Plumbing & HVAC calculators
Pipe and tank volume, pool gallons, pump flow, duct CFM and room BTU — capacities and flows in US or metric units. Every one works in feet and inches or in metric — flip the switch at the top and the numbers you have typed convert with it.
9 tools
- Pipe volume gallons or litres a pipe holds
- Pipe offset travel and cut length for 45°, 22½° and other fittings
- Gutter & downspouts roof runoff and how many downspouts
- Tank volume full or part-full cylinder capacity
- Pump GPM flow rate from a bucket test or pipe
- Duct CFM airflow from area & velocity or ACH
- Duct size round and rectangular size from your friction rate or velocity
- BTU / room heat heating or cooling load from your own factors
- Pool volume gallons or litres in a pool or pond
Nothing in this drawer matches. Try the full index, which searches every tool.
Which one do I need?
Capacities and flows in US gallons or litres, gpm or L/min, CFM or L/s — whichever your gauges read.
- Water held in a run of pipe? Pipe volume calculator →
- Gallons in a tank, full or part-full? Tank volume calculator →
- Gallons or litres in a pool? Pool volume calculator →
- Sizing a heater or an air conditioner? BTU calculator →
- Airflow in a duct? Duct CFM calculator →
- What size duct for the airflow? Duct size calculator →
The other drawers
- Concrete & masonry
- Framing & carpentry
- Site & landscape
- Finishes & interior
- Measure & layout
- Electrical
- Shop & equipment
- Conversions
- Every tool
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