Glass Hydrometer - Specific Gravity/Temp. Conversion

[bassetbros]

I purchased a glass hydrometer the other day but no instructions came with it in relation specific gravity and temperature. I've read online that if the water to be tested is between 75-80 degrees, then .002 needs to be added to the reading given by the hydrometer. This .002 correction is supposedly needed because the hydrometer is calibrated at 60 degrees.

So, if I'm trying to make up a batch of water change water with a s.g. of 1.026 that is heated to 80 degrees, my hydrometer should read 1.024. Correct?

Is this really the case or is there a more accurate conversion? Thanks!