Deck Footing Count
Footings sit on a grid — divide each direction's length by the spacing, round up, and add one for the starting post. Multiplying the two counts gives the total number of footings.
Your numbers
Footings
20
Formula
Footings = (⌈Deck length ÷ Footing spacing⌉ + 1) × (⌈Deck width ÷ Footing spacing⌉ + 1)
Spacing usually stays under 90-120 cm so the edge boards don't sag. Soft ground calls for tighter spacing still.
What to enter
| Input | Default | Accepted range |
|---|---|---|
| Deck length (m) | 4 | 0.5 and up |
| Deck width (m) | 3 | 0.5 and up |
| Footing spacing (m) | 1.2 | 0.3 and up |
Step by step
Quick reference table
Results when only Deck length (m) changes and everything else stays put.
| Deck length (m) | Footings |
|---|---|
| 2 | 12 |
| 3 | 16 |
| 4 | 20 |
| 6 | 24 |
| 8 | 32 |
What each result means
| Result | At default values |
|---|---|
| FootingsFooting rows times footing columns. | 20 |
Common mistakes
Spacing usually stays under 90-120 cm so the edge boards don't sag. Soft ground calls for tighter spacing still.
Frequently asked questions
QHow is Deck Footing Count calculated?
Footings = (⌈Deck length ÷ Footing spacing⌉ + 1) × (⌈Deck width ÷ Footing spacing⌉ + 1) — Footings sit on a grid — divide each direction's length by the spacing, round up, and add one for the starting post. Multiplying the two counts gives the total number of footings.
QCan you walk through an example?
With Deck length 4m, Deck width 3m, Footing spacing 1.2m, the answer is Footings 20.
QWhat do I need to enter?
Enter Deck length, Deck width, Footing spacing. The result recalculates as you type, and an empty box counts as zero.
QHow much does the answer move if I change a number?
Changing only Deck length (m) moves the answer to Deck length (m) 2 → Footings 12 and Deck length (m) 8 → Footings 32. The table below lays out five steps.
QHow are the numbers rounded?
Money is shown to the nearest whole unit, percentages to one decimal place and everything else to two. What you see is rounded; the calculation itself carries the unrounded value forward.
QAnything to watch out for?
Spacing usually stays under 90-120 cm so the edge boards don't sag. Soft ground calls for tighter spacing still.
Related calculators
Keep your length units consistent across inputs — mixing centimetres and metres throws results far off.