (80 square feet) using standard modular bricks with 3/8-inch joints and Type N mortar.
- Calculate number of bricks: Standard modular bricks lay approximately 7 bricks per square foot. 80 sq ft × 7 = 560 bricks.
- Calculate mortar volume per brick: For modular brick with 3/8" joints, approximately 0.023 cubic feet of mortar per brick.
- Total mortar volume: 560 bricks × 0.023 cu ft = 12.88 cubic feet of mortar
- Calculate pre-mixed bags: 12.88 ÷ 0.60 (80-lb bag yield) = 21.5 bags. Round up to 22 eighty-pound bags of Type N mortar mix.
- Mixing from scratch (cement + lime + sand): For 12.88 cu ft at 1:1:5 ratio: approximately 2.15 cu ft of Portland cement (about 2.5 bags), 2.15 cu ft of hydrated lime, and 10.75 cu ft of masonry sand.
Result: For an 80-square-foot brick wall, you need approximately 22 eighty-pound bags of Type N mortar mix. If mixing from scratch, approximately 2.5 bags of Portland cement, 2.5 bags of hydrated lime, and 0.5 cubic yards of masonry sand. Your mortar should be workable and sticky, not crumbly or runny.
Tips from the field.
- Match your mortar to your brick strength. Mortar should be weaker than the masonry unit it bonds. If mortar is stronger than the brick, thermal movement and settlement will crack the brick rather than the mortar joint. Cracked bricks cannot be repaired; cracked mortar joints can be repointed.
- Retemper mortar within the first 2 hours. Mortar that has stiffened but not set can be retempered by adding a small amount of water and re-mixing. After 2-2.5 hours, discard mortar that has begun its initial set: adding water after initial set produces mortar with near-zero bond strength.
- Wet your bricks before laying in hot weather. Dry bricks suck water from the mortar too quickly, preventing proper hydration and bond. Briefly dip bricks in water or spray them down before laying in temperatures above 80°F. The brick surface should be damp but not standing wet.
- Use mortar boards, not the ground. Dumping mortar on the ground contaminates it with soil, organics, and debris that weaken the mortar. A mortar board or mixing tub keeps the mortar clean and workable. In cold weather, a heated mortar board prevents freezing.
- Color consistency requires precise batching. If your project uses colored mortar, batch all dry ingredients for the entire project at once or measure pigment by weight for each batch. Even slight variations in pigment quantity produce visibly different joint colors.
Disclaimer: This calculator provides estimates for planning purposes only. Actual mortar requirements vary based on brick size, joint thickness, mason technique, and waste. For structural masonry or load-bearing walls, consult a licensed structural engineer and follow local building codes. PavementCalculator.com assumes no liability for material overages, shortages, or mortar that fails to meet design specifications.
Cost, price, and density figures on this page reflect approximate U.S. averages as of August 2026 and vary by region, supplier, and material availability.
Frequently asked questions.
How much mortar do I need per brick?
For standard modular bricks (7-5/8 × 2-1/4 × 3-5/8 inches) with 3/8-inch mortar joints, you need approximately 6.5-7.5 cubic feet of mortar per 1,000 bricks. Per brick: approximately 0.007 cubic feet. An 80-lb bag of pre-mixed mortar yields about 0.65-0.7 cubic feet and lays approximately 90-110 standard bricks. Use our calculator above for your specific project dimensions and brick size.
What is the standard mortar mix ratio?
Type N mortar (general purpose, above grade): 1 part Portland cement, 1 part hydrated lime, 6 parts sand. Type S mortar (structural, below grade): 1:0.5:3.5-4.5. Type M mortar (high strength, foundations): 1:0.25:2.5-3. Type O mortar (low strength, interior, historic): 1:2:9. For simplicity, pre-mixed mortar bags are available: just add water. Masonry cement (Type N, S, or M) includes the lime already: mix with sand only, typically 1:2.25-3 (masonry cement:sand).
How many bags of mortar per square foot of block wall?
For standard 8×8×16 inch concrete blocks (CMU) with 3/8-inch joints: approximately 0.034 cubic feet of mortar per block face (bed joints + head joints). An 80-lb bag of mortar (0.7 cu ft) lays approximately 20-22 standard CMU blocks. For a 100 sq ft wall (approximately 113 blocks at 1.125 blocks/sq ft): you need about 5-6 bags of 80-lb mortar. This does not include grouting of cells, which is additional material.
What's the difference between mortar, grout, and thinset?
Mortar (masonry cement + sand + lime) is used to bond bricks, blocks, and stone together: it's structural, fills joints, and must support weight. Grout (cement + water, sometimes fine sand) is a fluid material used to fill cavities in block walls (for rebar) or fill gaps in tile: it's not a bonding agent. Thinset (modified Portland cement + fine sand + polymers) is an adhesive used to bond tile to substrates: it's applied in thin layers with a notched trowel.
How long does mortar take to cure?
Mortar achieves initial set in 2-4 hours (can support light loads). It reaches approximately 60-70% of design strength in 7 days and full design strength in 28 days when cured at 70°F. Hot, dry, or windy weather accelerates water evaporation and weakens mortar: cover fresh work with plastic and mist with water for 3-7 days (moist curing). In cold weather (below 40°F), mortar curing slows dramatically: use heated materials and enclosures. Mortar that freezes before curing is permanently damaged.
How many bags of mortar do I need for 1,000 bricks?
For 1,000 standard modular bricks with 3/8-inch joints, you need approximately 35-40 eighty-pound bags of pre-mixed Type N mortar, or 2.25 cubic yards (60 cubic feet) of bulk mortar. This assumes standard 3/8-inch bed and head joints. Wider joints or different brick sizes will change the amount. Use our calculator above for your specific dimensions.
What is the difference between Type N, Type S, and Type M mortar?
Mortar types are defined by compressive strength: Type N (750 psi) is general-purpose for above-grade, non-load-bearing walls. Type S (1,800 psi) is for structural, below-grade, and exterior applications with higher lateral loads. Type M (2,500 psi) is for heavy-duty, below-grade, and engineered masonry. Type O (350 psi) is for interior, non-load-bearing, and historic restoration where a softer mortar is required to protect older, softer brick units.
Can I use concrete mix instead of mortar for bricklaying?
No. Concrete mix contains coarse aggregate (gravel) which makes it unworkable for thin mortar joints and prevents proper bonding with brick or block. Mortar is formulated with fine sand only and typically includes lime for workability and water retention. Using concrete for bricklaying produces weak, poorly bonded joints that will fail. Always use purpose-made mortar mix or mortar cement for masonry work.
What sand should I use for mortar?
Use clean, well-graded masonry sand (also called builders sand or plaster sand) with grains ranging from very fine to about 1/8 inch. Masonry sand should pass through a #4 sieve and have no more than 5% passing the #200 sieve (fines). Beach sand is too uniform and rounded for good mortar. Sharp, angular sand particles (from crushed stone) produce stronger mortar than rounded river sand. Wash your sand if it contains silt, clay, or organic material.