How this calculator works
The ratio here compares buried depth with exposed height. QUIKRETE describes a preliminary depth of one-third to one-half of above-ground height, so the starting value is 0.5. Total length is the sum of exposed height and depth. Minimum embedment can increase depth; with fixed stock length it reduces the exposed portion. Soil, wind, gates and frost requirements remain separate design checks.
Formula
depth = ratio x exposed height; total length = exposed height + depth; exposed height from stock = total length/(1 + ratio), unless the minimum depth governs.
Worked example
At a depth-to-height ratio of 0.5, a 1.8 m exposed post needs 0.9 m below ground and 2.7 m total. A 3 m stock post at the same ratio leaves 2 m exposed.
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Frequently asked questions
Is one-third of total length the same ratio?
One-third of total length corresponds to depth/exposed height = 0.5. One-third of exposed height corresponds to 0.333, a different assumption.
Does a gravel layer count as embedment?
No. This tool measures the actual buried post. Add any required gravel bed below it when planning excavation depth.
Can this approve a gate post?
No. Gate loads, wind, soil resistance and local footing requirements can require a different design.