Anchor Bolt Calculator

Calculate anchor bolt quantity and spacing for sill plates, mudsills, and holdowns. Determine bolt diameter and embedment depth.

πŸ”© Anchor Bolt Calculator

Results

Bolts per Wall8
Total Anchor Bolts32 bolts
Min. Embedment7 in
Nut & Washer Sets32 sets

πŸ’‘ How to Calculate Anchor Bolt Requirements

Anchor bolts (J-bolts or L-bolts) secure the wood sill plate to the concrete foundation. IRC code requires a minimum 1/2-inch diameter bolt embedded at least 7 inches into concrete, spaced no more than 6 feet apart, with a bolt within 12 inches of each end of each sill plate piece.

In high-wind and seismic zones, spacing may be reduced to 4 feet or 32 inches. Holdown brackets at shear wall ends require additional anchor bolts β€” typically 5/8-inch or 3/4-inch diameter with deeper embedment. Always check your local building code for specific requirements.

A 40 ft wall at 6 ft spacing: 40 / 6 + 1 = 8 bolts per wall. Four walls = 32 anchor bolts total. With 1/2-inch bolts, minimum 7-inch embedment into concrete.

Anchor Bolt Calculator FAQ

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