1 Your measurements

Type feet and inches the way you'd write them, like 12' 6" or 30 3/8. Decimals work too.

in
About 3× the post width: 10–12" for a 4×4, 12–16" for a 6×6.
in
Below your frost line. Typically ⅓ of the post length, minimum 24".
in
A few inches of gravel helps drainage. Enter 0 for none.
%

2 What to buy

80 lb bags
17
10.13 cu ft total
Per hole
0.92 cu ft
about 1.5 × 80 lb bags
Holes
10
24" of concrete each
Concrete, all holes (with waste)10.13 cu ft · 0.375 yd³ · 0.287 m³
40 lb bag34 bags
60 lb bag23 bags
80 lb bag17 bags
20 kg bag31 bags
25 kg bag25 bags
30 kg bag21 bags
Gravel for drainage2.73 cu ft (6 × 0.5 cu ft bags)

Fast-setting mix (like Quikrete Fast-Setting) is sold in 50 lb bags that yield about 0.375 cu ft. If you use it, buy 28 bags instead.

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