Professional Mortar Calculator - Calculate Mortar for Brick, Block & Stone Masonry
Calculate mortar quantities for brick walls, block walls, stone masonry, and pointing projects. Get accurate estimates for bags of mortar, cement, sand, and lime based on wall dimensions, unit size, joint thickness with support for Type N, S, M, and O mortar mixes.
Wall & Unit Specifications
Choose how to specify project size
Select masonry unit type
Total wall surface area
Standard: 3/8" brick, 1/2" block
Wall thickness configuration
Standard 10-15% for spillage and waste
Mortar Volume:
6.66 ft³
656 units
Mortar Mix & Pricing
Selected Mortar Type
Type N (750 psi) - General purpose mortar for above-grade walls
Choose mortar supply method
Additional Costs
Bags Required:
10 bags
Results & Cost Analysis
Project Summary
Material Quantities
Cost Breakdown
Unit Costs & Metrics
Mortar Mix Information
Mix ratio 1:1:6 (cement:lime:sand). Most versatile mortar balancing strength and workability for residential construction.
Last updated: November 4 2025
Curated by the QuickTooly Team
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What Is a Mortar Calculator? Complete Guide to Masonry Mortar Estimation
A mortar calculator is a professional tool for accurately estimating mortar quantities needed for brick, block, and stone masonry projects. This comprehensive calculator determines material requirements for walls, foundations, chimneys, and pointing work by calculating mortar volume based on wall dimensions, unit size, joint thickness, and mortar type. Support for Type N, S, M, and O mortar ensures accurate estimates for any masonry application from general purpose to high-strength structural work.
Our advanced mortar calculator handles standard bricks, modular bricks, cinder blocks, concrete blocks, natural stone, and custom units. Calculate by wall area or number of units, choose between pre-mixed mortar bags or separate cement/sand/lime components, account for single or double wythe walls, include waste factors for realistic ordering, and get complete cost analysis with labor and delivery. Perfect for masons, contractors, estimators, and DIY builders planning masonry projects.
Why Use Our Professional Mortar Calculator?
- Accurate Mortar Estimation: Precise calculations for mortar volume based on wall area, unit dimensions, and joint thickness. Accounts for bed joints (horizontal) and head joints (vertical) in masonry construction.
- Multiple Mortar Types: Support for Type N (general purpose), Type S (high strength), Type M (very high strength), and Type O (low strength). Each type has specific mix ratios and applications for different masonry needs.
- Flexible Material Options: Calculate for pre-mixed mortar bags or separate materials (Portland cement, masonry sand, hydrated lime). Choose based on project size, mixing capability, and cost considerations.
- Standard and Custom Units: Pre-loaded dimensions for standard bricks, modular bricks, cinder blocks, and concrete blocks. Custom size option for specialty units, stone, or regional variations in masonry unit sizes.
- Complete Cost Analysis: Detailed cost breakdown for mortar materials (bags or components), labor per area, delivery charges, and total project cost. Compare pre-mix vs. separate materials costs for budget optimization.
Mortar Types: Complete Selection Guide (ASTM C270)
- Type N Mortar (General Purpose - 750 psi): Most common mortar for above-grade exterior and interior walls. Mix ratio 1:1:6 (cement:lime:sand). Medium strength balanced with good workability and bonding. Suitable for residential brick walls, garden walls, chimneys above roof line, and non-structural applications. Good weather resistance and flexibility. Easier to work than higher-strength types. Standard choice for most residential masonry where high strength not required.
- Type S Mortar (High Strength - 1800 psi): High-strength mortar for below-grade applications and structural masonry. Mix ratio 1:0.5:4.5 (cement:lime:sand). Excellent for retaining walls, foundations, brick pavements, manholes, and sewers. Superior lateral strength for applications subject to soil pressure. Good bond strength and weather resistance. Standard for masonry exposed to severe weather or requiring high flexural bond strength. More difficult to work than Type N.
- Type M Mortar (Very High Strength - 2500 psi): Highest compressive strength mortar for heavy loads and harsh conditions. Mix ratio 1:0.25:3 (cement:lime:sand). Used for foundations, retaining walls, driveways, walkways, and structures below grade. Required for masonry exposed to severe freeze-thaw cycles with earth contact. Not recommended for residential walls - excess strength can cause cracking in softer units. Limited workability and bond strength despite high compressive strength.
