Snake Feeding Calculator: Prey Size & Schedule
Last updated: · Reviewed against sources listed below
Enter your snake's weight and age to get the right prey size and feeding schedule. This snake feeding calculator works for ball pythons and corn snakes and gives you a prey weight range, the rodent size to buy and how many days to wait between meals.
Your snake’s feeding plan
- Prey weight
- Prey size
- Feed every
- Prey per month
What the numbers mean: the prey weight is a range, not a single target. Anything inside it is a good meal. Stay at the lower end for adults that are already heavy, and weigh your snake every 2–4 weeks so you can adjust. If your snake regularly leaves a large bulge or regurgitates, move down a size.
How it works
The calculator uses a simple, widely used rule: prey weight = snake weight × a percentage. The percentage depends on life stage. Growing hatchlings and juveniles get 10–15% of their body weight per meal. Sub-adults get 10–12%, and adults get 5–10% because they mostly need to maintain weight rather than grow.
If you leave the age stage on Auto, the stage is chosen from weight using the cut-offs in the table below. Body condition then adjusts the plan. For an underweight snake we use the upper half of the percentage range and shorten the interval by about 15%. For an overweight snake we lower the percentage by 2 points and stretch the interval by about 50%.
Finally, the prey weight range is matched against typical feeder rodent weights to name the size to buy. Supplier labels vary, so always check the weight printed on the bag. The monthly count divides 30 days by the feeding interval so you know how many prey items to buy.
Reference data: feeding by life stage
Ball Python
| Stage | Snake weight | Prey (% of body weight) | Feed every |
|---|---|---|---|
| Hatchling | 0–200 g | 10–15% | 5–7 days |
| Juvenile | 200–500 g | 10–15% | 7–10 days |
| Sub-adult | 500–1,000 g | 10–12% | 10–14 days |
| Adult | 1,000 g and up | 5–10% | 14 days |
Corn Snake
| Stage | Snake weight | Prey (% of body weight) | Feed every |
|---|---|---|---|
| Hatchling | 0–50 g | 10–15% | 5–7 days |
| Juvenile | 50–200 g | 10–15% | 7–10 days |
| Sub-adult | 200–400 g | 10–12% | 10–14 days |
| Adult | 400 g and up | 5–10% | 14 days |
Hognose Snake
| Stage | Snake weight | Prey (% of body weight) | Feed every |
|---|---|---|---|
| Hatchling | 0–20 g | 10–15% | 4–5 days |
| Juvenile | 20–40 g | 10–15% | 5–7 days |
| Sub-adult | 40–80 g | 10–12% | 7–10 days |
| Adult | 80 g and up | 5–10% | 7–10 days |
Feeder rodent sizes
| Mouse size | Weight |
|---|---|
| Pinky | 1–3 g (0.04–0.11 oz)1–3 g |
| Fuzzy | 3–7 g (0.11–0.25 oz)3–7 g |
| Hopper | 7–13 g (0.25–0.46 oz)7–13 g |
| Weaned | 13–18 g (0.46–0.63 oz)13–18 g |
| Adult | 18–30 g (0.6–1.1 oz)18–30 g |
| Jumbo | 30–45 g (1.1–1.6 oz)30–45 g |
| Rat size | Weight |
|---|---|
| Pinky | 5–13 g (0.18–0.46 oz)5–13 g |
| Fuzzy | 13–20 g (0.46–0.71 oz)13–20 g |
| Pup | 20–30 g (0.7–1.1 oz)20–30 g |
| Weaned | 30–45 g (1.1–1.6 oz)30–45 g |
| Small | 45–85 g (1.6–3 oz)45–85 g |
| Medium | 85–150 g (3–5.3 oz)85–150 g |
| Large | 150–275 g (5.3–9.7 oz)150–275 g |
| X-large | 275–375 g (10–13 oz)275–375 g |
| Jumbo | 375–500 g (13–18 oz)375–500 g |
Frequently asked questions
How often should I feed a snake?
It depends on age. Hatchlings usually eat every 5–7 days, juveniles every 7–10 days, sub-adults every 10–14 days and adults about every 14 days for ball pythons or every 14–21 days for corn snakes. Young snakes are growing fast and need food more often. Adults mostly need to maintain weight, so longer gaps help prevent obesity. Use the calculator above for a range tailored to your snake’s weight.
How big should a snake’s prey be?
A common rule is prey that weighs about 10–15% of the snake’s body weight for growing snakes and 5–10% for adults. The prey should also be no wider than the widest part of the snake’s body. A small, visible lump after eating is normal; a very large bulge means the meal was too big.
Is it better to feed frozen-thawed or live prey?
Most vets and experienced keepers recommend frozen-thawed prey. It is safer because a live rodent can bite and seriously injure a snake, it is easier to store, and freezing reduces some parasite risk. Thaw prey in the fridge or in a sealed bag in warm water, never in the microwave, and offer it with tongs.
Should I switch my ball python from mice to rats?
Many keepers switch ball pythons to rats once the snake needs more than one adult mouse per meal, usually around 300–500 g. One rat of the right size is simpler than several mice, and rats provide more food per meal. Switch gradually, and scent the new prey with the old one if your snake is hesitant.
What if my snake refuses to eat?
Refusals are common, especially in ball pythons before a shed, during breeding season or in winter. Check temperatures and hides first, then try again in a week. See a reptile vet if your snake loses more than 10% of its body weight, looks thin, has a runny nose, mouth changes or refuses food for more than a few weeks as a juvenile.
Sources
- VCA Animal Hospitals — Snakes: Feeding
- Merck Veterinary Manual — Reptiles (Exotic and Laboratory Animals)
- VCA Animal Hospitals — Snakes: Owning
- Wildwood Veterinary Hospital — Ball Python Care
- ReptiFiles — Ball Python Feeding
- ReptiFiles — Corn Snake Food
- RodentPro — Guide to Frozen Feeder Mouse Sizes
- RodentPro — Frozen Rats (sizes by weight)
Where sources disagree we show the range they share. See our sources and methodology for how every number is checked.