Work out gallons inside a pipe so you can plan flushing, antifreeze or the weight on supports.
How it works
Area of a circle from the inside diameter, times length, gives cubic feet. Each cubic foot holds 7.48 gallons.
Before you order
- Inside diameter differs from nominal pipe size, so check the pipe chart for your material.
- Add extra for tanks, boilers and coils when working out system fluid.
- Water weighs about 8.34 lb per gallon when planning hanger spacing.
Common questions
Why does the nominal size not match?
Nominal sizes are trade names. Actual inside diameter depends on the material and wall thickness.
How do I find glycol volume for a loop?
Add this pipe volume to the volume of the boiler or tank, then follow the glycol maker's mix chart.