Is there a formula for correcting hydrometer reading for fluid temperature?

[Gilligan]

My hydrometers were made for use around 60 degrees F, if I remember correctly. I can't be sure, because they're all currently floating in cider carboys. The fluid temperature is 74 F according to the flexible temp tape glued to the carboys. I am wondering how far off my hydrometer reading is, in what direction does it err, and what is the formula to correct the reading for actual temperature.

 

[gunhaus]

There is a conversion chart in Palmers How To Brew 74 degrees would be +.0016

 

[VikeMan]

Higher temperatures give hydrometer readings that are too low. Most brewing software has a hydrometer temperature correction function.

 

[Gilligan]

Gunhaus, thank you!