Mortar Calculator: Bags, Volume, and Cost for Any Wall
Mortar Calculator for Brick, Block, and Tile
This mortar calculator converts your wall or floor size into cubic feet, cubic meters, US bag count, and total cost. Pick from brick, CMU block, tile thinset, mortar beds, and repointing, with every result built on ASTM C270 mortar types and an adjustable waste factor.
You need 5.91 cu ft (0.167 m³) of mortar, or 9 bags of 80 lb premix mortar, costing about $85.50 with 25% waste.
How we got there
| Step | Calculation | Result |
|---|---|---|
| Area | 10.00 ft x 8.00 ft | 80.00 sq ft (7.43 m²) |
| Bricks | 80.00 x 6.750 per sq ft | 540 |
| Wall volume | 80.00 x 0.302 ft | 24.17 cu ft |
| Brick volume | 540 x 62.2 in³ ÷ 1,728 | 19.43 cu ft |
| Net mortar | 24.17 − 19.43 | 4.73 cu ft |
| With 25% waste | 4.73 x 1.25 | 5.91 cu ft |
| Bags | 5.91 ÷ 0.67 cu ft per bag | 8.83 → 9 |
| Cost | 9 x $9.50 | $85.50 |
How to Use the Mortar Calculator
To use the mortar calculator, follow these 6 steps:
- Select the project type: brick, block, thinset, mortar bed, or repointing.
- Enter the length and height in feet or meters.
- Choose the unit size, trowel notch, bed thickness, or rake depth for that mode.
- Set the joint thickness, which defaults to 3/8 in (10 mm).
- Pick the bag product, then enter the waste factor and local bag price.
- Click Calculate Mortar to see the volume, bag count, and cost.
How the Mortar Calculator Works
The mortar calculator subtracts the volume of the units from the volume of the wall, then adds waste and divides by bag yield. The formula is:
Joint size drives the brick count. With 3/8 in joints, one modular brick takes up a face of 8 x 2-2/3 in, which puts 6.75 bricks in every square foot of wall (72.7 per m²).
Worked Example: 10 ft x 8 ft Brick Wall
| Step | Calculation | Result |
|---|---|---|
| Wall area | 10 ft x 8 ft | 80 sq ft (7.43 m²) |
| Bricks | 80 x 6.75 | 540 bricks |
| Wall volume | 80 sq ft x 0.302 ft (3-5/8 in) | 24.17 cu ft |
| Brick volume | 540 x 62.2 in³ ÷ 1,728 | 19.43 cu ft |
| Net mortar | 24.17 − 19.43 | 4.74 cu ft (0.134 m³) |
| With 25% waste | 4.74 x 1.25 | 5.92 cu ft (0.168 m³) |
| 80 lb bags | 5.92 ÷ 0.67 | 9 bags |
| Cost | 9 x $9.50 | $85.50 |
The wall needs 9 bags of 80 lb (36.3 kg) premix mortar. Partial bags round up, so the raw 8.84 becomes 9 on the result screen. Bump the waste factor to 40% if you’re laying brick for the first time.
Block (CMU) Rate
Standard 8 x 8 x 16 in CMU walls need about 3 bags of 70 lb (31.8 kg) masonry cement plus sand per 100 blocks. Expect roughly 8 cu ft (0.23 m³) of mixed mortar from that rate, with full first-course bedding already counted. Each square foot of wall takes 1.125 blocks.
How Many Bags of Mortar Do I Need? US Bag Yields
Divide your mortar volume by the bag yield printed on the label. Here are typical yields for 4 common US products:
| Bag | Weight | Typical yield |
|---|---|---|
| Premix mortar mix (Quikrete, Sakrete) | 80 lb (36.3 kg) | about 0.67 cu ft (0.019 m³) |
| Premix mortar mix | 60 lb (27.2 kg) | about 0.50 cu ft (0.014 m³) |
| Masonry cement + 3 cu ft sand | 70 lb (31.8 kg) | about 3 cu ft (0.085 m³) |
| Thinset mortar | 50 lb (22.7 kg) | 40 to 100 sq ft by notch |
Read the label first. Premix bags conform to ASTM C1714 for preblended dry mortar, while masonry cement conforms to ASTM C91, and that 70 lb sack only reaches its 3 cu ft yield once you’ve blended in the sand. Feed the printed figure into the mortar calculator for an exact count.
Which Mortar Type Do I Need?
Type N suits most above-grade brick veneer, Type S suits foundations and retaining walls, Type M suits heavy below-grade loads, and Type O suits interior non-load-bearing repointing. ASTM C270 defines 4 types:
| Type | Min. compressive strength | Cement : lime : sand | Typical use |
|---|---|---|---|
| M | 2,500 psi (17.2 MPa) | 1 : 1/4 : 3 | Below grade, heavy loads |
| S | 1,800 psi (12.4 MPa) | 1 : 1/2 : 4.5 | Foundations, CMU, patios |
| N | 750 psi (5.2 MPa) | 1 : 1 : 6 | Brick veneer, exterior walls |
| O | 350 psi (2.4 MPa) | 1 : 2 : 9 | Interior, historic repointing |
Each ratio is measured by volume. Portland cement must meet ASTM C150 and hydrated lime must meet ASTM C207, while the sand side falls under ASTM C144 for masonry aggregate. Codes pull this standard in directly, since both the International Residential Code (IRC) and The Masonry Society (TMS) 402/602 reference ASTM C270.
