I wasn't sleeping thru math, but always needed as much help as possible. Here's something for now & maybe just in case, for later. Hope it helps http://www.fishlore.com/ConversionCalculator.htm
1 cubic cm = 1 ml of pure water. So 1000 cubic cm = 1 L. So, multiply your dimensions in cm lxwxh, and divide by 1000. I get a calculated volume of 214 L. The stated volume isn't always the same as the calculated value. Those may be the outer dimensions of the tank, whereas the volume would be dependent on the inner dimensions, hence the discrepancy.