- Type O Mortar (Low Strength - 350 psi): Low-strength, high-lime mortar for interior non-load-bearing applications. Mix ratio 1:2:9 (cement:lime:sand). Used for interior walls, historic restoration (matching old lime mortars), and non-structural partitions. Excellent workability and water retention. Soft mortar protects softer historic bricks from damage. Not suitable for exterior use or structural applications. Very slow strength gain requiring extended curing time.
Mortar Mix Proportions: Understanding Cement, Lime & Sand Ratios
Mortar mix proportions determine strength, workability, and durability. Ratios expressed as cement:lime:sand by volume. More cement increases strength but reduces workability. More lime improves workability and water retention. Sand provides bulk and reduces shrinkage.
Type M: 1:0.25:3 (Portland cement:lime:sand)
Highest cement content produces 2500 psi compressive strength. Very stiff mix difficult to work. Limited workability requires skilled mason. Poor bond strength despite high compression. Use only where specifications require high compressive strength like foundations bearing heavy loads. Harsh mix can damage softer masonry units. Minimal lime provides little workability benefit.
Type S: 1:0.5:4.5 (Portland cement:lime:sand)
High cement with moderate lime balances strength (1800 psi) and workability. Most popular for structural applications. Good bond strength and weather resistance. Suitable for below-grade work, retaining walls, pavements, and severe exposure conditions. Workable enough for most masons while providing required strength. Standard for CMU (concrete masonry unit) construction and brick veneer over frame.
Type N: 1:1:6 (Portland cement:lime:sand)
Balanced mix producing 750 psi - adequate for most residential work. Equal cement and lime provides good workability with sufficient strength. Easiest to work of structural mortars. Excellent bond to brick and block. Standard for above-grade exterior walls, interior walls, and non-structural masonry. Good freeze-thaw resistance. Most economical choice for general masonry work.
Type O: 1:2:9 (Portland cement:lime:sand)
High lime content (350 psi) for maximum workability. Very soft mortar protects soft historic bricks. Excellent for restoration matching old lime mortars. Not for exterior or structural use - insufficient strength and weather resistance. Long working time and easy repointing. High water retention prevents premature drying. Used only where low strength specifically required or mandated for historic preservation.
Mortar Joint Thickness: Standards and Applications
Mortar joint thickness affects structural performance, appearance, and mortar quantity. Standard bed joint (horizontal) thickness 3/8" (10mm) for brick, 1/2" (13mm) for block. Head joints (vertical) typically same thickness. Thicker joints require more mortar and reduce wall strength. Thinner joints difficult to properly fill.
3/8" (10mm) - Standard for Brick Masonry
Most common bed joint thickness for brick construction per building codes. Provides adequate mortar cushion for brick size variations. Achieves good bond without excess mortar. Standard modular brick designed for 3/8" joints achieving 8" module with three courses. Adequate thickness for proper tooling and weatherproofing. Not suitable for blocks - too thin for large units.
1/2" (13mm) - Standard for Block Masonry
Standard bed joint for concrete block (CMU) and large format units. Thicker joint accommodates block size variations better than brick. Provides structural cushion for heavier units. Achieves 8" module with standard 8" high blocks. Easier to achieve full mortar coverage on wider block face shells. Required thickness for proper adhesion and structural performance with blocks.
1/4" (6mm) - Thin Joints
Thin joints for precision-ground units or architectural effect. Requires precisely sized units with minimal variation. Difficult to spread evenly and achieve full coverage. Reduced mortar cushion provides less accommodation for unit variation. Higher skill level required for consistent installation. Creates refined appearance emphasizing units over joints. Not recommended for standard bricks or blocks.
5/8" (16mm) - Thick Joints
Thick joints for irregular stone, salvaged bricks, or rustic appearance. Accommodates significant size variations in handmade or salvaged units. Uses more mortar per square foot. Creates strong visual element in rustic or traditional designs. Common in historic masonry and restoration work. Easier to fill completely than thin joints. Lower structural efficiency than standard joints.
How to Calculate Mortar Quantity for Masonry Projects
Calculating mortar quantity requires knowing wall area, unit size, and joint thickness. Mortar fills spaces between units (bed and head joints) plus mortar bed variations. Standard method calculates units per square foot, then mortar volume per unit.
Step 1: Calculate Wall Area
Measure wall length × height for total area. Example: 20 ft long × 8 ft high = 160 square feet. Subtract openings (windows, doors) from total. For multiple walls, calculate each and sum areas. Add 10% waste factor: 160 × 1.10 = 176 sq ft for material ordering.
