Concrete Block & Wall Calculator: Fill & Poured Walls
This concrete block and wall calculator estimates how much concrete you need to fill CMU block cells or pour a solid wall, based on your wall dimensions. Knowing the fill volume in advance keeps grout pours and foundation walls on budget and prevents ordering the wrong load size.
Estimated concrete
Estimates only. Add ~5–10% for waste. Bag yields: 40 lb ≈ 0.30, 60 lb ≈ 0.45, 80 lb ≈ 0.60 cu ft. Concrete ≈ 150 lb per cu ft.
How the Concrete Block & Wall Calculator works
- 1
Enter your dimensions
Type the length, width and thickness of your slab, footing or pad and choose your units, feet, inches or meters.
- 2
Get instant volume
See the result in cubic yards, cubic feet and cubic meters, plus weight, the moment you type, no page reloads.
- 3
Buy the right amount
We convert volume into the exact number of 40, 60 and 80 lb bags, truck loads and cost so you order without waste or shortfalls.
The formula
Poured wall ft3 = Length_ft x Height_ft x (Thickness_in / 12); Blocks = wall_area_ft2 / 0.888
- ·Length_ft = wall length (feet)
- ·Height_ft = wall height (feet)
- ·Thickness_in = wall or block thickness (inches)
- ·wall_area_ft2 = Length_ft x Height_ft
- ·0.888 = face area (ft2) of one 8 x 16 in block
For a poured wall the tool returns cubic feet and yards; for a block wall it returns block count from the wall face area. A standard 8 x 16 in block covers 0.888 ft2 of wall face including a mortar joint.
Worked examples
Example 1: Poured wall, 20 ft long x 8 ft tall x 8 in thick
- Face area = 20 x 8 = 160 ft2
- Thickness = 8 / 12 = 0.667 ft
- Volume = 160 x 0.667 = 106.67 ft3
- Yards = 106.67 / 27 = 3.95 yd3
Result: About 3.95 cubic yards of concrete
Example 2: Block count for a 30 ft x 8 ft wall
- Face area = 30 x 8 = 240 ft2
- Blocks = 240 / 0.888
- = 270.3, round up to 271
Result: About 271 standard 8 x 16 in blocks
Concrete calculators by project type
Concrete bag yield & coverage
How much mixed concrete a standard bag yields, and how far a cubic yard goes at common slab depths.
| Bag size | Yield (cu ft) | Bags per cubic yard |
|---|---|---|
| 40 lb | 0.30 | 90 |
| 60 lb | 0.45 | 60 |
| 80 lb | 0.60 | 45 |
- 40 lb
- 60 lb
- 80 lb
Related guides
Concrete block & wall calculator FAQs
How much concrete does it take to fill a standard 8-inch block?
A standard 8×8×16 CMU has two cells that hold roughly 0.19–0.22 ft³ of concrete or grout combined when fully filled. That works out to about 120–140 blocks filled per cubic yard, depending on the block's exact core size.
Do I need to fill every cell in a block wall?
Not always, many walls only grout the cells that contain vertical rebar plus the bond beam, which uses far less concrete than a fully filled wall. Check your engineered plans or local code for the required fill spacing.
How do I calculate concrete for a poured wall instead of block?
For a solid poured wall, multiply length × height × thickness to get cubic feet, then divide by 27 for cubic yards. An 8-inch-thick wall uses 0.667 ft of thickness in that formula.
How many yards of concrete for a poured basement wall?
A 30 ft long, 8 ft tall, 8-inch-thick poured wall is 30 × 8 × 0.667 = 160 ft³, or about 5.9 cubic yards. Add 5–10% for waste and form movement.
What mix should I use for filling block cells?
Cell fill is usually a fluid grout or a pea-gravel concrete so it flows fully around rebar and into every core. A standard 1:2:3 mix works for poured walls, while grout uses finer aggregate to avoid bridging.
How much does it cost to fill a block wall with concrete?
Fill concrete costs the same per yard as any ready-mix, roughly $125–$165 delivered, so the total depends on how many cells you grout. Filling only rebar cells can cut the concrete volume by more than half versus a fully grouted wall.
How many blocks do I need per square foot of wall?
A standard 8 x 16 in block covers 0.888 square feet of wall face, so you need about 1.125 blocks per square foot. Multiply your wall face area by 1.125, or divide the area by 0.888. A 100 square foot wall takes roughly 113 blocks.
How much concrete does it take to fill a block wall?
Fully grouting standard 8-inch block takes roughly 0.5 to 0.6 cubic feet per block once you account for the hollow cells. A 100-block wall therefore needs about 50 to 60 cubic feet, or close to 2 cubic yards. Filling only reinforced cells uses far less.
What is the difference between filling block and pouring a solid wall?
Block fill grouts the hollow cores of a masonry wall for added strength, while a poured wall is solid concrete cast in forms. The calculator handles both: block mode counts units, poured mode returns cubic yards. Poured walls need far more concrete for the same dimensions.
How do I calculate concrete for a poured wall in yards?
Multiply length by height by thickness in feet to get cubic feet, then divide by 27. A 24 x 8 ft wall at 10 inches thick is 24 x 8 x 0.833 = 160 ft3, or 5.93 cubic yards. Add a waste margin before ordering.
Do I subtract door and window openings from a block wall?
Yes, subtract the face area of any openings before dividing by 0.888, otherwise you will over-order. For a 240 ft2 wall with a 3 x 7 ft door (21 ft2), use 219 ft2, which is about 247 blocks. For small openings many builders skip the subtraction as built-in waste.
How thick is a standard concrete block?
Nominal blocks come in 4, 6, 8, 10, and 12-inch thicknesses, with 8-inch being the most common for walls. Actual dimensions are 3/8 inch smaller to allow for mortar joints, so an 8-inch block is really 7.625 inches. Use the nominal thickness when estimating fill volume.
What mix strength should I use to fill block cells?
Cell fill typically uses a fluid grout or a pea-gravel concrete around 2000 to 3000 PSI so it flows into the cores. It should be wet enough to consolidate without voids but not so soupy it segregates. Add rebar in filled cells for structural walls.