Cinder Block Mortar Calculator — Bags Per Wall
Estimate mortar bag count for any CMU wall. Uses the NCMA standard of one 60 lb bag of Type S mortar per 30 standard 8×8×16-inch cinder blocks.
Enter Dimensions
Recommended: 10% for standard projects
Results
Blocks Needed
199blocks
Mortar Bags
7bags
60 lb bags · 1 bag per 30 blocks (NCMA)
Wall Area
160sq ft
Blocks per Sq Ft
1.125blocks/sq ft
BIA standard for 8×16 face
Editorial Standards
Each calculator is reviewed for formula accuracy, unit consistency, and alignment with current U.S. building practices before publication. We verify outputs against published engineering references and real-world project data. Learn more about our methodology.
Mortar is the consumable that masons run out of first on a CMU job — and once you're set up on the wall, a mid-day mortar shortage idles the crew. This calculator uses the National Concrete Masonry Association (NCMA) ratio of 1 bag of 60 lb Type S mortar per 30 standard CMU blocks, then rounds up to whole bags.
For pre-mixed pricing, expect $7–$10 per 60 lb bag of Type S mortar at most U.S. suppliers in 2025. Field-mixed mortar (Portland + lime + sand) costs about 40% less but requires a mixer and graded sand on site.
How to Estimate Mortar for Cinder Blocks
Mortar bags = ⌈Block count ÷ 30⌉ × (1 + waste %). For 80 lb bags use ÷ 40 in place of ÷ 30.
Mortar Bag-Yield Reference
- 60 lb Type S bag ≈ 0.6 cu ft mortar — serves ~30 blocks.
- 80 lb Type S bag ≈ 0.85 cu ft mortar — serves ~40 blocks.
- Field-mixed Type S: 1 bag Portland + ½ bag lime + 4½ cu ft sand ≈ 4.5 cu ft mortar, serves ~225 blocks.
Frequently Asked Questions
How many bags of mortar do I need for 200 cinder blocks?
NCMA recommends ~1 bag of 60 lb Type S mortar per 30 standard 8×8×16 CMU blocks. 200 blocks ÷ 30 = 6.7, round up to 7 bags. Add 10% waste = 8 bags to be safe.
What type of mortar should I use for cinder blocks?
Type S (1800 psi) is the industry default for CMU work — required for any structural, load-bearing, or below-grade application. Type N (750 psi) is acceptable only for non-structural decorative work above grade.
Can I buy pre-mixed mortar in bags?
Yes — Quikrete, Sakrete, and Spec Mix sell pre-blended Type N and Type S mortar in 60 lb and 80 lb bags. Just add water. Bag yield: 60 lb ≈ 0.6 cu ft; 80 lb ≈ 0.85 cu ft.
How does waste affect the mortar estimate?
Plan 10% waste for straight walls and 15–20% for walls with corners, openings, or pilasters. Field mixing also produces 5–10% spillage and trowel-down waste that's already covered in this margin.
Does mortar ratio change for 12 inch blocks?
Slightly — 12 inch blocks have the same face dimensions and joint count as 8 inch, so per-block mortar volume is similar. The calculator assumes the NCMA 1 bag / 30 blocks rule, which is conservative for either size.
Looking for the general calculator?
Estimate cinder blocks and mortar bags for any CMU wall. Supports 8-inch and 12-inch blocks with adjustable waste percentage and automatic pallet estimation.
Open the Cinder Block Calculator: Blocks & Mortar →