Clearance Hole Calculator
Construction & Home ImprovementCalculate the recommended clearance hole diameter for a bolt or screw to pass through freely.
Clearance Hole Diameter
Recommended hole diameter for the fastener to pass through without threading.
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Creators
Odeh Ahwal0people find this calculator helpful
Views
Helpful
Saved
Embeds
Construction & Home Improvement calculators
Frequently Asked Questions
What is the difference between the three fit classes?
Close fit gives the tightest clearance, adding about 1/32 inch over the fastener diameter, useful when precise alignment matters. Normal or free fit adds about 1/16 inch, suitable for most general assembly. Loose fit adds about 1/8 inch, useful when parts need to shift slightly or when alignment is less precise.
Is this the exact ASME B18.2.8 standard value?
This uses a commonly cited rounded rule of thumb rather than the full ASME B18.2.8 per-size table, which specifies slightly different, size-dependent allowances. For precision work, check the exact standard table for your fastener size.
Does this apply to tapped or threaded holes?
No, this is for a clearance hole that a fastener passes freely through, not a hole that is threaded to grip the fastener.
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