Block & Mortar Calculator
Plan your block order and choose complete mortar mix or cement and sand mixed on site. Use the product and mix specification for your project.
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Stored on this device only. Anyone with a shared link can read its estimates. Don’t put addresses or personal details in labels. Concrete, concrete bags, gravel and blockwork share this list. Compatible demand is combined before purchasing rounding. Up to 20 items; long projects may need printing instead of sharing.
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Storage, sharing & privacy
No dimension inputs or project payloads are sent to analytics. This preview has no ads, analytics or account system. Shared estimates are encoded in the URL fragment, not the page path. Projects are stored in this browser’s local database. Browser clearing, eviction or device loss can remove them; keep a shared link or printed copy of important estimates. Clear project removes database estimates; retained older storage may still appear for explicit recovery.
Incoming shared projects open for review. They never replace a saved project automatically. Save an individual shared estimate to add it to your local project.
How blocks and mortar are estimated
Subtract non-overlapping doors and windows from each wall face. Divide the net area by the block’s coordinating face area, then apply your extra-block allowance. Nominal dimensions include a joint; specified dimensions need the joint added once.
Worked example: 10 × 8 ft wall
A nominal 16 × 8 in face covers 8/9 ft². The 80 ft² wall needs 90 installed block equivalents. With 5% extra, buy 95 individual blocks. A separate 10% mortar allowance gives 99 block equivalents for coverage. The QUIKRETE 1102 upper reference yield of 13 blocks per 80 lb bag gives 8 complete-mix bags.
Alternatively, the named masonry-cement recipe’s approximate coverage of 46 blocks per batch gives 99/46 batches: buy 3 × 70 lb binder bags and 11 × 50 lb sand bags. Sand demand comes from the fractional batches, not the 3 purchased cement bags. These alternatives are not added together.
For your own cement:sand recipe
Enter the specified loose-volume parts, a gauge size and either matching blocks-per-batch coverage or measured wet yield. Buying ingredients by mass also needs matching supplier density or mass-per-gauge calibration. A ratio alone does not establish wet yield, bag count or mortar strength. No universal wet-to-dry multiplier is assumed.
Practical limits and ordering guidance
Block sizes and mortar coverage are starting estimates. Check your supplier’s exact block dimensions, bedding requirements, product coverage and recipe before ordering. Coverage varies with joints, block type and site conditions.
For straight, rectangular, single-leaf mortared walls. This tool estimates quantities; it does not assess structural suitability or include grout, reinforcement, foundations, lintels, retaining-wall systems or an exact cutting schedule. Follow the specified mortar recipe, including lime where required. Areas and openings must not overlap; positions are not checked.