Length X width X Avg depth (all in ft) X 7.48 gal/cft = gallons
OR
Read your water meter before & after you fill it. Subtract avg daily (or hourly) usage. Difference remaining is your pool.
OR
If you have a manufactured pool, go to the manufacturer's website and look it up, if possible. If not, call them. Subtract 10% from their figure, since it will usually be gallons to overflow, rather than gallons to normal operating depth.
OR
Take pictures of the pool (might as well do the equip at the same time) and email them to poolforum AT gmail DOT com. I'll post them; we'll look at them and tell you what to do next.
Good luck!
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