Primary material
62 bags
80 lb concrete mix
Use the calculated bag count as your buying starting point, then verify yield and pallet limits with the store.
Concrete wall calculator
Concrete wall calculator for poured walls and wall stems.
Enter wall length, height, thickness, and waste allowance to estimate cubic yards, bag count, and rough material cost.
20 ft x 2 ft x 8 in
1.09 yd³
49 bags at 80 lb
Formula
L x H x T
Thickness converted to feet
Best for
Walls
Poured walls and wall stems
Quick reference
Concrete per 10 feet of poured wall
Cubic yards and 80 lb bags for every 10 ft of wall length, including the default 10% waste.
| Wall section | Yards per 10 ft | 80 lb bags per 10 ft |
|---|---|---|
| 2 ft high x 6 in thick | 0.41 yd³ | 19 |
| 3 ft high x 8 in thick | 0.81 yd³ | 37 |
| 4 ft high x 8 in thick | 1.09 yd³ | 49 |
| 8 ft high x 8 in thick | 2.17 yd³ | 98 |
| 8 ft high x 10 in thick | 2.72 yd³ | 123 |
Measure thickness between the form faces. Walls over about 1 yd³ are usually ordered as ready-mix.
Quick wall answers
Common poured wall sections
20 ft short wall
20 ft x 2 ft x 8 in
1.09 yd³
49 bags at 80 lb with default 10% waste
40 ft foundation wall
40 ft x 4 ft x 8 in
4.35 yd³
196 bags at 80 lb with default 10% waste
Retaining wall stem
30 ft x 3 ft x 10 in
3.06 yd³
138 bags at 80 lb with default 10% waste
Openings and forms
This page estimates a solid rectangular wall. For window openings, pilasters, keys, or stepped wall sections, calculate each piece separately.
Shopping list
Ready to price and order
Use the calculated quantities as a starting cart, then compare store availability, delivery fees, pallet limits, and local ready-mix minimums before buying.
Large pours
Ready-mix quote check
For high bag counts, compare the bagged route against local ready-mix minimums, delivery, access, and unload time.
Optional base
Gravel base
Base depth is project-specific. Estimate it separately before adding bags or bulk gravel to the order.
Optional forms
Forms and stakes
Plan lumber, stakes, screws, release, and bracing around the perimeter and any step-downs or curves.
Store buttons open retailer search results for now. Confirm exact product yield, pickup, delivery, and pallet rules before ordering.
Formula shown
How the wall calculation works
1. Convert thickness to feet
thickness ft = thickness in / 12
2. Calculate wall volume
cubic feet = length ft x height ft x thickness ft
3. Add waste and estimate bags
bags = ceil(cubic feet x (1 + waste) / bag yield)
Wall edge cases
Tall walls, retaining walls, basement walls, and walls with soil pressure need more than a volume estimate. Reinforcement, form bracing, drainage, and footing design should be reviewed before pouring.
Sources
- Quikrete product yields — bagged concrete mix yield references
- Sakrete bagged concrete references — common bag sizes and concrete mix guidance
- ConcreteNetwork concrete price guide — ready-mix and installed concrete cost context
Sources checked
Checked against
Bag yields checked against Quikrete and Sakrete product specs; price ranges against published concrete cost guides.
How we check our numbersLast updated: June 20, 2026
Estimate only.
This calculator is not a quote. Verify product yield, price, delivery minimums, and local conditions with your supplier or contractor before buying materials.
Related calculators
Other concrete tools
Concrete footing Use for strip footings and pad footings below walls or piers. Concrete slab Use for patios, shed pads, sidewalks, and driveway panels. Concrete calculators Browse all concrete shapes and cost tools. Concrete block (CMU) Building a block wall instead of poured? Estimate blocks and mortar.
FAQ
Concrete wall questions
Answers for wall volume, openings, bags vs ready-mix, and structural limitations.
How do I calculate concrete for a poured wall? + -
Multiply wall length in feet by wall height in feet by wall thickness in feet. This calculator lets you enter thickness in inches, converts it to feet, then adds the entered waste allowance.
How much concrete is needed for a 20 ft wall? + -
For a 20 ft long, 2 ft high, 8 inch thick wall, the calculator estimates about 1.09 cubic yards with the default 10% waste allowance, or about 49 bags of 80 lb concrete mix. You can edit waste for your formwork and jobsite.
Can I subtract window or door openings? + -
This first version estimates a solid rectangular wall. For large openings, estimate the opening volume separately and subtract it, or use a project-specific takeoff.
Is a concrete wall calculator structural design? + -
No. It estimates quantity only. Wall thickness, reinforcement, drainage, bracing, formwork, footing, and retaining-wall loads need project-specific engineering or contractor review.
Should poured walls use ready-mix? + -
Most full-height or long poured walls are better suited to ready-mix because placement timing and consistency matter. Bags are more realistic for small stem walls or repairs.