What do you do if your object of interest is not as big as Wales or other small countries?

Why not try using WHALES instead of Wales?

The following utility will work out how many times larger than a blue whale your feature is. And if you just enter the length it will tell you how many times longer than a blue whale it is.

This "Whale-o-meter" will also give you an area (or length) comparison to the other common yardstick - the London bus.