What Size Rat for a Ball Python? A Grams-by-Weight Guide

What size rat for a ball python? Feed a rat that weighs about 10% to 15% of your snake's weight, and no wider than its mid-body. A 500 g ball python takes a rat around 50 to 75 g, a Small. A 1,000 g snake takes about 100 to 150 g, a Medium. Weigh your snake first, then match by grams.

That's the answer to "what size rat should I feed my ball python?" in one breath. Below you'll find a full chart, signs a rat is too big or too small, and how to weigh your snake at home.

Not sure which size fits? Text Mike your snake's weight at (520) 451-4380, and he'll help you pick.

The 10% to 15% Rule in Plain Numbers

Two checks tell you what size rat to feed your ball python.

Check 1: Weight. ReptiFiles suggests feeders that weigh 10% to 15% of your ball python's body weight. Its example: a 400 g snake takes feeders of about 40 to 60 g (ReptiFiles).

Check 2: Width. PetMD's vet-written care sheet says prey should be about the same size as the snake's width at mid-body. If the midsection is 1.5 inches across, the prey should be no wider than 1.5 inches (PetMD). Chewy's vet-reviewed guide says prey more than about 1.25 times the widest part of the snake is too big (Chewy).

Use the weight to pick a size. Use the width as a final check.

Ball Python Weight to Rat Size Chart

Here's the math done for you. The middle column is 10% to 15% of the snake's weight. The last column is the closest of Mike's sizes.

What size rat for a 500 g ball python? A Small rat. Small is 45 to 85 g, and the target for a 500 g snake is 50 to 75 g.

Medium rats for ball pythons: Medium is 85 to 175 g. By the 10% rule, that fits snakes around 850 g to 1.75 kg.

Small rats for ball pythons: Small is 45 to 85 g. That fits snakes around 450 to 850 g.

Here are Mike's rat sizes with prices:

Prices are per animal, plus Arizona sales tax. Buy more and pay less: 10% off each at 10 or more, 20% off at 25 or more, and 30% off at 50 or more. Sold as feeders, not pets. The "good for" column uses the 10% rule. Grams show how big each size is; the feeder size guide has the full chart.

What Size Rat for a Baby Ball Python?

Baby ball pythons usually start on mice. PetMD says to start young ball pythons on small mice and move to larger mice and rats as they grow (PetMD).

Use the same 10% to 15% rule. Mike's mice come in three sizes:

Prices are per animal, plus Arizona sales tax. Sold as feeders, not pets. Mike doesn't sell pinkies or fuzzies, so his smallest size is the Hopper. See the live feeder mice page.

Once your snake reaches about 300 to 450 g, a Small rat near 45 g fits the 10% to 15% rule. Our guide Switching a Ball Python From Mice to Rats covers how to make the change.

Signs a Rat Is Too Big or Too Small

The chart gets you close. Your snake tells you the rest.

Signs the rat may be too big:

• It's wider than your snake's mid-body (PetMD).
• It's more than about 1.25 times the widest part of your snake (Chewy).
• It weighs well over 15% of your snake's weight (ReptiFiles).

If your snake struggles to swallow, gives up partway, or brings the meal back up, size down next time and talk to a reptile vet if it happens again. Our guide Snake Regurgitation explains what to do after a meal comes back up.

A lump in the body after a meal is normal. VCA notes that sometimes a lump "is simply the food a snake has just eaten" (VCA).

Signs the rat may be too small:

• It's under 10% of your snake's weight.
• Your snake has grown past the "good for" range of its current size.

If that's the case, move up a size. For how often to feed, see How Often to Feed a Ball Python.

Adults: What Size Rat for an Adult Ball Python?

Use the same rule for adults: 10% to 15% of the snake's weight, no wider than mid-body. For a 1,000 to 2,000 g snake, that lands on a Medium or a Large.

What changes with adults is how often they eat, not the rule. Adults eat less often than young snakes:

• VCA says larger, mature snakes usually eat once every one to two weeks (VCA).
• PetMD says adult ball pythons need to eat every 1 to 2 weeks.
• Chewy notes many keepers feed adults three to six weeks apart.

So for a big adult, you don't need to keep moving up in size. Stay in the 10% to 15% range and space meals out. Our ball python weight chart shows where your snake sits by age.

How to Weigh Your Ball Python at Home

You only need a kitchen scale that reads grams.

1. Put a bin or bag on the scale. Use one your snake can't climb out of.
2. Zero the scale with the empty bin on it.
3. Add your snake. Wait for it to settle.
4. Read the grams and write them down with the date.

ReptiFiles suggests weighing once a week to track your snake's weight (ReptiFiles). Weigh before feeding, not right after a meal.

Why Sizes Differ Between Sellers

"Medium" doesn't mean the same thing everywhere. Each seller draws its own lines.

That's why grams beat size names. Always check the weight range, not the label. Mike lists grams next to every size.

Pick the Right Size, Then Text Mike

Weigh your snake in grams. Aim for a rat about 10% to 15% of that weight, no wider than its mid-body. Check the chart, then check your snake.

Feeding live? Read How to Feed Live Rats to Snakes Safely first. Need rats in the Tucson area? Text Mike your snake's weight at (520) 451-4380, and he'll help you pick. Mike replies the same day.

Nothing ready in your size? Get batch alerts and Mike will email you when a new batch is ready.