There's a slight variance between 9mm and .38, about .002". The 9mm is .355" in OD (that's outside diameter) and .38 is actually .357" in OD. Those are what's known as "nominal" sizes, as in "Plus or minus .001".

The .357 Magnum is the same case as the .38 special, but it's .100" longer, and it's loaded to about twice as much chamber pressure, so it delivers about twice as much striking force.
The .44 mag is .429" in OD. The older revolver cases were loaded with black powder, ya see, as in the .44 Russian, the .38 Long Colt, the .41 Long Colt, 44-40. Their bullets had a reduced diameter "heel", like a .22 lr has. In other words, the bullet's OD was the same size as the OD of the brass cartridge case. The bullet's lubricant was on the outside of the bullet, and it was greasy. It picked up debris, and then sometimes couldn't be inserted into the chambers of the revolver. So the decision was made to make the entire bullet of an OD that would fit down inside the case. This meant that bullets either had to become smaller in OD, or the barrels, cylinders and frames had to be enlarged. It was much simpler to make the bullets smaller than to enlarge everything else. So the .32 came out to be .308", the .41 was actually .387", and so on. Cartridge "nomenclature" (ie, naming) is pretty arhaic and non-sensical in many ways.