Despite the importance of food intake, feed ration has not been determined for many crabs. Juvenile red king crabs of mean size 25–30 mm carapace length (CL) were fed to satiation with squid either once or twice weekly for 6 months. Feed ration (FR = consumption expressed as a proportion of wet body mass) increased to a peak of about 0.10 at 30 days premolt, dropped to 0.03 during molting, then increased to about 0.08 at 14 days postmolt. Data were analyzed using mixed-effects modeling with repeated measures. There was no significant effect of feeding frequency on FR, and no significant interaction between frequency and CL. There was a significant negative relationship between FR and CL, a significant positive relationship between FR and temperature, and a minor but significant interaction between CL and temperature. The FR for juvenile red king crabs is about half that of the ration previously reported for adult crabs. Daily feed ration is a valuable physiological index that can be used to understand the impacts of predators such as king crabs on benthic biomass in boreal ecosystems, and to determine feeding regimes for aquaculture and stock enhancement. The relationships determined by this study can be used to predict daily ration for king crabs under specific temperature conditions, and how this may vary with climate change.