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Mortar Calculator

Estimate mortar volume, brick or concrete block quantities, cement bags, and sand requirements for masonry projects. Supports standard and custom mortar mix ratios.

CalculatorHow to CalculateFormulas & ExamplesFAQs

Select a wall type, input project dimensions, and click Calculate.

Wall Dimensions

Brick Dimensions

Joint & Waste

10%

Mix Ratio & Cement Bag Options

Calculation Results

Awaiting Calculations

Fill in the wall dimensions, select materials, and click Calculate to view exact materials estimates.

Formula Details

Wall Area & Volume Formula
Area = Length × Height | Volume = Area × Thickness

Calculates the front-facing surface area and overall space of the wall. Dimensions are normalized to feet or meters before calculations.

Variables Explained
  • Length
    Wall Length:The horizontal span of the wall.
  • Height
    Wall Height:The vertical height of the wall.
  • Thickness
    Wall Thickness:The depth or width of the wall structure.
Brick / Block Count Formula
Required Count = ceil( (Wall Volume / ((Brick Length + Joint) × (Brick Height + Joint) × Brick Width)) × (1 + Waste / 100) )

Estimates the number of bricks or blocks needed by dividing the total wall volume by the nominal volume of a single brick (which includes its mortar joints).

Variables Explained
  • Brick Length & Height
    Brick Dimensions:The actual length and height of a single brick/block.
  • Brick Width
    Brick Width:The thickness of the block/brick.
  • Joint
    Mortar Joint Thickness:The thickness of the mortar layer (usually 3/8" or 10 mm).
Mortar Volume Formula
Mortar Volume = Wall Volume - (Bricks Count × (Brick Length × Brick Height × Brick Width))

Finds the net wet mortar volume by subtracting the combined physical volume of all actual solid bricks/blocks from the overall volume of the wall structure.

Variables Explained
  • Bricks Count
    Raw Brick Count:The raw, fractional number of bricks calculated for the wall.
  • Brick dimensions
    Actual Brick Volume:The volume occupied by a single physical brick without mortar.
Cement & Sand Quantities
Dry Volume = Wet Volume × 1.33 | Cement Vol = Dry Vol × (C / (C + S)) | Sand Vol = Dry Vol × (S / (C + S))

Applies a standard dry factor of 1.33 to wet mortar volume to account for dry material shrinkage and void compaction, then distributes dry volumes according to the mix ratio.

Variables Explained
  • C & S
    Mix Ratio Parts:The parts of cement and sand (e.g. 1 part cement to 4 parts sand).
  • Dry Volume
    Compacted Dry Mortar:The volume occupied by dry ingredients prior to mixing with water.

Calculation Example

Worked Example
Scenario

Calculate brick, mortar, cement, and sand requirements for a brick wall that is 15 feet long, 6 feet high, and 3.75 inches thick, using standard US bricks (8" x 2.25" x 3.75"), a 3/8" mortar joint, 10% waste, and a 1:4 (Type S) mix ratio.

Calculation Steps
  1. 1.Convert all dimensions to feet.
    Wall = 15 ft × 6 ft × 0.3125 ft | Brick = 0.6667 ft × 0.1875 ft × 0.3125 ft | Joint = 0.03125 ft
  2. 2.Calculate total Wall Volume.
    15 ft × 6 ft × 0.3125 ft = 28.125 ft³
  3. 3.Calculate bricks needed using nominal brick volume.
    Nominal Brick Vol = (0.6667 + 0.03125) × (0.1875 + 0.03125) × 0.3125 = 0.0478 ft³ | Raw bricks count = 28.125 / 0.0478 = 589.5 bricks. With 10% waste: ceil(589.5 × 1.1) = 649 bricks.
  4. 4.Calculate net wet mortar volume.
    Net Mortar Vol = Wall Vol - (Raw Bricks × Actual Brick Vol) = 28.125 - (589.5 × (0.6667 × 0.1875 × 0.3125)) = 28.125 - 23.027 = 5.098 ft³
  5. 5.Add 10% waste and convert to dry volume.
    Wet Vol with Waste = 5.098 × 1.1 = 5.608 ft³ | Dry Vol = 5.608 × 1.33 = 7.459 ft³
  6. 6.Estimate cement bags and sand volume (1:4 ratio).
    Cement Vol = 7.459 × (1 / 5) = 1.492 ft³ | Cement Weight = 1.492 × 94 lbs/cft = 140.2 lbs | Bags (94 lb bag) = ceil(140.2 / 94) = 2 Bags | Sand Vol = 7.459 × (4 / 5) = 5.967 ft³ (~0.22 yd³)
Final Quantity Needed649 Bricks, 5.61 ft³ Mortar, 2 Cement Bags, 5.97 ft³ Sand
Worked Example
Scenario

Calculate concrete blocks, mortar, cement, and sand requirements for a block wall that is 30 feet long, 8 feet high, and 7.625 inches thick, using standard CMU blocks (15.625" x 7.625" x 7.625"), a 3/8" joint, 10% waste, and a 1:4 mix ratio.

