✓ ASTM C90 Standard CMU Sizing
Cinder Block Wall Calculator
Estimate standard 8x8x16 concrete blocks, corner units, Type S mortar bags, and core grout volume.
Wall Dimensions & Core Fill Settings
Masonry Material Requirements
CMU Blocks Needed 142 8"×8"×16" Standard
Mortar Bags (70lb) 5 Bags Type S / Type N
Total Wall Surface Area: 120.0 sq ft
Corner Blocks Needed: 18 Blocks (9 courses)
Core Fill Grout Volume: 0.00 cu yds
Frequently Asked Questions
How many standard cinder blocks do I need per square foot of wall?
Standard CMU cinder blocks measure 8" high by 16" long (including a standard 3/8" mortar joint). This equals 1.125 blocks per square foot of wall area. A 100 sq ft wall requires approximately 113 blocks (or 118 with 5% waste).
How many bags of mortar do I need for 100 cinder blocks?
One 70-pound bag of Type S or Type N masonry mortar will lay approximately 30 to 35 standard 8x8x16 cinder blocks. For 100 blocks, you will need approximately 3 to 4 bags of mortar mix.
Should I fill cinder block cores with concrete or grout?
For retaining walls, structural foundations, and load-bearing walls, filling every 2nd or 3rd core (or all cores) with coarse grout reinforced with vertical #4 rebar provides high shear and lateral pressure resistance.