Step 2: Determine Units per Square Foot
Standard modular brick (3-5/8" × 2-1/4" × 8" with 3/8" joints): 7 bricks per square foot. Standard 8" concrete block (7-5/8" × 15-5/8" with 1/2" joints): 1.125 blocks per square foot. For custom units: calculate unit area including one joint width on length and height, convert to square feet, divide into 1 square foot.
Step 3: Calculate Mortar Volume per Unit
For brick: bed joint area = (8" + 0.375") × 0.375" × 2.25" deep. Head joint area = 2.25" × 0.375" × 3.625" deep. Total ≈ 8 cubic inches mortar per brick. For 8" block: bed joints on two face shells plus head joint ≈ 80 cubic inches per block. Convert to cubic feet: divide by 1728.
Step 4: Calculate Total Mortar Volume
Multiply units per square foot × mortar per unit × total square feet. Example brick wall: 7 bricks/sf × 8 cu in/brick × 176 sf = 9856 cu in = 5.7 cubic feet. Add 10% waste: 5.7 × 1.1 = 6.3 cubic feet. For block: 1.125 blocks/sf × 80 cu in/block × 176 sf = 15,840 cu in = 9.2 cubic feet.
Step 5: Convert to Bags
Pre-mixed mortar: 80 lb bag covers ~35-40 bricks or 12-15 blocks. Calculate bags = total units ÷ coverage. Round up. For separate materials: Type N mix 1:1:6 requires 1 bag cement + 1 bag lime + 21 cu ft sand per ~400 bricks. Scale proportionally for project size.
Pre-Mixed Mortar vs. Separate Materials: Which to Choose?
- Pre-Mixed Mortar Bags (Dry Mix): Cement, lime, and sand pre-proportioned in correct ratios - just add water. Advantages: Guaranteed consistent mix, no calculations needed, convenient for small projects, available in all mortar types, reduced labor mixing. Disadvantages: Higher cost per unit volume (2-3x vs. separate materials), limited to bag sizes, requires storage space, heavier to transport. Best for: DIY projects, small jobs under 500 units, when consistency critical, no mixer available.
- Separate Materials (Field Mixed): Purchase Portland cement, hydrated lime, and masonry sand separately, mix on site. Advantages: Significantly lower cost for large projects, bulk sand delivery economical, adjust proportions if needed, purchase only quantities needed. Disadvantages: Requires mixer equipment, must measure proportions accurately, consistency varies by mixing, more labor intensive, weather affects mixing. Best for: Commercial projects, jobs over 1000 units, contractors with mixing equipment, when cost critical.
- Cost Comparison Example: 1000 standard brick wall requires ~28 bags (80lb) pre-mixed mortar at $8/bag = $224 materials. Same wall with separate materials: 5 bags cement ($60), 5 bags lime ($50), 1.5 tons sand ($45) = $155 materials + mixer rental/ownership. Labor mixing adds 2-4 hours. Pre-mix saves labor, separate materials save money on large projects.
- Quality Considerations: Pre-mixed bags ensure consistent strength meeting ASTM C270 specifications. Field-mixed mortar requires accurate measuring - incorrect ratios compromise strength and durability. Volume batching (shovels, buckets) less accurate than weight batching. Commercial projects often require pre-mixed or certified batch plant mortar for quality control. DIY projects benefit from pre-mix simplicity reducing errors.
Common Mortar Mixing and Application Mistakes
- Using Wrong Mortar Type: Using Type M (very high strength) for above-grade walls causes cracking - mortar stronger than brick restrains natural movement. Using Type O (low strength) for foundations or retaining walls leads to structural failure. Type N suitable for most residential above-grade work. Type S for below-grade, retaining walls, and harsh exposure. Match mortar strength to application.
- Adding Excess Water: Wet soupy mortar easier to spread but dramatically reduces strength, increases shrinkage, and causes efflorescence. Every extra quart of water per bag reduces compressive strength 25-40%. Mortar should be workable but hold shape on trowel. Add water gradually, remix rather than adding water to restore workability as mortar stiffens.
- Incorrect Joint Tooling Timing: Tooling too early when mortar soft smears face and weakens joint. Tooling too late when mortar hard causes cracking and poor finish. Tool when thumbprint leaves slight impression - typically 30-60 minutes after laying depending on temperature and humidity. Proper timing creates watertight compressed joint surface.
