Construction
Pipe Thread Engagement Calculator
NPT thread engagement depths for a leak-tight joint. Under-engagement leaks; over-engagement strips threads.
Min hand-tight (turns)
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- Wrench turns
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- Total engagement (in)
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- Thread depth (TPI)
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FAQ
Hand-tight then wrench? +
Yes — finger-tight to engagement (4-5 turns) then 2-3 turns with a wrench. Past that you risk splitting fittings.
PTFE tape or pipe dope? +
Either works. Tape wraps clockwise 2-3 turns. Dope is messier but better on larger sizes and gas service.