Calculated result
1yd³
Ready-mix order
Formula
CONC-POSTHOLE-00120.94 ft³
Net concrete volume
0.78 yd³
Net volume
52 bags
Bags to order
Concrete calculator
Post hole calculator
Concrete volume and bag count for round fence or deck post holes, including solid sonotube piers when post diameter is zero.
Reviewed formula · v1.0.0
Project inputs
Enter field measurements. Unit conversion happens before the reviewed formula is applied.
All values can be refined when you edit the estimate. This tool does not replace field verification or local requirements.
Transparent cost view
Use visible planning values, then replace them with actual job costs before quoting.
Material cost$85
Direct cost$475
Overhead + contingency$48
Markup + tax$63
Estimated project total$585
How this calculator works
A transparent post hole calculator takeoff.
This calculator treats each post hole as a round cylinder and subtracts the post when a diameter is entered, then applies a visible allowance before ready-mix rounding and bag count.
Worked example. Example: ten 12 in holes, 36 in deep, around 4 in posts contain about 20.94 ft³ of concrete. With 10% allowance the ready-mix order rounds to 1.00 yd³ and 52 bags at 0.45 ft³ each.
- 1. Measure hole or tube diameter and the actual post diameter, or enter 0 to fill the hole solid.
- 2. Enter identical-hole count and concrete depth, not the frost-line rule of thumb alone.
- 3. Replace bag yield with the selected mix label before treating bags as an order.
Need the broader workflow? Read the concrete planning guide.
Questions
Common questions about this post hole calculator.
Is this a sonotube calculator?
Enter 0 for post diameter to fill a cardboard tube or hole solid. That is a planning fill quantity, not a pier design.
Does this set hole depth or diameter?
No. Frost line, soil, post size and local requirements must be confirmed independently. This tool only estimates concrete quantity.