A small 3 foot measuring tape should do the trick. I've got a mini plastic one in my kitchen, got it as a freebie, from the local hardware store.
18 multiplied by 33 is 594.
15'x33'x54" holds 16,662.9 US gallons of water.
The volume of water in a pool is caculated as followed Vol = area X Depth X 7.5 = gallons of water where as area is equal to width x length ( which is 18 x 33 ) so you need height or depth to finish the equations
There are 231 cu.in. in a gallon of water 18'= 216", 33'=396", multiplied together you have 85,539 sq.in. Multiply by the height (in inches) and devide by 231 and you get the gallons in the pool. 3'high=36" 85,539x36= 3,079,296 cu. in. 3,079,296 divided by 231 = 13,330.26 gallons.
I will assume you mean that the tiles are 14 inches square and that the room is 18 ft by 33 ft. 18 ft is 216 inches, and 33 ft is 396 inches. As a first approximation, the room is 85536 sq inches so dividing this by 14 squared, or 196. we get just over 436.4 squares. However, this is unlikely to be enough with cutting to fit. It's usual to start in the centre of the room and to lay as many full tiles as possible, then to cut tiles to fill in the borders. You'd need about 140 full tiles, depending on exactly where you start. The number of part tiles needed will then depend on whether they have a nap or not. I'd say you need at least another 21 to be sure.
We installed a 24' doughboy last year. It "wintered" well in our cold climate (northern il). Our grade was approx."1 in 3"...one wall began to indent badly this last week due to heavy rains and water trappage against wall. we had to dig down to within 1 1/2' of bottom of pool,install drain tiles (with holes)around that side. after digging the wall down,the wall dent "popped" back out. hope that helps you. We completed the installation of an 18x33 above ground in this manner last summer. I would recomend that you excavate 2'-3' beyond the pool wall and slope the side of the excavation so that the earth does not come in contact with the sidewalls. We installed a deck between the pool and the slope, creating a level walk out to the pool, and hiding the excavated area.
My above ground pool is 18" wide and 4" deep. Don't know if that's typical though. A: an inground pool would most likely be 15' x 30' x 8' deep - 3.5' in shallow end. Most typical is a kidney shaped in ground pool - 16' X 32' X 8' deep in center - 3.5' shallow ends