Switching to a prescription food in one jump often brings diarrhea or a refused bowl, so the new food is phased in over several days. Enter the total transition length and the number of steps from the product sheet or your veterinarian, and this tool lays out how much new food and how much old food to mix on each date. Add the daily total in ounces and it shows ounces per step as well.
Each step ratio is the step number divided by the number of steps, so the last step lands on 100% new food. Days per step are the transition length divided by the number of steps, and any leftover days are added one at a time to the earlier steps. Recommended transition lengths vary by product and condition, so this tool does not supply one. Figures are as of October 2026.
If diarrhea, vomiting or a drop in appetite shows up, the schedule should hold rather than advance. Which prescription food to use and how long to take over the change are decided by a veterinarian. This tool is for reference only and does not replace veterinary care. Contact your veterinarian right away if you notice symptoms or suspect a problem.
Frequently Asked Questions
It varies by product and condition, so this tool suggests no length. Use the number of days on the product sheet or the one your veterinarian gave you.
Each step needs at least one day, so the tool stops and shows a message instead of calculating. Reduce the steps to the number of days or fewer.
No. Hold at that step and call your veterinarian so the timing of the next step can be reset.