Type N vs Type S
Type S is stronger, while Type N is more flexible and bonds better with soft brick. Stronger isn’t automatically better. The Brick Industry Association (BIA) recommends the lowest-strength mortar that meets a wall’s structural needs, because overly hard mortar cracks brick faces, and on a typical above-grade veneer that points straight to Type N.
Premix vs Site-Mixed Mortar
Premix costs more per cubic foot but gives consistent batches, and site-mixed mortar costs less on jobs over 30 cu ft (0.85 m³). Measure every ingredient by volume on site. Shovel counts drift between batches, and that drift shows up as uneven color and strength across the finished wall. On big commercial jobs, crews skip bags entirely and run silo systems such as SPEC MIX.
Thinset, Mortar Bed, and Repointing Estimates
Thinset Coverage by Trowel Notch
A 50 lb bag of thinset covers about 40 to 100 sq ft (3.7 to 9.3 m²), depending on trowel notch. Typical coverage rates for 3 notch sizes:
| Trowel notch | Tile size | Coverage per 50 lb bag |
|---|---|---|
| 1/4 x 1/4 in square | Up to 8 in | 90 to 100 sq ft |
| 1/4 x 3/8 in square | 8 to 16 in | 60 to 70 sq ft |
| 1/2 x 1/2 in square | 16 in and larger | 40 to 45 sq ft |
Thinset grades come from the American National Standards Institute (ANSI) under A118.1, A118.4, or A118.15. Pull the data sheet for exact rates. Manufacturers such as LATICRETE, MAPEI, Custom Building Products, and TEC publish coverage per notch, and those figures take priority over this mortar calculator’s default values.
Mortar Bed Thickness
Bonded mortar beds start at 3/4 in (19 mm), and unbonded reinforced beds start at 1-1/4 in (32 mm). Those minimums come from the Tile Council of North America (TCNA) Handbook. Volume is area x thickness. A 5 x 5 ft shower floor floated at a 1.5 in average depth, for example, needs 3.1 cu ft (0.088 m³) of deck mud.
Repointing and Tuckpointing
Repointing mortar volume equals joint length x joint width x rake depth. Plan on about 6 linear feet of joints in every square foot of modular brick wall. For 3/8 in joints, rake 3/4 to 1 in (19 to 25 mm) deep.
Weather Limits and Related Calculators
Cold and Hot Weather Masonry
TMS 602 cold-weather rules apply below 40°F (4.4°C), and hot-weather rules apply above 100°F (37.8°C), or above 90°F (32.2°C) with wind over 8 mph (13 km/h). Heat the sand and mixing water before batching in winter. Summer flips the problem, so keep mixed mortar in the shade until it goes on the wall.
Related Concrete and Mortar Calculators
Use this concrete and mortar calculator suite for 4 linked tasks:
- Size the base with the concrete footing calculator.
- Count blocks with the cinder block calculator.
- Convert slab volume with the concrete yard calculator.
- Answer “how many bags of concrete do I need” with the bag calculator.
Looking for a Game Mortar Calculator?
This page estimates construction mortar, not in-game artillery. Gamers land here often. An Arma Reforger mortar calculator, Arma mortar calculator, or Squad mortar calculator converts target distance into elevation mils for titles from Bohemia Interactive and Offworld Industries, and a search for “mortar calculator Squad” turns up those tools.
FAQs
How many bags of mortar do I need for 100 bricks?
You need about 2 bags of 80 lb premix mortar for 100 modular bricks with 3/8 in joints and 25% waste. That works out to roughly 1.1 cu ft (0.031 m³).
Is mortar the same as concrete?
No. Concrete contains gravel and builds slabs and footings, while mortar contains only fine sand and bonds masonry units. For slab volume, switch to a concrete yard calculator.
What joint thickness does the calculator assume?
The default is 3/8 in (10 mm), which is the US standard for modular brick and CMU. Nonstandard units take different settings, so change the Joint field to 1/4 or 1/2 in.
Can I use Type S mortar for cinder block?
Yes. Type S is the preferred choice for cinder block foundations, retaining walls, and below-grade CMU because of its 1,800 psi strength. Run the cinder block calculator alongside this tool for unit counts.
How long can mixed mortar sit before use?
Mixed mortar must be used within 2.5 hours of mixing, per ASTM C270 and TMS 602. Retemper only to replace water lost to evaporation. Toss any batch that has stiffened.
Estimates use typical label yields and coverage rates. The figure printed on your bag or the manufacturer’s data sheet takes priority, so enter it where it differs. Partial bags always round up.
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