Wall faces · openings · blocks and pallets

Concrete Block Calculator

Estimate CMU blocks for wall faces after deducting doors and windows. Use nominal modules or actual block dimensions with mortar joints, then plan spare blocks, pallets, mortar bags, and material cost.

Calculate Concrete Blocks How to Measure

Worked example

16 × 8 ft wall · 16 × 8 in module144 blocks

Wall face area: 128 sq ft
With 5% block waste: 152 whole blocks
If ordering full 90-block pallets: 180 blocks · 2 pallets

Illustrative example. Measurements, allowances, product details, and prices are not prefilled from this example.

Your measurements

Measure wall faces and openings

Add wall faces that do not overlap, then subtract door and window openings.

For rectangles, enter wall length and height. Subtract doors and windows once, without overlapping openings. Use one block face size per calculation.

Section 1

Section name Optional

Include or exclude?

Shape

Measurement unitsSwitching units converts existing measurements. Decimal feet are also accepted.

Length

FeetInches

Wall height

FeetInches

Measure inside edges for floors. For walls, use wall width and height.

Extra material allowance Optional

Leave at 0 for measured area only. For materials, choose an allowance for cuts and waste using your product’s instructions. Applied after exclusions.

Block size and purchasing

How are block dimensions specified?Starts at the common 16 × 8 in nominal face. Switching modes preserves the module by adding or subtracting the entered joint.

Block and joint units

Block face length

Horizontal face size; wall thickness does not change area-based block count.

Block face height

Nominal dimensions already include a mortar joint. Actual dimensions require the separate joint below.

Blocks per pallet

blocks

Optional supplier pallet size; enter a whole number.

Price per block

$/block

Optional. Cost uses the purchase count, including whole-pallet rounding when selected.

Blocks laid per mortar bag

blocks/bag

Optional product coverage for your block size, mortar joint and laying method. No universal coverage is assumed.

Mortar extra allowance

Starts at 0%. Applied to installed block equivalents, independently of surplus blocks and pallets.

Price per mortar bag

$/bag

Optional; requires blocks laid per mortar bag.

Total delivery fee

Optional total fee for this order.

Order whole pallets

Your result

Know the area before you shop

Enter your dimensions to see net square footage, metric conversions, and a section-by-section breakdown here.

Suggest an improvement

Measure first

Use the wall face and the correct block module.

Enter wall length and height, then subtract non-overlapping door and window openings once. Keep one block face size per calculation. Triangles can represent gable faces. A block’s thickness affects wall construction but does not change coverage when its face dimensions stay the same.

Net wall area

Sum included wall faces and deduct openings. Do not deduct a door or window again when it is already excluded from your measurements.

Module coverage

Nominal length × nominal height includes mortar joints. For actual face dimensions, use (length + joint) × (height + joint). Convert the resulting face coverage to square feet.

Block purchase

Net wall area ÷ module coverage gives full-block equivalents. Apply block waste and round up once. If buying full pallets, round the block requirement up to the pallet size.

Mortar and cost

Installed equivalents × mortar allowance ÷ supplier blocks-per-bag coverage gives whole mortar bags. Spare blocks and pallet surplus do not increase installed mortar. Costs use the actual purchase counts.

From measurement to purchase

A 16 × 8 ft wall has 128 sq ft of face area. A nominal 16 × 8 in module covers 0.888889 sq ft, giving 144 full-block equivalents. Adding 5% block waste requires 152 whole blocks. At 90 blocks per pallet, choosing whole pallets increases the order to 180 blocks. Deduct openings before applying waste.

FAQ

Concrete block planning questions

Do I enter nominal or actual block dimensions?

Choose the matching mode. The starting 16 × 8 in face is nominal and includes a mortar joint. A 15.625 × 7.625 in actual face plus a 0.375 in joint gives the same module. Do not add mortar again to nominal dimensions. Custom metric blocks can use their own dimensions.

Do 6-inch and 8-inch blocks have different counts?

Not if their face length and height are the same. Their wall thickness, weight, mortar consumption, grout capacity, and structural properties can differ. This tool does not infer those properties from face size.

How are openings and cuts handled?

Openings are subtracted by face area. The count is a full-block-equivalent estimate; actual courses, bond pattern, reusable offcuts, corners, half units, lintels, and specialty blocks need a separate layout takeoff.

Is mortar consumption assumed?

No. Enter the blocks laid per bag from your mortar product or supplier for your block size, joint and bedding method. Mortar allowance is separate from block waste.

What happens when I enter blocks per pallet?

The result shows the rounded-up pallet equivalent. Enable Order whole pallets to increase purchased blocks to that quantity; otherwise costs use the required whole-block count.

Does this design a load-bearing or retaining wall?

No. This estimates material quantities only. Foundation design, reinforcement, grout, structural capacity, lintels, drainage, and local approvals require project-specific design. Segmental retaining-wall systems need their own product takeoff.

What is included in total cost?

Purchased blocks, mortar only when coverage and mortar bag price are entered, and the entered delivery fee. Unpriced materials, grout, reinforcement, labor, tax, and other fees are excluded.

References

Check product specifications before ordering.

Concrete Masonry & Hardscapes Association

Modular layout guidance distinguishing face modules from physical block dimensions.

View reference ↗

Cemex block calculator

Manufacturer block quantity and masonry material planning reference.