Mortar Calculator
ConstructionCalculate how many 80 lb bags of mortar mix you need for your brick or block project. Enter brick count and mortar volume per joint to get the bag count.
Bags Needed
3
Total Mortar Volume
2.6
What is a Mortar?
A mortar calculator determines how many bags of mortar mix are needed to complete a brick or block masonry project, based on the total number of units being laid and the volume of mortar consumed per joint. Mortar is the cement-based binding paste applied between bricks, blocks, or stones to hold them together structurally — unlike grout, which fills the narrow gaps between finished tile. Because mortar volume scales directly with brick count and joint thickness, small changes in joint size or brick dimensions can significantly shift the total bags needed.
This tool converts your project's brick count and per-brick mortar volume into a total volume in cubic feet, then divides by your mortar bag's coverage yield to output a ready-to-buy bag count. It's a natural companion to the Brick Calculator for figuring out total brick quantity first, and the Grout Calculator for finished tile work.
How to use this Mortar calculator
- Enter the total Number of Bricks for your project — count each brick or block individually, not by wall area.
- Set Mortar per Brick in cubic inches based on your joint thickness; 4.5 cubic inches is a reasonable default for standard 3/8-inch joints.
- Adjust Bag Yield if your mortar mix brand's coverage differs from the standard 1 cubic foot per 80 lb bag — check the bag label for the exact figure.
- Review the Bags Needed result to know exactly how many bags to purchase.
- Check Total Cubic Feet if you're comparing against bulk mortar delivery pricing instead of bagged mix.
- Add roughly 10% extra bags to your final order to cover spillage and mixing waste on-site.
Formula & Methodology
The calculator converts brick count and per-joint mortar volume into a bag count using the following steps: Total mortar volume (cu in) = Number of bricks × Mortar per brick (cu in) Total cubic feet = Total mortar volume ÷ 1728 Bags needed = ceiling(Total cubic feet ÷ Bag yield in cu ft) Worked example: For 1,000 bricks using 4.5 cubic inches of mortar per joint and an 80 lb bag yielding 1 cubic foot: Total mortar volume = 1,000 × 4.5 = 4,500 cu in. Total cubic feet = 4,500 ÷ 1728 ≈ 2.6 cu ft. Bags needed = ceiling(2.6 ÷ 1) = 3 bags.
Frequently Asked Questions
A mortar calculator estimates how many bags of mortar mix are needed to lay a given number of bricks or blocks, based on the volume of mortar used per joint. It converts your total brick count and mortar-per-joint volume into a bag count, so you can order the correct amount of material before starting a masonry project.
The calculator multiplies the number of bricks by the mortar volume used per brick joint to get a total volume in cubic inches, then converts that to cubic feet. It divides the result by the coverage yield of a standard 80 lb bag and rounds up to the next whole bag.
Total mortar volume (cu in) = Number of bricks × Mortar per brick (cu in). Total cubic feet = Total mortar volume ÷ 1728. Bags needed = ceiling(Total cubic feet ÷ Bag yield in cu ft), where an 80 lb bag typically yields about 1 cubic foot of mixed mortar.
Mortar is a thicker, load-bearing paste used to bond bricks, blocks, and stone together structurally, while grout is a thinner filler used to fill the narrow joints between finished tiles. Mortar needs to hold weight and resist compression; grout mainly needs to seal and seal gaps, which is why they use different mix ratios.
A typical brick joint uses about 4 to 5 cubic inches of mortar, though this varies with joint thickness (commonly 3/8 to 1/2 inch) and brick size. Wider joints or oversized modular brick will use more mortar per unit, so adjust the 'Mortar per Brick' input if you know your project's specific joint dimensions.
Enter the total Number of Bricks in your project, then set the Mortar per Brick volume in cubic inches based on your joint thickness. Adjust the Bag Yield if your specific mortar mix brand differs from the standard 1 cubic foot per 80 lb bag, and the calculator shows the number of bags to buy.
Yes, the same volume-based formula works for concrete block as long as you adjust the 'Mortar per Brick' value to reflect the larger joint volume used per block, since blocks are bigger than standard bricks and typically use more mortar per joint. Check your block manufacturer's mortar coverage recommendation for the most accurate figure.
Using a typical 4.5 cubic inch mortar volume per brick, 1000 bricks require about 4,500 cubic inches, or roughly 2.6 cubic feet of mortar — around 3 standard 80 lb bags. Actual usage can vary with joint thickness and brick size, so always round up and buy a small buffer.
Mortar loss from spillage, mixing waste, and uneven application is common on real job sites, so most masons add 10% extra to the calculated amount. This buys a margin of safety against running short mid-project, which can cause delays waiting for a matching batch.
Yes, most 80 lb bags of mortar mix yield close to 1 cubic foot of mixed mortar, but this can vary slightly by manufacturer and mix type (Type N, S, or M mortar). Always check the bag's technical data sheet and adjust the Bag Yield input for the most accurate bag count.
Type N is a general-purpose mortar suited for above-grade, non-load-bearing walls and is the most common residential choice. Type S offers higher compressive strength for load-bearing or below-grade applications, while Type M is the strongest and used for heavy structural loads like retaining walls and foundations.
Also known as