- Insufficient Joint Filling: Shallow butter on brick ends creates voids in head joints allowing water penetration. Incompletely filled bed joints reduce wall strength. Mortar should fill entire joint depth. Furrow bed joint before laying brick to ensure mortar contacts entire unit. Cut brick carefully to avoid breaking mortar bond in adjacent joints.
- Working in Wrong Temperatures: Laying masonry below 40°F causes mortar to freeze before setting, destroying bond and strength. Working above 90°F causes rapid water loss preventing proper hydration. Cold weather requires heated sand/water and insulated curing. Hot weather requires dampening units, shading work, and frequent mortar remixing. Ideal temperature range 50-80°F.
- Not Protecting Fresh Masonry: Rain on fresh mortar (first 24-48 hours) washes out cement, weakens joints, and causes staining. Freeze before initial set destroys bond permanently. Cover new work with tarps supported to prevent contact with masonry. Maintain coverage minimum 48 hours or until mortar reaches working strength.
Frequently Asked Questions About Mortar Calculation
How many bags of mortar do I need for 100 square feet?
Depends on unit type and size. For standard brick wall (7 bricks per sf): approximately 4-5 bags of 80 lb pre-mixed mortar per 100 sf. For 8" concrete blocks (1.125 per sf): approximately 9-10 bags per 100 sf. Thicker joints, larger units, or double wythe walls increase requirements. Add 10% waste factor.
What is the best mortar type for brick walls?
Type N (750 psi) best for most residential brick walls above grade - balanced strength and workability. Type S (1800 psi) for foundations, retaining walls, below-grade work, or severe weather exposure. Type M (2500 psi) only when specifications require very high compressive strength. Avoid Type M for standard walls - excess strength causes cracking in softer bricks.
How long does mortar take to cure?
Initial set: 24-36 hours when mortar hardens enough to resist rain and light loads. Working strength: 7 days reaches 60-70% of final strength, safe for wall loading. Full cure: 28 days for specification strength testing. Cold weather slows curing significantly. Hot weather accelerates but may compromise strength if water evaporates too fast.
Can I use leftover mortar from yesterday?
No - never retemper mortar after initial set begins (usually 90-120 minutes). Adding water to stiffened mortar severely compromises strength even if restored to workable consistency. Discard unused mortar when it becomes too stiff to work properly. Mix only amount usable within 90 minutes. Pre-mixed dry bags last indefinitely if kept dry.
Should mortar be stronger than the brick?
No - mortar should be softer and weaker than brick. Hard mortar prevents natural thermal movement causing brick cracking. If repairs needed, replacing weaker mortar cheaper and easier than replacing damaged bricks. Type N (750 psi) softer than most bricks (3000-8000 psi) while providing adequate strength for walls. Mortar acts as sacrificial element absorbing stress.
What causes white stains on new brick (efflorescence)?
Efflorescence occurs when water-soluble salts migrate through masonry and crystallize on surface. Causes: excess water in mortar, rain on fresh work, ground water wicking up wall, poor drainage. Prevention: use correct water content, protect from rain 48 hours, install proper flashing and weep holes, damp-proof below grade. Usually disappears naturally with weathering.
How thick should mortar joints be?
Standard 3/8" (10mm) for brick masonry both bed and head joints. Standard 1/2" (13mm) for concrete block. Thinner joints (1/4") require precision units and skilled installation. Thicker joints (5/8"+) for irregular stone or rustic appearance. Building codes specify maximum joint thickness for structural calculations. Consistent thickness critical for appearance and structural performance.
Do I need to wet bricks before laying?
Yes for porous clay bricks in hot dry weather - spray lightly so surface damp but not dripping. Prevents brick from sucking water out of mortar too quickly, which weakens bond. Don't wet in cool weather or with low-absorption bricks. Never lay saturated bricks - causes mortar to slide and slump. Concrete blocks should not be wetted - can cause shrinkage cracks.
Start Your Masonry Project with Accurate Mortar Calculations
Use our professional mortar calculator to accurately estimate mortar quantities for your brick, block, or stone masonry project. Accurate material calculations prevent work stoppages from running short and reduce waste from over-ordering. Whether building residential walls, foundations, retaining walls, or chimneys, knowing exact mortar requirements saves money and ensures quality results. Select appropriate mortar type for your application (Type N, S, M, or O), choose between pre-mixed bags or separate materials based on project size, account for realistic waste factors, and follow proper mixing and curing procedures. Quality materials, correct proportions, proper application technique, and adequate curing produce strong, durable masonry that lasts for generations.