How to use this calculator
- Enter Wall length in ft.
- Enter Wall height in ft.
- Press Calculate. The highlighted row is your order quantity; the note beneath it translates the number into real-world terms.
Formula & constants
A standard 8×8×16 block occupies 0.89 sq ft of wall face: wall area × 1.125 = blocks, +5% waste. Figure one 70 lb mortar bag per 30–35 blocks. Every default in the fields above is editable — when your supplier’s spec sheet lists a different density, coverage rate or price, enter that number instead. The waste and compaction allowances follow common trade practice; see our methodology page for the derivation of each formula and the standards it references.
Where this fits in the project
Concrete work starts below grade: excavation, then a compacted gravel base for drainage, formwork, rebar where the slab spec requires it, then the pour. Order by cubic yard and round up — a short load fee costs more than surplus material.
How this connects to your project
No quantity stands alone — each material in the chain depends on the ones around it. These are the planning steps that pair with the concrete block calculator:
- Concrete Calculator — CMU block vs poured concrete wall comparison.
- Retaining Wall Calculator — Both use concrete blocks for wall construction.
- Rebar Calculator — Block walls need vertical rebar and grout.
- Concrete Footing Calculator — Block walls require concrete footings.
Frequently asked questions
How many blocks per square foot of wall?
1.125 standard blocks per sq ft — each covers 0.89 sq ft of face.
Do block cores need filling?
Cores with rebar get grouted per the engineering; bond beams and cells below grade commonly fill too.
Last verified: — prices reflect current national averages. See our methodology.
Estimates are for planning. Material densities, coverage rates and prices vary by region and supplier — confirm final quantities before ordering, and check local code where structural or electrical work is involved.