Mortar calculator

How many bags of mortar do I need for 1,000 bricks?

With Quikrete's 80 lb Mortar Mix, 1,000 bricks need 32 bags with the default extra, which is the low end of the Brick Industry Association's waste range. That is the result the calculator shows when it loads. The working: 1,000 × 1.15 = 1,150 bricks' worth of mortar, divided by the 37 bricks one bag lays, is 31.1, rounded up to 32.

The same 1,150 divided by Sakrete's 40 bricks/bag gives 29 bags of its 80 lb Type N mix. NCMA's estimate for any preblended 80 lb bag is 50 units/bag, which gives 23 bags. That spread is the main reason to choose the product in the calculator rather than rely on one rule of thumb: the yields are each maker's own figures, and they do not agree.

For metric users the default is 500 bricks laid from Tarmac's 10 kg ready-to-use tubs. A 10 kg tub of Tarmac ready-to-use Mortar Mix lays about 12 bricks. With the default extra that is 48 tubs, which is why tubs suit repairs and short garden walls rather than a house extension.

Enter the count before any breakage allowance. If you used the brick calculator or the cinder block count tool, take the "before extra" figure, not the number to buy, so the spare units do not inflate the mortar.

How is mortar quantity calculated?

Mortar is counted from the number of units each bag or batch will lay, not from the volume of the joints. Makers and trade bodies publish those yields because joint volume is hard to measure and most of the loss happens on the board and the ground. The calculator follows three routes depending on the mortar you pick.

• Bagged mortar mix or tubs: units × (1 + extra ÷ 100) ÷ units laid per bag, rounded up.
• Masonry cement and sand: NCMA's batch of 8 bags (70 lb each) of masonry cement and 2,000 lb (907 kg) of sand lays 1,000 units/batch or 240 blocks/batch. The calculator divides that by eight to get units per bag, rounds the bag count up, then adds an eighth of the batch's sand per bag.
• Portland cement, hydrated lime and sand: each NCMA batch starts from 1 cu ft of cement, with the lime and sand set by the mortar type. Units ÷ units per batch gives the batches, and each ingredient is batches × its amount per batch.

Worked example: Type S site mix for 1,000 bricks

With no extra, 1,000 bricks ÷ the 225 units/batch a Type S batch lays = 4.44 batches. Cement: 4.44 × 1 = 4.44 cu ft (126 L). Lime: 4.44 × 0.5 = 2.22 cu ft (63 L). Sand: 4.44 × 4.5 = 20 cu ft (566 L). The amounts are loose volumes, measured by the bucket or box, not weights.

Worked example: masonry cement for 500 bricks

One 70 lb bag of masonry cement lays 1,000 ÷ 8 = 125 bricks in NCMA's batch. So 500 bricks need 4 bags, and 4 × 250 lb = 1,000 lb of masonry sand, half a short ton. Quikrete's own figure for the same bag is higher. A 70 lb bag of masonry cement mixed with sand lays about 46 blocks or 144 bricks (Quikrete) or about 30 hollow blocks (NCMA). The calculator uses NCMA's because it states the sand too, and its lower yield is the safer side to be on.

Illustration sources

• Concrete Masonry & Hardscapes Association (formerly NCMA) — TEK 04-02A Estimating Concrete Masonry Materials
• The Quikrete Companies — QUIKRETE Masonry Cement (Type N) Data Sheet
• The Quikrete Companies — QUIKRETE Masonry Cement (Type S) Data Sheet

How many bricks or blocks does each mortar product lay?

An 80 lb bag of pre-sanded Type N mortar lays between 37 bricks/bag and 50 units/bag, depending on whose figure you use. The table sets each yield the calculator uses beside its source. Blocks use far more mortar per unit than bricks, because each block has a much larger bed and head joint, so a bag lays far fewer blocks than bricks.

A common mix-up is to treat a bag of mortar mix and a bag of masonry cement as the same thing. Mortar mix already contains its sand; you add only water. Masonry cement is the binder alone and must be mixed with several times its volume of sand. Quikrete mixes 1 part masonry cement with 2 1/4 to 3 parts masonry sand for mortar. That is why one bag of masonry cement lays several times as many bricks as one bag of mortar mix, and why the calculator lists sand only for the masonry cement and site-mix routes.

Which mortar type should I choose: M, S, N or O?

Type N is the default for most above-ground walls, and Type S for work at or below ground. ASTM C270's selection guide recommends Type N for above-grade load-bearing walls, inside and out, and Type S for foundations, retaining walls, paving and patios. The letters set a minimum strength, which ASTM C270 lists as 2,500 psi (17.2 MPa) for Type M, 1,800 psi (12.4 MPa) for S, 750 psi (5.2 MPa) for N and 350 psi (2.4 MPa) for O (Concrete Masonry & Hardscapes Association (formerly NCMA) and The Quikrete Companies).

