Calculate the number of joists, hangers, and blocking needed for floors and ceilings.
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How to Use This Calculator
<h4>How to Use</h4><ol><li>Enter the room length (direction joists are spaced along).</li><li>Enter the room width (joist span direction).</li><li>Select the joist spacing – 16" (400 mm) is standard for floors.</li><li>Results show joist count, hangers, blocking, and rim joists.</li></ol><h4>Tips</h4><ul><li>Joists should span the shorter room dimension where possible.</li><li>Add blocking (nogging) at mid-span for stability.</li><li>Use joist hangers at each bearing point for code compliance.</li></ul>
Common Questions
What spacing should floor joists be?
16 inches (400 mm) on center is standard for residential floors. 12 inches may be needed for heavier loads like tile floors.
How far can joists span?
It depends on the joist size and wood species. A 2×10 SPF joist at 16" spacing can typically span around 15 feet for a 40 psf live load.
Do I need blocking between joists?
Yes, bridging or blocking is required at mid-span (or every 8 ft) for stability and to prevent joist twisting under load.