30 ft x 16 in x 8 in footing
- Cubic feet
- 29.3333333333
- 80 lb bags
- 49
- 60 lb bags
- 66
Footing size, reinforcement, soil bearing, frost depth, drainage, inspection rules, and local code need professional review.
Concrete Footing Calculator
Estimate cubic feet, cubic yards, 60 lb bags, and 80 lb bags for straight rectangular concrete footings from length, width, depth, and waste.
Inputs explainedResult checksExample valuesRuns in your browser
Formula steps
- Convert footing width and depth from inches to feet.
- Multiply length by width by depth for cubic feet.
- Add waste, convert to cubic yards, and estimate common bag counts.
Examples
Recent answers
Recent footing concrete estimates will appear here.
Concrete footing estimates stay local. This estimates material only, not footing design approval.
Inputs and recent answers stay in this browser tab and are not sent to a server.
How to use the Concrete Footing Calculator
- Enter footing length in feet, then width and depth in inches.
- Press Estimate footing to see cubic feet, cubic yards, and common concrete bag counts.
- Use cubic yards for ready-mix planning and bag counts for small hand-mix projects.
- Footing size, reinforcement, frost depth, soil, drainage, and code requirements need professional review.
What people use it for
Estimate concrete for a simple straight footing run.
Convert width and depth in inches into cubic yards.
Compare ready-mix volume with common bag counts.
Add a realistic waste cushion before pricing material.
Check a small footing repair against bag yield before shopping.
Quick examples
Garage footing run
30 ft long, 16 in wide, 8 in deep, 10% waste29.33 ft3, about 1.09 yd3, 49 eighty-pound bags
Garden wall footing
18 ft long, 12 in wide, 8 in deep, 8% waste12.96 ft3, about 0.48 yd3, 22 eighty-pound bags
Small repair footing
8 ft long, 10 in wide, 6 in deep, 5% waste3.5 ft3, about 0.13 yd3, 6 eighty-pound bags
Long foundation run
50 ft long, 24 in wide, 10 in deep, 10% waste91.67 ft3, about 3.4 yd3
Need the guide or a nearby tool?
Need a slower walkthrough, a related calculator, or the full library? These links keep you close to the task you started.
- How to use the Concrete Footing CalculatorSee slower examples, input meanings, formula notes, result limits, and mistakes to avoid.
- Home & ProjectsBrowse related calculators and utilities in the same category.
- Calculator and utility guidesFind more guides that use real tool inputs and example numbers.
- All free toolsSearch every live tool, converter, calculator, AI helper, and browser utility.
Frequently asked questions
Plain-language answers about when to use the tool, what it does with your inputs, what to double-check, and how privacy works.
When should I use the Concrete Footing Calculator?
Use it when your task matches one of these common needs: Estimate concrete for a simple straight footing run. Convert width and depth in inches into cubic yards. It works best when you already know the measurements, amounts, units, or options the page asks for.
What is the Concrete Footing Calculator doing with my inputs?
In plain language: The calculator converts footing width and depth from inches to feet, multiplies length by width by depth, adds the waste percent, converts cubic feet to cubic yards, and rounds 60 lb and 80 lb bag counts up. The examples on the page are there so you can compare your inputs with a worked example before copying the answer.
What do the main Concrete Footing Calculator inputs mean?
Footing length: the total straight run of the footing in feet. Footing width: the planned cross-section width in inches, not the wall width unless they match your drawing. Footing depth: the planned concrete thickness in inches. Waste percent: extra concrete for uneven trench bottoms, overdigging, spillage, and a small ordering cushion. Bag counts: rounded estimates using common dry-mix yields, useful for small hand-mixed jobs.
How should I read the Concrete Footing Calculator answer?
Read the headline estimate first, then check the material, waste, coverage, and unit lines. For project tools, the supporting lines are often the difference between a rough idea and a list you can actually shop from.
What should I double-check before trusting the answer?
This estimates concrete material after you already know the footing size. Soil bearing, loads, frost depth, reinforcement, drainage, slope, forms, inspections, and local code can change the real footing design. Also check the unit, scale, mode, and result limit because small input changes can change the answer.
Why does the Concrete Footing Calculator show both cubic yards and bags?
Cubic yards are useful for ready-mix orders, while 60 lb and 80 lb bag counts are useful for smaller hand-mixed projects. Large footings are usually better handled with a concrete supplier or contractor.
How do I calculate concrete for a footing?
Convert width and depth from inches to feet, multiply length x width x depth, add waste, then divide cubic feet by 27 to get cubic yards.
How much concrete is in a 30 ft by 16 in by 8 in footing?
With 10% waste, that footing is about 29.33 cubic feet, 1.09 cubic yards, 49 eighty-pound bags, or 66 sixty-pound bags.
Should I order bags or ready-mix for footings?
Small repairs can make sense with bags. Long footing runs usually become heavy fast, so cubic yards and a ready-mix quote are often easier to manage.
Does this include rebar?
No. It estimates concrete volume only. Use the Rebar Calculator for grid or bar counts and the Rebar Weight Calculator if you need steel weight.
Does this include footing cost?
Not directly. Use the cubic-yard result for ready-mix pricing or the rounded bag counts for store pricing, then add delivery, tools, forms, reinforcement, and labor separately.
What waste percent should I use?
For neat forms, 5% to 10% is a common planning cushion. Rough trenches, overdigging, uneven bottoms, and hand mixing may need more.
Can I use this for foundation footings?
Yes, for material volume after the footing size is chosen. It does not choose code-safe width, depth, reinforcement, frost depth, or soil-bearing design.
Can I use this for pier or post footings?
Only if the footing is rectangular. Use the Concrete Column Calculator or Post Hole Concrete Calculator for round tube forms or post holes.
Can this tell me the correct footing size?
No. It only estimates material from the size you enter. The right footing size depends on loads, soil, frost depth, reinforcement, and building rules.
Does the site save what I enter?
No. The calculator runs in your browser tab. Your recent answers stay only on the page while you use it, and they are not sent to a server.