Wood Post Calculator

Estimate wood post load, compression stress, slenderness ratio, buckling load, footing pressure, required bearing area, and simplified utilization. Use this wood post calculator for deck posts, porch posts, beam support posts, basement posts, pergola posts, timber posts, and preliminary structural planning.

Calculate Wood Post

Wood post load = tributary area × area load + beam reaction + point load + post self weight. Compression stress = load ÷ post area.
Your result will appear here.

How the wood post calculator works

Load estimate:
The calculator estimates wood post load from tributary area, dead load, live load, roof or snow load, beam reaction, point load, and post self weight.

Post section:
The calculator uses post width, depth, shape, and height to estimate area, weak-axis moment of inertia, and radius of gyration.

Compression and buckling:
The calculator estimates compression stress, compression capacity, slenderness ratio, and Euler buckling load.

Footing check:
The calculator estimates footing pressure and compares it with allowable soil bearing.

Why use a wood post calculator?

A wood post calculator helps estimate whether a post size may be reasonable for a vertical support load.

It can help compare post load, post size, compression stress, slenderness, buckling load, footing pressure, and required footing area.

What your result means

Your result shows estimated tributary area, area load, total wood post load, compression stress, compression utilization, slenderness ratio, Euler buckling estimate, footing pressure, footing utilization, and required footing size. These are simplified planning estimates only.

Wood post formulas

Frequently asked questions

How do you calculate wood post load?

Estimate the tributary area carried by the post, multiply by the design load, then add beam reactions, point loads, and post self weight.

What size is a 6×6 wood post?

Many dressed 6×6 posts are about 5.5 inches by 5.5 inches actual size, but actual dimensions can vary by product and supplier.

What controls wood post capacity?

Wood post capacity can be controlled by compression stress, buckling, unsupported height, bracing, species, grade, moisture, load duration, bearing, and connections.

Can this replace code-approved post sizing?

No. Final wood post design should follow local building code, deck tables, lumber species and grade rules, bracing requirements, footing requirements, connection hardware, and professional review when needed.