Wall 1
Length: — ft · Height: — ft · Thickness: — in · Opening length: — ft · Opening height: — ft · Number of openings: — qty
Wall volume estimator
Concrete Wall Calculator
Calculate a concrete wall and subtract repeated rectangular openings when needed.
Project
Subtract openings only if you measured all three
Formula
Gross wall minus the openings you enter
Net wall volume = length × height × thickness − opening length × opening height × thickness × opening count. Leave the opening fields blank for a solid wall.
Common mistake
Subtracting a door you have not measured
An opening reduces the order only when you enter its length, height, and count. Guessing a doorway, or subtracting rebar and small sleeves, makes the wall look shorter than the pour.
Worked quantities
Walls with and without openings
Compare the solid 20 × 8 ft wall with the same wall after one 3 × 7 ft opening. The difference is the concrete you should not order twice.
| Wall | Openings | Measured yd³ | Order yd³ |
|---|---|---|---|
| 20 × 8 ft, 8 in | None | 3.95 | 4.50 |
| 20 × 8 ft, 8 in, one opening | One 3 × 7 ft | 3.43 | 4.00 |
| 30 × 4 ft stem, 6 in | None | 2.22 | 2.50 |
| 40 × 8 ft, 10 in, two openings | Two 3 × 7 ft | 8.58 | 9.50 |
| 12 × 3 ft, 8 in | None | 0.89 | 1.00 |
Field check
Subtract only real openings
Use opening dimensions and count for doors, windows, or repeated voids that will not be filled. Do not subtract embedded reinforcement or small penetrations that do not materially change the order.
Field check
Separate walls by thickness
A foundation wall, stem wall, and return wall can share a job, but each distinct thickness or height should be entered as its own section. This preserves an auditable volume for every run.
Field check
Check units before entering height
In US mode the form may mix feet for overall dimensions with inches for thickness. Read each field label instead of assuming every number uses the same unit.
Questions
What the wall calculator answers
Can I subtract doors or openings?
Yes. Enter opening length, height, and count.
Can walls have different thicknesses?
Add another section for each thickness.
Does this calculate formwork or reinforcement?
No. The result covers concrete quantity and cost only.
Next step
Price the order after the openings are subtracted
Bag yields follow the cited manufacturer data. See sources and review dates.