Concrete block calculator.
Type in your wall lengths and heights. Get the whole material list — block count, mortar bags, masonry sand, grout cubic yards and rebar — and download it as a proper Excel takeoff with live formulas.
| Wall | Length (ft) | Height (ft) | Openings SF | Net SF |
|---|
| Material | Qty | Unit | How it’s figured |
|---|
How the math works
Every factor in this calculator is a standard masonry rule of thumb. These are field averages — adjust them to your mix, joint size and reinforcing schedule. Every factor is visible in the Excel download so you can audit or change it:
- Net wall SF — length × height − openings SF, per wall.
- Block — net SF × 1.125 block per SF (standard for a nominal 8″×16″ face, any thickness) × (1 + waste), rounded up.
- Mortar (type S) — assumption: ≈3 bags per 100 block (about one 80-lb bag per 33 block). Wider block and bigger joints use more — adjust as needed.
- Masonry sand — assumption: ≈0.045 tons per mortar bag.
- Grout — cubic yards from a CY-per-100-SF table by block width and grouted-cell spacing. For 8″ block: all cells = 0.93, 16″ OC = 0.55, 24″ OC = 0.41, 32″ OC = 0.31, none = 0. The full table for 6″/8″/10″/12″ is in the Excel notes.
- Vertical rebar — bars per wall = length × 12 ÷ spacing + 1, each bar = wall height; total LF summed across walls. (At “every cell” spacing is 8″.)
- Horizontal bond-beam rebar (optional) — one course every 4′ of height: LF = length × roundup(height ÷ 4).
This is the easy 20%. The other 80% is on your drawings.
A length-based calculator prices the straight runs you already understand. What it can’t do is read a masonry set: the reinforcing schedule, the bond-beam and lintel details, the special shapes at corners and jambs, the grouted-cell pattern that changes by wall type. That’s the part of a masonry bid that leaks money — and it’s exactly what Pilars AI takeoff for masonry does from your actual plans: it reads every wall and detail and returns block, mortar, grout and reinforcing by type. $100 per trade, per plan.
Questions masons actually ask
How does the calculator count block?
Net wall SF (length × height − openings) × 1.125 block per SF — the standard factor for a nominal 8″×16″ face block of any thickness — plus your waste %, rounded up.
How much mortar and sand?
≈3 bags of type S mortar per 100 block (about one 80-lb bag per 33 block) and ≈0.045 tons of masonry sand per bag. Both are common field averages; adjust to your mix and joints.
How is grout calculated?
From a cubic-yards-per-100-SF table by block width and grouted-cell spacing. For 8″ block: all cells = 0.93, 24″ OC = 0.41, 32″ OC = 0.31, none = 0. Factors for 6″/8″/10″/12″ block are carried in the tool.
Can I download the takeoff as Excel?
Yes — one click exports a real .xlsx workbook with a Walls sheet and a Materials sheet. The cells carry live Excel formulas, so you can change lengths, waste, grout spacing or rebar spacing inside Excel and everything recalculates. There’s a blank reusable template too.
Is this as accurate as a real plan takeoff?
It’s a fast estimating tool built on standard masonry factors. It doesn’t read your reinforcing schedule, bond-beam details or special shapes — that’s what Pilars does from your actual drawings for $100 per trade.
Let Pilars take off your whole set.
Upload your plans. Pilars reads the reinforcing schedule, applies the grouted-cell pattern by wall type, catches bond beams and special shapes, and returns the full masonry takeoff — block, mortar, grout and rebar. $100 per trade.