RightQty

Hardscape & masonry

Concrete block calculator

Estimate concrete masonry units from net wall face area and add a configurable planning allowance for mortar bags.

Masonry wall

Calculate concrete blocks and mortar

Measurement system
Add all door, window, and other openings together.
Default: QUIKRETE publishes up to 13 standard 8 × 8 × 16 in blocks per 80 lb Mason Mix bag; replace it with your product's yield.
Overage

Covers spillage, uneven depth, settling, and minor measurement differences.

Optional material costEnter your supplier's USD price

Material only; taxes, delivery, tools, reinforcement, and labor are excluded.

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Your material estimate

Concrete blocks

189blocks

Includes 5% overage and purchase-unit rounding where applicable.

Gross wall area
160 sq ft
Net area after openings
160 sq ft
Approx. mortar bags
15 bags

Example estimate: default sample values are shown. Update the measurements and select Calculate before using or copying this list.

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Shopping list

  • Concrete masonry unitsNet wall area plus 5% overage.189 blocks
  • Mortar mixPlanning allowance at 13 blocks per bag. The default references an 80 lb QUIKRETE Mason Mix bag; verify the selected product.15 bags
Calculation assumptions
  • Nominal block face dimensions include the intended mortar-joint module.
  • The entered opening area is subtracted once from gross wall area.
  • Mortar is estimated at 13 blocks per bag; the default of 13 references the published maximum for one 80 lb QUIKRETE Mason Mix bag laying standard 8 × 8 × 16 in blocks.
  • Joint profile, block geometry, workmanship, and the selected mortar product can change actual coverage.
  • Bond beams, lintels, grout, reinforcement, corners, and specialty units are outside this quantity estimate.

Net-area math

How concrete masonry units are estimated

1

Net wall area

Subtract total openings from wall length × wall height.

2

Nominal module

Divide net area by nominal block length × height, including the joint module.

3

Purchase allowance

Add block waste and divide the order count by entered mortar coverage.

Planning boundary

Special units and grout are separate

Measure the full wall face, then total door, window, and other openings separately. Enter the nominal installed block module—including the intended mortar joint—not only the concrete unit's physical dimensions.

The editable default of 13 blocks per mortar bag references QUIKRETE's published maximum for one 80 lb Mason Mix bag laying standard 8 × 8 × 16 in blocks. Replace it with the yield for the product and joint you will use.

Corner blocks, bond beams, lintels, cut units, grout, reinforcement, flashing, and control joints depend on the wall design. Mortar coverage varies with joint profile, block geometry, workmanship, and product yield.