Cinder Block Calculator
Estimate block quantity for a rectangular wall.
Calculate cinder block calculator from clear inputs
Cinder Block Calculator gives a focused worksheet for home & diy questions where a quick deterministic estimate is more useful than a spreadsheet. The cinder block calculator fields mirror the variables in its formula, and the output separates the main result from supporting values so you can sanity-check this calculation before reusing it.
A 30 by 6 foot wall with 0.889 square foot blocks and 10 percent waste needs 223 blocks.
Keep the estimate private in your browser
For Cinder Block Calculator, every calculation runs in your browser with no upload, account, cookie, live lookup, or server-side storage. The cinder block calculator result is best treated as a planning number because the real-world constraints behind this estimate can change the answer. Adjust the cinder block calculator assumptions and confirm important decisions against the relevant source of truth for that exact situation.
Frequently Asked Questions
What block face area should I enter?
A standard 8 × 8 × 16 inch concrete block covers about 0.889 sq ft of wall face including a 3/8 inch mortar joint. Use a different value for half blocks or other sizes.
How is the count calculated?
Wall length × height gives the area, which is divided by the block face area and increased by your waste percent, then rounded up. A 30 × 6 ft wall with 10% waste needs 223 blocks.
Does it subtract doors or windows?
No. Subtract openings from the wall area first by reducing the length or height, or work out the openings' square footage and take it off before entering.
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