Stronger is not automatically better. NCMA and Quikrete both point readers to the selection guide in ASTM C270 rather than to the strongest type. Use the type the guide, your drawings or your local code calls for.

The type affects the calculator in two ways. In site-mix mode it sets the lime and sand per batch, so Type O, with the most lime and sand, lays the most units per batch of cement. With a bagged product, the bag is one type only: if you choose Type S while a Type N bag is selected, the calculator keeps the count but adds a note telling you to buy a Type S product and check its own yield. For concrete mixes and mortar proportions on one page, see which concrete mix for which job.

How much extra mortar should I allow?

The Brick Industry Association's rule is to add 15 to 25 percent to net mortar. Add 15-25% to net mortar quantities for waste. The calculator starts at the low end and lets you raise it. Mortar waste runs higher than brick waste because it is lost in ways that do not show up in a count: it dries on the board, drops from the trowel, and gets scraped off the face when joints are struck.

Choose the higher end for hot, windy days, when mortar stiffens on the board before it is used; for first-time bricklayers; and for walls with lots of cuts and short runs. Keep the low end for long straight runs laid by someone practised. The bag yields from Quikrete and Sakrete describe ideal laying, so they make no allowance of their own. The NCMA batch tables are different: the masonry cement figures already include waste, which is one reason they sit lower than the maker's. To compare mortar with other materials, see the waste percentage by job guide.

Hydrated lime has become notably dearer, which is worth knowing before you choose the site-mix route on cost. The US Geological Survey's Mineral Commodity Summaries 2026 put the average US plant value of hydrated lime at 280 USD per metric ton in 2025, well above its 2021 level. That is a producer value, not a store price, but it shows the direction.

What changes for UK and metric mortar?

In the UK, mortar is named by designation or strength class rather than by letter. UK mortar designations (i) to (iv) correspond to strength classes M12, M6, M4 and M2. Designation (iii), class M4, the usual general-purpose UK mortar, is 1:1:5-6 cement:lime:sand by volume. The table gives the full set of proportions. The calculator's site-mix route uses NCMA's US batches, not these, so for a UK site mix use the proportions below and the per-tonne yield instead.

MPA says 1 tonne of cement:lime:sand mortar lays about 1,000 bricks or 600 blocks of 450 x 225 x 100 mm. For tubs, the calculator uses Tarmac's figure. We found no printed brick or block count for any UK 20 kg or 25 kg bag of dry mortar from Tarmac, Blue Circle or Hanson, so those bags are not offered. Blue Circle does print a water figure: Blue Circle Quality Assured Mortar takes about 4 litres of water per 20 kg bag.

Sand is the bulk of any mortar, and supply has tightened. Great Britain sales of sand and gravel fell to 40.97 million tonnes in 2025 from 53.77 million in 2021, with 17.09 million tonnes sold as sand for concreting, per DBT Table 4b. Brick use has moved the other way in the latest year. Great Britain brick deliveries were 1,481 million bricks in 2025, up from 1,401 million in 2024 but below 2,050 million in 2018, per DBT Table 9c.

In metric mode the calculator's sand figure for masonry cement is shown in kilograms, and site-mix volumes are shown in litres beside cubic feet.

When is the mortar result wrong or not enough?

The calculator counts mortar for the bed and head joints of a single skin of ordinary bricks or blocks. These cases need more:

• Collar joints. In a double-skin wall with the gap between skins filled solid, the filled joint needs its own mortar. BIA's table below gives that volume per 100 sq ft; it is not in the bag yields.
• Header bonds. English, Flemish and garden-wall bonds use more bricks and more mortar than running bond. Count the bricks with the bond in mind first, then enter that count.
• Joints wider than usual. Bag yields assume normal joints. With 3/8 in joints, 1,000 modular bricks take about 8.1 cu ft (0.23 m³) of mortar before waste; 10.3 cu ft at 1/2 in joints. Wider joints use more per brick, so raise the extra if your joints are wide.
• Large or unusual units. Yields are for standard bricks and conventional 8 in blocks, or UK 100 mm blocks for the tub. Jumbo bricks, thick blocks and stone need their own figures.
• Parging, pointing and render. Coating or repointing a wall is not laying it. Those jobs need area-based coverage from the product's data sheet.

One cubic foot (or m³) of loose, damp sand yields about one cubic foot (or m³) of mortar. That is a handy cross-check: if a site mix result seems off, the sand volume should be close to the mortar volume your joints need.

Illustration sources

• Brick Industry Association — Technical Note 10: Dimensioning and Estimating Brick Masonry (Feb 2009)

Which calculator do I need next?

Mortar is the second step: the unit count comes first. The brick calculator uses BIA's per-area figures for eight US brick sizes plus the UK standard brick, and the cinder block count tool covers US and UK blockwork with core grout. If you would rather check the arithmetic yourself, the guide to calculating bricks by hand sets it out step by step.

The full set of concrete and masonry calculators sits on one category page. For the bigger picture on cement and lime, see the cement production and consumption data.

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