Enter your Number of Blocks, Block Size, Mortar Type, Mortar Joint Thickness, and Waste Factor into the Block Mortar Calculator to find exactly how much mortar your project needs — including 60 lb and 80 lb Pre-Mixed Bags, Total Mortar Volume, and raw materials like Portland Cement and Hydrated Lime.
60 lb Pre-Mixed Bags
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80 lb Pre-Mixed Bags
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Total Mortar Volume
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Portland Cement
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Hydrated Lime
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Sand
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For 100 standard 8"×8"×16" blocks with 3/8" joints, you'll typically need about 12-15 bags of 60 lb pre-mixed mortar, depending on the mortar type and waste factor.
Type O is for interior/low-load applications, Type N is general purpose for most projects, Type S is for below-grade and high-strength needs, and Type M is for high-load structural applications.
Both will work for your project. 60 lb bags are easier to handle and mix, while 80 lb bags require fewer bags overall but are heavier to work with. Choose based on your physical capabilities and preference.
Larger blocks require more mortar per unit due to increased bed joint area and potentially thicker head joints. This calculator accounts for different standard block sizes automatically.
A 10-15% waste factor is typical for mortar projects to account for spillage, mixing waste, and application loss. Use 10% for experienced masons and 15% for DIY projects.
Yes, you can mix mortar from raw materials (cement, lime, sand). This calculator provides the quantities needed for both pre-mixed bags and individual components for on-site mixing.
Standard mortar joint thickness for concrete blocks is typically 3/8 inch, though 1/4 inch and 1/2 inch joints are also used depending on the application and aesthetic preferences.
You can estimate by calculating the number of blocks first: divide wall area by the face area of one block, then use this calculator. Standard 8"×16" face blocks cover approximately 0.89 square feet each.