Plumbing
Plumbing GPM Calculator
Measure or estimate flow in gallons per minute, by timing a bucket or from fixture demand.
Result
The timed fill is the honest measurement and it is worth doing. Fixture demand figures here are typical simultaneous flows rather than code fixture units, which are a different system used for sizing rather than for measuring.
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About this calculator
How do I measure flow properly?
Time how long a known container takes to fill with the fixture wide open. A five gallon bucket and a phone timer is accurate enough for almost any sizing decision.
Do all fixtures run at once?
No, and assuming they do oversizes everything. Code fixture-unit tables exist precisely to apply a realistic diversity factor to simultaneous demand.
The formula
GPM = gallons / seconds x 60
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Estimating is the easy part
The jobs you never hear about cost more than the ones you mis-measure. BDEVY builds the marketing, systems and automation that bring them in.