Concrete Block (CMU) Calculator
Plan a block wall: blocks for the face area (openings deducted), bags of mortar, grout for fully or partially grouted cells, and mason hours.
Concrete Block (CMU) Calculator — ConcreteNear.com
| Wall face area | 160 ft² |
| 80-lb mortar bags (≈13 blocks per bag) | 15 |
| Grout (incl. 10% extra) | 0.31 yd³ |
| Mason hours | 12 hr |
| Courses (8 in each) | 6 |
Cost estimate U.S. average prices
| Concrete block 189 block × $2.25 | $425.25 |
| 80-lb mortar mix 15 bag × $9.00 | $135.00 |
| Grout 0.5 yd³ × $180.00 | $90.00 |
| Mason labor 12 hr × $28.87 × 2 | $692.88 |
| Helper / laborer 12 hr × $25.02 × 2 | $600.48 |
| Estimated total | $1,944 |
- Grout the vertical cells that hold rebar; bond beams at the top need grout too.
- Lay the first course in a full mortar bed on a level footing.
| Inputs | |
| Wall length | 40 ft |
| Wall height | 4 ft |
| Openings to deduct | 0 ft² |
| Block thickness (nominal) | 8 in |
| Grouted cells | Every 48 in on center |
| Extra blocks for breakage & cuts | 5% |
| Blocks laid per mason-hour | 15 |
Planning estimate only — confirm with your supplier or contractor.
Prices used — edit any price to match your local quote
| Item | Unit price | Basis & source |
|---|---|---|
| 8×8×16 concrete block (CMU) per block | starting estimate Starting estimate. Price varies by block type and yard. | |
| 80-lb bag of mortar mix per bag | starting estimate Starting estimate for a retail shelf price. | |
| Masonry grout (ready-mix) per yd³ | starting estimate Starting estimate; usually priced a little above structural ready-mix. | |
| Cement mason / finisher wage per hr | public source BLS Occupational Employment and Wage Statistics, May 2025, 47-2051 mean hourly wage (May 2025) — Worker wage, not a contractor's billed rate. The labor markup below converts wage to billed cost. | |
| Construction laborer / flagger wage per hr | public source BLS OEWS May 2025, 47-2061 Construction Laborers mean hourly wage (flaggers are classified here) (May 2025) | |
| Labor markup (wage → billed rate) per × | starting estimate Starting estimate covering payroll taxes, insurance, benefits, overhead and profit. Many contractors land between 1.6× and 2.5×. |
How to use this calculator
- Enter wall length and height and subtract doors and windows.
- Pick block width (8 in is standard for walls).
- Choose how often vertical cells are grouted (every cell, or e.g. every 48 in where the rebar is).
- Set mason output to see labor hours.
Formulas
Blocks = (length × height − openings) × 1.125 per ft² (8×16 in face) × (1 + breakage %)Mortar: about 13 blocks per 80-lb bag of mortar mixGrout yd³ ≈ blocks × cell volume × fraction of cells grouted ÷ 27 × 1.1
Questions
How many blocks are in a square foot?
A standard 8 × 16 in block face is 0.889 ft², so 1.125 blocks per square foot of wall.
How many blocks per bag of mortar?
A QUIKRETE 80-lb bag of Mortar Mix lays about 13 standard blocks.
How much grout does a block wall take?
A fully grouted 8 in wall takes about 0.25 ft³ per block — roughly 1 yd³ per 100 ft² of wall. Partial grouting takes much less.
Sources & assumptions
Prices checked 2026-11-10. State pricing multiplies national figures by the U.S. Bureau of Economic Analysis regional price parities (goods for materials, services for labor and services). RPPs compare general consumer price levels (U.S. = 100). They are not construction-specific; we use RPP Goods for materials and RPP Services: Other (excludes rents) for labor and services.
- Cement mason / finisher wage — BLS Occupational Employment and Wage Statistics, May 2025, 47-2051 mean hourly wage (May 2025). Worker wage, not a contractor's billed rate. The labor markup below converts wage to billed cost.
- Construction laborer / flagger wage — BLS OEWS May 2025, 47-2061 Construction Laborers mean hourly wage (flaggers are classified here) (May 2025)
Starting estimates No public price series was found for: 8×8×16 concrete block (CMU); 80-lb bag of mortar mix; Masonry grout (ready-mix); Labor markup (wage → billed rate). These defaults are editable placeholders — replace them with a local quote.
Results are planning estimates, not quotes or engineering advice. Codes, specifications and your supplier's numbers govern.
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