When to Switch Puppy Food to Adult Food
Puppy food is calorie-dense and formulated to support rapid growth. Keep feeding it past the point your dog needs it, and you're overfeeding calories your now-slower-growing (or fully grown) dog doesn't need — a common, avoidable contributor to excess weight. The right time to switch depends on your dog's size, not a fixed age.
Switch timing by size
| Adult size | Switch to adult food at |
|---|---|
| Small (under 25 lb) | 9-10 months |
| Medium (25-50 lb) | 11-12 months |
| Large (50-90 lb) | 12-16 months |
| Giant (90+ lb) | 18-24 months |
These line up with when each size category has essentially finished growing — see our puppy growth stages guide for the full timeline. Not sure which category your dog falls into? Check your breed's guide or use the Puppy Weight Predictor.
How to make the switch without stomach upset
Sudden food changes are the most common cause of puppy diarrhea that has nothing to do with illness. Transition gradually over 7-10 days by mixing an increasing proportion of adult food into the puppy food:
- Days 1-2: 25% adult food, 75% puppy food
- Days 3-4: 50% adult food, 50% puppy food
- Days 5-6: 75% adult food, 25% puppy food
- Day 7+: 100% adult food
If you see loose stool at any stage, hold at that ratio for a couple more days before increasing the adult food proportion further, rather than pushing ahead on schedule.
Recalculate the amount, not just the food
A switch to adult food is also the right moment to recalculate feeding amount — adult maintenance formulas are typically less calorie-dense than puppy formulas, and your dog's energy needs per pound drop once growth slows.
Recalculate your dog's adult feeding amount
Switch the life stage setting to 'Adult' and get an updated daily calorie target and monthly cost for their new food.
Open the Dog Food Cost CalculatorLarge and giant breeds: one more consideration
If you have a large or giant breed, you likely already switched from a regular puppy formula to a large-breed puppy formula early on to control growth rate. The switch to adult food follows the same size-based timeline above — but because these breeds keep filling out well past 12 months, resist switching early just because your dog "looks done" growing in height. See our large breed care guide for more on pacing growth safely.