What is the standard garden bench seat height?

The standard garden bench seat height is 430-460mm from the ground. This is slightly lower than indoor dining chairs to create a relaxed seating position. For elderly users, a slightly higher seat (480-500mm) makes it easier to stand up.

What timber should I use for a garden bench?

The best options are: oak (extremely durable, weathers to silver grey), iroko or teak (naturally rot-resistant, expensive), or pressure-treated softwood (budget-friendly, needs UC3 rating minimum). Cedar is also good for outdoor use. Always use stainless steel or coated fixings.

How wide should a garden bench seat be?

A garden bench seat depth of 380-420mm is comfortable. Wider than 450mm and it becomes hard to lean against the backrest. Each seating position should be about 500-600mm wide for comfort. A 3-seater bench is typically 1500mm long.

Should I treat my garden bench?

Softwood benches should be treated with an exterior wood preservative or oil annually. Hardwood benches can be left to weather naturally to silver grey, or maintained with teak oil or similar to preserve the colour. Apply treatment in dry, mild weather.

WoodCalcs

Garden Bench Calculator — Timber Quantities & Dimensions

Calculate timber quantities and dimensions for a garden bench build.

Bench Size

Seat Depth

Seat Height

Slat Width

Slat Thickness

Timber Price per Metre (optional)

How We Calculate This

This calculator estimates the timber needed for a traditional garden bench with seat slats, optional backrest, legs, and structural braces.

Slat calculation

Seat slats = ceil(Seat depth / (Slat width + 5mm gap))

Back slats = ceil(400mm backrest height / (Slat width + 5mm gap))

Timber total

Total timber includes: all slats at bench length, 4 legs at full height, 2 armrests at seat depth, and 3 cross braces at bench length. All measurements are converted to linear metres.

Frequently Asked Questions

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Last updated: February 2026

All calculations are estimates. Always verify measurements and material quantities before cutting or purchasing.