Baluster Spacing Calculator
Use this tool to calculate how many balusters you need for a railing or stair run to meet common spacing guidelines based on your rail length and spacing requirements. The resulting actual spacing is shown for reference only.
Great for homeowners, builders, stair installers, architects, contractors, and more who prefer minimal guesswork.
How to Use the Calculator
- 1
Enter the total length of your handrail in inches. Note: Local codes may vary. Contact your city’s building department or a licensed contractor to verify what’s required. You can also search online using terms like “[your city] stair baluster spacing code.” Reference links listed on this page below are for convenience only and may not reflect the most up-to-date code.
- 2Enter the width of the balusters you’re using from the narrowest point on the baluster.
- 3Choose either the default spacing or a custom spacing. If you choose custom spacing, enter your preferred distance between balusters.*
- 4The results will calculate automatically.
*Disclaimer: This calculator is intended for general planning purposes only. Always confirm spacing requirements with your local building code authority. H. Arnold Wood Turning, Inc. is not liable for any installation or compliance issues resulting from use of this tool.
Check Your Local Code Requirements Below
While this calculator uses the typical 4″ spacing guideline based on the International Residential Code (IRC), local or state amendments may differ.
Use the links below to view building code resources or summaries for your state to ensure full compliance. This list is not exhaustive, and building codes are subject to change. It is the user’s responsibility to confirm the most current and applicable spacing requirements with their local building authority.
All Other States (Shown Here) Generally Follow IRC R312.1
While some states publish amended building codes, the following states generally adopt IRC R312.1 for guard openings and baluster spacing without modifications. This means spacing must typically prevent a 4″ sphere from passing through.
Always confirm with your local building department for any regional amendments or enforcement differences.
Need Bulk or Custom Wood Balusters?
We manufacture custom wood balusters and stair components for homeowners, as well as large-scale production and contractor orders. Whether you need precision milled parts or architectural turnings, we deliver high-quality wood components made to spec.
Reach out to us today for more information and to receive a free, custom quote with zero obligation to purchase!
Frequently Asked Questions (FAQs)
- All
- Baluster Calculator – Accuracy & Adjustments
- Baluster Calculator – Design Flexibility
- Baluster Calculator – Usage
Yes, just be sure to measure the length of the handrail along the angle, not the floor. The logic remains the same.
Yes. You can select the “Custom” spacing option and input any distance you prefer between balusters. This allows for unique designs or local code variations.
The tool calculates the best fit and adjusts spacing between balusters automatically, rounding up when necessary to help meet code spacing.
If the calculated spacing exceeds 4”, the calculator adds a baluster to help bring the spacing under typical code limits.
The default 4″ spacing is based on common U.S. residential building code, which requires openings between balusters to be less than 4 inches. Always confirm spacing requirements with your local building code authority.
Enter your rail length, baluster width, and choose either the default 4″ spacing or input a custom value. The tool automatically calculates how many balusters you need and what your actual spacing will be.