Masonry & Brickwork
Concrete Block / CMU Calculator
Calculates concrete masonry units (CMU) for walls and foundations
Updated April 28, 2026 · Live
What this tool does
Calculates concrete masonry units (CMU) for walls and foundations. 8x8x16 standard.
Formula Used
People also use
How the concrete block / cmu calculator works
Calculates concrete masonry units (CMU) for walls and foundations. 8x8x16 standard. The calculator takes your dimensions and supplier rates, applies a standard US construction formula, and returns a quantity with an indicative cost. Every figure is an estimate — site conditions always move the final number.
Typical US masonry and brickwork wastage
Brick wastage is 5% on running bond, 10% on Flemish or other patterned bonds. CMU (block) wastage at 5–7% is adequate for straight walling. Our defaults reflect common US trade allowances — adjust upwards for non-standard geometry, downwards if your experience says so.
What this tool does not do
It does not replace a professional quote, factor regional pricing, assess structural adequacy, or confirm building code compliance. Those remain the responsibility of a suitably qualified designer, engineer, or your local building official.
On-site considerations for concrete block / cmu
Wet weather slows mortar curing and can wash out joints — protect fresh work with poly sheeting. Don't lay below 40°F without cold-weather admixtures or a heated enclosure.
Codes and compliance
Loadbearing masonry is governed by ACI 530/TMS 402 and the IRC/IBC. Brick ties (corrosion-resistant), flashing, and weeps are code requirements, not optional. When in doubt, file a pre-application question with your local building department — early clarity is cheaper than a corrective inspection.
Before you order
Order brick by the strap (not the broken pallet) and keep it dry. Wet brick will leach efflorescence to the face and leave permanent staining. Always cross-check the calculator's output against a supplier quote — ask for exact product specifications (grade, finish, batch number) and confirm delivery timescales against your programme.
Adjusting the defaults
Every input in this calculator is editable. Enter your own dimensions, supplier prices, and wastage allowance — the output recalculates instantly. If the defaults feel off for your region or project type, your own numbers always override them.
Using this concrete block / cmu calculator alongside other BuildMetricLab tools
This calculator works best as part of a planning workflow. Pair the quantity with our project contingency, labor-hours, and material-cost calculators to build a complete estimate before you pick up the phone to a supplier. All BuildMetricLab tools run entirely in your browser — no sign-up, no data sent anywhere, and every formula is shown on-page so you can audit the math.
Sources & methodology
Calculates concrete masonry units (CMU) for walls and foundations. 8x8x16 standard. Uses US construction defaults for wastage and density. Prices are illustrative April 2026 values and vary by region; change them to match your supplier quote.
Frequently asked questions
Are concrete block / cmu calculator results accurate enough to order materials?
Use them as a starting estimate only. Always verify the final quantity with your supplier or contractor before ordering — site conditions, wastage and cut-offs all affect the true figure.
What wastage percentage should I use?
The calculator defaults to the typical US trade allowance for masonry & brickwork. Increase it for complex cuts, awkward shapes, or first-time DIY. Reducing the wastage below the default is not recommended.
Does this replace professional advice?
No. This tool is a planning estimator. For work that affects structure, building code compliance, gas, electrical, plumbing, or drainage to a public sewer, consult a licensed contractor or design professional.
Can I change the unit prices?
Yes — every price field is editable. Plug in your supplier's quote to get a total that matches your project.
Related tools
Calculators from other categories that planners often reach for next.