Baluster calculator

Fit equal-width balusters with equal gaps at both ends: n = ceiling((span − maximum gap)/(width + maximum gap)).

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Clear span between posts

Baluster width

More inputs and assumptions

Your maximum clear gap

Answer

…

Fit equal-width balusters with equal gaps at both ends: n = ceiling((span − maximum gap)/(width + maximum gap)).

More results

Precision and calculation record

Decimal places in numeric results and text downloads

Rounding changes displayed numbers, not the calculation. Text, fractions, matrices and CSV schedules keep their own formatting. Automatic keeps up to 12 significant digits, with money shown to cents where applicable.

Saved scenario

Save the current answer, then change an input to compare. This clears when you leave.

Formula and assumptions

Use one unit throughout. Maximum gap is your design input, not a building-code recommendation. Posts are outside the clear span; this does not assess structural or code compliance.

Automatic precision shows numbers to 12 significant digits. Thousands separators such as 1,000 are accepted; use a dot for decimals.

Scratch calculator

Check another calculation

Use +, −, ×, ÷, parentheses and %. A percentage is divided by 100. This does not change the main tool.

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Updated 2026-09-26

Using Baluster calculator

Fit equal-width balusters with equal gaps at both ends: n = ceiling((span − maximum gap)/(width + maximum gap)).

Use one unit throughout. Maximum gap is your design input, not a building-code recommendation. Posts are outside the clear span; this does not assess structural or code compliance.

Next: Fence calculator

A worked example

Example inputs: clear span between posts = 100, baluster width = 2, your maximum clear gap = 4. Balusters needed = 16.

Before you use the result

Use one unit throughout. Maximum gap is your design input, not a building-code recommendation. Posts are outside the clear span; this does not assess structural or code compliance.

Example results for clear span between posts

These examples use Baluster width: 2; Your maximum clear gap: 4. They are reference calculations, not recommended settings.

Clear span between posts	Balusters needed
50	8
100	16
200	33

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