Concrete Wall Calculator
Estimate concrete, formwork and rebar for poured foundation walls, stem walls, basement walls and freestanding concrete walls. Subtract window and door openings for an accurate order.
Concrete Wall Calculator: Poured Foundation Wall Volume & Cost
Poured concrete walls are used for basement and crawlspace foundations, stem walls on slab-on-grade homes, garage frost walls, and freestanding site walls. Estimating them accurately matters more than for most pours because wall jobs are large — a modest basement can easily need 25–40 cubic yards — and running short means a cold joint partway up a structural wall while you wait for another truck.
Wall volume is length × height × thickness, minus any openings for windows, doors or beam pockets. Thickness drives the total more than anything else: going from an 8" to a 10" wall adds 25% more concrete. Most residential foundation walls are 8" thick, with 10"–12" walls used for deeper basements, taller unbalanced backfill or where the plans call for them. Stem walls and short frost walls on slab homes are often 6"–8".
Formwork is the other half of the estimate. Every square foot of wall has two faces that need forms, so a 120 ft × 8 ft wall needs about 1,920 sq ft of form surface. Contractors use rented or owned aluminum panel systems, while DIY and small jobs usually use site-built plywood forms. Insulated concrete forms (ICF) stay in place permanently and change the math — use the core thickness of the ICF block as your wall thickness.
In 2026 the installed cost of poured foundation walls in the US typically runs about $20–$35 per square foot of wall face, including forming, rebar, concrete and stripping, with higher prices in major metros and for walls over 9 ft tall. Ready-mix alone averages about $150–$185 per cubic yard, and most wall pours need a concrete pump at roughly $500–$1,200 per day unless the truck chute can reach every section.
Reinforcement varies widely by region and code. Some plain concrete walls with low backfill need little or no vertical steel under the IRC prescriptive tables, while taller basement walls, high-seismic areas and walls with unbalanced fill heights over about 4–6 ft need vertical #4 or #5 bars at 12"–48" on center plus horizontal bars near the top and bottom. Always follow your plans or the IRC Section R404 tables for your wall height, thickness and soil type.
Windows, doors, beam pockets
How to Use This Calculator
Understanding Your Result
The ready-mix figure is what to tell your supplier, rounded up to a quarter yard and including 10% waste. On large wall pours, many contractors order slightly under and call the final few yards once they see how far the load goes — but only if the plant can deliver quickly.
Key Formulas
Wall Volume
Length and height in feet, openings in square feet. Divide by 27 for cubic yards.
Form Area
Both faces of the wall need forms. A 4 × 8 sheet of plywood covers 32 sq ft.
Wall Rebar
Vertical footage = bars × height. Horizontal footage = rows × length × 1.10 for laps.
Worked Example
A 30 × 30 ft garage with 120 ft of 8 ft tall, 8" thick poured walls, 24 sq ft of window openings, and #4 bars at 24" OC each way.
- 1Gross wall area = 120 × 8 = 960 sq ft; net = 960 – 24 = 936 sq ft
- 2Volume = 936 × (8 ÷ 12) = 624 cu ft = 23.1 cu yd
- 3Add 10% waste = 686.4 cu ft = 25.4 cu yd → order 25.5 cu yd
- 4Form area = 960 × 2 = 1,920 sq ft
- 5Vertical bars = 120 ÷ 2 + 1 = 61 bars × 8 ft = 488 ft
- 6Horizontal rows = 8 ÷ 2 + 1 = 5 rows × 120 ft × 1.10 = 660 ft
- 7Total rebar = 1,148 ft → 58 × 20 ft sticks (about 767 lb)
Order 25.5 cu yd of ready-mix (about $3,800–$4,700 at $150–$185/yd, plus pump), 58 sticks of #4 rebar, and forms for 1,920 sq ft of wall face.
Assumptions Behind This Estimate
- Thickness options are nominal (6", 8", 10", 12")
- 10% waste for form bulge, spillage and over-pour
- Openings subtract concrete volume but not form area (bucks and blockouts are still needed)
- Rebar estimate uses #4 bars (0.668 lb/ft) at your chosen spacing with 10% lap on horizontal runs
- Does not include the footing, pilasters, brick ledges or slab — estimate those separately
Concrete per 10 Linear Feet of Wall
| Wall Height | 6" Thick | 8" Thick | 10" Thick | 12" Thick |
|---|---|---|---|---|
| 2 ft (stem wall) | 0.37 | 0.49 | 0.62 | 0.74 |
| 4 ft (frost wall) | 0.74 | 0.99 | 1.23 | 1.48 |
| 8 ft (basement) | 1.48 | 1.98 | 2.47 | 2.96 |
| 9 ft (basement) | 1.67 | 2.22 | 2.78 | 3.33 |
| 10 ft (basement) | 1.85 | 2.47 | 3.09 | 3.70 |
Multiply by your total length ÷ 10, then add 10% waste.
Before You Buy: Practical Advice
- Pour in 2–3 ft lifts around the whole wall rather than filling one section to the top, so form pressure stays even.
- Consolidate each lift with a concrete vibrator to avoid honeycombing, especially around rebar and window bucks.
- Order a mix suited to walls (often 3,000–4,000 psi with a 4–5" slump) and ask about a pump mix if pumping.
- Install anchor bolts along the top of the wall immediately after screeding, at the spacing your code requires (commonly 6 ft OC and within 12" of corners).
- Damp-proof or waterproof the exterior of basement walls before backfilling, and do not backfill until the floor framing is in place or the wall is braced.
Frequently Asked Questions
How do I calculate concrete for a wall?
Multiply length × height in feet to get wall area, subtract openings, then multiply by thickness in feet. An 8" wall is 0.667 ft thick. For example, 120 ft × 8 ft = 960 sq ft, minus 24 sq ft of windows = 936 sq ft, × 0.667 = 624 cu ft = 23.1 cu yd. Add 10% for waste to get 25.4 cu yd.
How thick should a poured concrete foundation wall be?
Most residential foundation walls are 8" thick. Walls are often 10" or 12" when they are taller than about 8–9 ft, retain more backfill, or support heavy masonry above. Short stem walls on slab homes may be 6". The IRC Section R404.1 tables set minimum thickness and reinforcement based on wall height, backfill height and soil class.
How many yards of concrete for a basement?
A 30 × 40 ft basement with 140 ft of 8 ft high × 8" walls needs about 140 × 8 × 0.667 = 747 cu ft, or 27.7 cu yd, before waste. With 10% extra that is about 30.5 cu yd for the walls alone. Footings and the basement slab are separate pours that add more.
How much does a poured concrete wall cost per square foot?
Installed by a foundation contractor, expect roughly $20–$35 per square foot of wall face in 2026, depending on height, thickness, reinforcement, access and region. That works out to about $160–$280 per linear foot for an 8 ft wall. DIY material cost is much lower but forms, a pump and vibrator rental add up quickly.
Can I use bagged concrete for a wall?
Only for very small walls, such as a short garden wall or a single step. Above about 1–1.5 cubic yards, mixing enough bags fast enough to avoid cold joints is unrealistic. A cubic yard is 45 bags of 80 lb mix. For anything foundation-sized, order ready-mix.
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