MORTAR / GROUT BAGS
About this calculator
This mortar and grout calculator handles two of the most common masonry quantities: brick mortar in 80-pound bags (Type N or S) and tile grout in 25-pound bags. Pick a mode, enter your wall area or tile area along with the joint size, and the calculator estimates the bags to order with waste factored in. Brick math assumes modular brick at 6.86 per square foot with a 3/8-inch mortar joint and 30 bricks per 80-lb bag. Tile math computes grout volume from joint cross-section using tile size, joint width, and tile thickness — the same approach manufacturers use to publish coverage charts. ESTIMATE ONLY — verify with your supplier and the manufacturer's coverage chart for the specific product. Mortar mix classification (Type M, S, N, O) comes from ASTM C270; grout for reinforced masonry follows TMS 602.
How to use this calculator
Pick brick mortar mode for laying bricks (Type N for above-grade veneer, Type S for higher-strength applications) or tile grout mode for filling joints between installed tiles.
In brick mode, enter the wall area in ft² — the calculator returns bag count based on 6.86 modular bricks per ft² with a 3/8-inch joint, yielding about 30 bricks per 80-lb bag. In tile mode, enter the tile area, tile size, joint width (1/16" rectified through 1/4" rustic), and tile thickness. The calculator computes grout volume from joint cross-section and yields bags using 220 in³ per 25-lb bag.
Worked example
For a 200 ft² brick wall:
Bricks: 200 × 6.86 = 1,372 bricks. Bags: ⌈(1,372 ÷ 30) × 1.10⌉ = ⌈50.3⌉ = 51 bags of 80lb Type N.
At $7-$10 per bag: $360-$510 in mortar alone. Plus the 1,372 bricks at $0.50-$1.50 each = $690-$2,060 in brick. Total wall materials before labor: $1,050-$2,570.
For a 100 ft² tile floor with 12×12 tiles, 1/8" joints, 3/8" thick:
Grout volume per ft²: ((12 + 12) ÷ (12 × 12)) × 144 × 0.125 × 0.375 = 1.125 in³/ft². Total volume: 113 in³ = 0.065 ft³.
Bags needed: ⌈(113 ÷ 220) × 1.10⌉ = 1 bag of 25-lb grout. Larger floors: 500 ft² of the same tile and joint = ~3 bags.
For 4×4 tiles with 1/16" joints (mosaic): grout volume jumps to ~3 in³/ft² because there's much more joint length per area — small tiles eat grout fast.
Common mistakes & waste factors
Confusing Type N and Type S mortar. Type N is for above-grade non-load-bearing applications (interior partitions, brick veneer, chimneys). Type S is for load-bearing walls, below-grade work, and applications subject to lateral loads. Mixing them up doesn't fail the wall but uses wrong-spec materials.
Underordering grout for small tiles. Mosaic and small-format tiles (4×4 and below) need 3-5× more grout per ft² than 12×12 because of the higher joint length per area. Check the calculator's grout volume number for small tiles.
Forgetting joint depth. Tile grout fills the joint to the tile thickness. A ½-inch tile has more grout per joint than a ¼-inch tile at the same width.
Buying sanded grout for small joints. Sanded grout is for joints ≥1/8". Use unsanded grout for 1/16" joints (rectified porcelain, mosaic) — sanded grout in tight joints scratches the tile face.
Rules of thumb
Brick mortar: ~30 modular bricks per 80-lb bag at 3/8" joint. Use Type N for veneer/interior, Type S for load-bearing/below-grade.
Tile grout: 1 × 25-lb bag covers ~150 ft² of 12×12 with 1/8" joints. Coverage drops sharply for smaller tiles.
Small tiles (4×4 and below): 3-5× more grout per ft² than 12×12.
Rectified tiles (≤1/16" joints): use unsanded grout. Standard tiles (1/8"+ joints): sanded grout.
Grout sets in 30-60 minutes; plan small mixes (1/4 bag at a time) so you can finish before it firms up.
Always add 10% waste — tile grout especially, since unused grout in the bucket can't be re-mixed once it starts setting.
Common questions
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