Calculation Steps
  1. 1.Convert all dimensions to feet.
    Wall = 30 ft × 8 ft × 0.6354 ft | Block = 1.3021 ft × 0.6354 ft × 0.6354 ft | Joint = 0.03125 ft
  2. 2.Calculate total Wall Volume.
    30 ft × 8 ft × 0.6354 ft = 152.5 ft³
  3. 3.Calculate blocks needed using nominal block volume.
    Nominal Block Vol = (1.3021 + 0.03125) × (0.6354 + 0.03125) × 0.6354 = 0.5647 ft³ | Raw blocks count = 152.5 / 0.5647 = 270 blocks. With 10% waste: ceil(270 × 1.1) = 297 blocks.
  4. 4.Calculate net wet mortar volume.
    Net Mortar Vol = Wall Vol - (Raw Blocks × Actual Block Vol) = 152.5 - (270 × (1.3021 × 0.6354 × 0.6354)) = 152.5 - 141.87 = 10.63 ft³
  5. 5.Add 10% waste and convert to dry volume.
    Wet Vol with Waste = 10.63 × 1.1 = 11.69 ft³ | Dry Vol = 11.69 × 1.33 = 15.55 ft³
  6. 6.Estimate cement bags and sand volume (1:4 ratio).
    Cement Vol = 15.55 × (1 / 5) = 3.11 ft³ | Cement Weight = 3.11 × 94 lbs/cft = 292.3 lbs | Bags (94 lb bag) = ceil(292.3 / 94) = 4 Bags | Sand Vol = 15.55 × (4 / 5) = 12.44 ft³
Final Quantity Needed297 Blocks, 11.69 ft³ Mortar, 4 Cement Bags, 12.44 ft³ Sand

How to Use

Follow these simple steps to estimate the quantities of mortar, brick/block, and mixing components for your project:

  1. Choose Wall Type: Select either Brick Wall or Concrete Block Wall. This automatically updates default dimensions to match industry standards.
  2. Select Unit System: Toggle between Imperial (feet and inches) and Metric (meters, centimeters, and millimeters) at the top of the calculator.
  3. Enter Wall Dimensions: Input your wall length, height, and thickness in the chosen units.
  4. Configure Masonry Sizes & Joint: Enter the physical length, height, and width of your individual bricks or blocks, as well as the thickness of your mortar joint (default is 3/8" or 10 mm).
  5. Choose Mix Ratio & Bag Weight: Adjust the mix ratio dropdown (Type M, S, N, O, or Custom) and select your preferred cement bag size to compute custom bag counts.
  6. Set Waste Factor: Use the slider to add a waste margin (10% is standard to account for spillages and cuts).
  7. Click Calculate: Review the results showing total bricks required, wet mortar volume, and separate cement bags and sand counts.

Frequently Asked Questions

How much mortar do I need for a brick wall?
On average, a standard single-wythe brick wall requires approximately 5 to 6 cubic feet of wet mortar per 100 square feet of wall area (using a standard 3/8 inch mortar joint and standard 8" bricks). If using concrete blocks, a wall requires about 10 to 12 cubic feet of mortar per 100 square feet. This calculator determines the exact volume based on your specific block, joint, and wall dimensions.
What mortar joint thickness should I use?
The standard mortar joint thickness for structural and aesthetic masonry is 3/8 inch (approximately 10 mm). This thickness provides optimal bonding strength and accounts for minor variances in brick or block sizes. Thicker joints (e.g., 1/2 inch) require significantly more mortar volume and can decrease structural stability if not done properly.
Why does the dry mortar volume factor equal 1.33?
When dry ingredients (cement and sand) are mixed with water, the fine cement particles fill the air voids between the sand grains, causing the volume to shrink. To yield 1 cubic foot of wet, mixed mortar, you need approximately 1.33 cubic feet of dry, unmixed materials. This compaction loss is standard in construction planning.
Should I include waste in my calculations?
Yes. Masonry projects experience significant mortar waste due to dropping wet mix during troweling, filling head and bed joints, and leftover mix that cures before placement. Adding a 10% to 15% waste allowance ensures you do not run out of mortar or bricks mid-project.
What mortar mix ratio is recommended?
Standard mortar mix ratios are specified by ASTM C270 types. Type N (1:5 ratio of cement to sand) is highly recommended for general residential and non-load-bearing exterior walls. Type S (1:4 ratio) has higher compressive strength and is ideal for structural walls, foundations, sewers, and patios. Type M (1:3 ratio) is the strongest and is reserved for heavy load-bearing structures.

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Disclaimer

Calculations are estimates based on the values you enter and standard engineering formulas. Results are intended for planning and estimation only. Always verify critical measurements, specifications, and local building requirements before purchasing materials or beginning construction.