How Much Concrete for a 14-Inch Round Footing 36 Inches Deep?
Concrete volume, cubic yards, and bag counts for a 14-inch diameter × 36-inch deep round footing
Exact quantities for a 14-inch diameter, 36-inch deep Sonotube footing — 3.207 cu ft (0.1188 yd³), plus 10% waste planning and bag counts for 40-, 60-, and 80-lb mixes.
At 36 inches deep this is a narrow, tube-form footing with a small pour volume. The footing measures 14 inches across and uses a cylindrical volume calculation for ordering concrete.
This size is often used for isolated post supports or where a narrow circular footprint is needed. Plan for excavation to full depth and a small waste allowance when buying bagged mix or scheduling deliveries.
Quick Answer
Exact volume: 3.207 cubic feet (0.1188 cubic yards).
Planning with 10% waste: 3.5277 cubic feet (0.1307 cubic yards). Exact bag counts: 11 40-lb bags, 8 60-lb bags, or 6 80-lb bags. Planning bag counts (with 10%): 12 40-lb bags, 8 60-lb bags, or 6 80-lb bags.
Need a custom estimate? Use the Footing Calculator. Browse footing size pages. All project pages.
How to Use This Footing Estimate
Quick steps to estimate and plan for a single 14" diameter × 36" deep round footing.
- Measure depth and diameter again on site — this example uses 14" diameter and 36" deep.
- Confirm the exact volume: 3.207 cu ft (0.1188 yd³) per footing.
- Add a waste allowance — this page uses 10% → 3.5277 cu ft (0.1307 yd³).
- Decide material: bags of concrete mix for one pour, or ready-mix delivery for multiple footings.
- Convert to bags: exact counts are 11 (40-lb), 8 (60-lb), or 6 (80-lb); planning counts are 12, 8, or 6 respectively.
- If you have several footings, multiply the planning volumes and bag counts before ordering.
Formula
Use this round footing formula:
Volume (ft³) = π × Radius (ft) × Radius (ft) × Depth (ft)
3.1416 × 0.58 × 0.58 × 3 = 3.21 ft³
3.21 ÷ 27 = 0.12 yd³
If you add a 10% waste allowance, you should plan closer to 0.13 cubic yards.
Worked Example
Single-footing example — before waste: 3.207 cu ft (0.1188 yd³). With 10% waste: 3.5277 cu ft (0.1307 yd³). Exact bags: 11 40-lb / 8 60-lb / 6 80-lb. Planning bags with waste: 12 40-lb / 8 60-lb / 6 80-lb.
Multiple-footing example (4 footings) — before waste: 12.828 cu ft (0.4752 yd³). With 10% waste: 14.1108 cu ft (0.5227 yd³). Exact bag totals: 44 40-lb, 32 60-lb, 24 80-lb. Planning bag totals with waste: 48 40-lb, 32 60-lb, 24 80-lb.
Bag Count Estimate
- 6 bags of 80 lb concrete mix
- 8 bags of 60 lb concrete mix
- 12 bags of 40 lb concrete mix
Always verify the actual yield on the product label before buying materials.
When Bagged Concrete vs Ready-Mix Makes Sense
For this single 14" × 36" footing, bagged concrete is often the simplest option. One person can mix a few 40- or 60-lb bags in a wheelbarrow and finish a small pour without scheduling a truck.
If you have several of these footings, ready-mix may become practical: a small delivery reduces on-site mixing time and gives consistent slump for multiple pours. For a handful of footings you still might prefer bags; for many footings a truck saves time and gives predictable yield.
Common Uses for This Footing Size
This 14-inch diameter by 36-inch deep footing is suited to isolated post supports where a narrow circular footprint is needed: deck posts, pergola posts, light sign supports, or similar single-point loads. It fits layouts that favor a small-diameter cylinder rather than a wide pad.
Limits depend on load, soil bearing value, frost depth, and reinforcement details. Reinforcement and footing depth affect capacity, so check design requirements and permit conditions before finalizing sizes and quantities.
Common Mistakes to Avoid
Common estimating and ordering mistakes for this footing size.
- Using the diameter instead of radius in the formula — leads to an under- or overestimate.
- Forgetting to add a waste allowance — you’ll run short on a small pour quickly.
- Mixing bag counts and planning counts together — list exact counts first, then planning counts with waste.
- Ordering ready-mix for a single small footing without considering delivery logistics.
- Not accounting for excavation overcut or forming space when laying out the Sonotube.
Frequently Asked Questions
What is the exact concrete volume for this 14-inch by 36-inch round footing?
The exact volume is 3.207 cubic feet, which is 0.1188 cubic yards.
How many bags do I need for a single footing?
Exact bag counts are 11 40-lb bags, 8 60-lb bags, or 6 80-lb bags. With a 10% waste allowance plan on 12 40-lb, 8 60-lb, or 6 80-lb bags.
Why include a 10% waste allowance?
A 10% allowance covers spillage, over-excavation, and small measurement differences so you don’t run short on a small pour.
Is this footing size adequate for a deck or pergola post?
It may work in some cases for a deck or pergola post, but adequacy depends on the applied load, soil bearing capacity, frost depth, and reinforcement. Confirm the structural requirements before final sizing.
Keep Planning Your Concrete Project
Use the calculator, compare more footing pages, and review your estimate before buying materials.
Disclaimer: This page provides planning estimates only. Actual concrete needs vary with excavation accuracy, site conditions, local code requirements, bag yield, and supplier guidance. Always verify measurements before buying materials, and consult a qualified professional for structural or code-sensitive work.