Free calculator
How long does a bag of pet food last?
Work out how many days a bag lasts your dog or cat, how much they eat per day and when to reorder so you never run out.
- 1Choose dog or cat and its activity level.
- 2Enter its weight and the bag size.
- 3We tell you the grams per day, how many days it lasts and the ideal reorder date.
Rough estimate for a standard dry food (about 3.7 kcal per gram). Always follow your food’s feeding chart and your vet’s advice.
How it’s calculated
What your pet eats depends on its weight and how active it is.
We start from the resting energy an animal needs, which grows with its weight non-linearly (70 × weight0.75 kilocalories per day). We then multiply it by an activity factor: a calm dog needs less than one that runs every day, and an indoor cat less than one that goes outside.
We convert that energy into grams using the typical density of dry food, and the result tells us how long the bag lasts. That’s why a 10 kg dog can take more than two months to finish a 12 kg bag, while a 30 kg dog gets through it in under a month.
Every food is different: light formulas have fewer calories per gram and high-energy ones more. Use this calculation as a guide and adjust it with your brand’s chart.
Approximate duration of a 12 kg bag
| Dog’s weight | Grams per day | Days it lasts |
|---|---|---|
| 5 kg | 101 g | 119 days |
| 10 kg | 170 g | 70 days |
| 20 kg | 286 g | 42 days |
| 30 kg | 388 g | 31 days |
| 40 kg | 481 g | 25 days |
Adult dog with normal activity · standard dry food
For pet brands and stores
Do you sell pet food? This calculator can work for your store.
Knowing when each customer’s bag runs out is the foundation of repeat purchases: automatic reminders, subscriptions and offers at just the right moment. At TRILOGI we integrate it into your eCommerce and your CRM.
- Replenishment reminder by email or SMS, days before the bag runs out.
- Subscription with the frequency calculated for each pet.
- Product recommendations by species, age and size, with AI Agents.
- Learn more: how to sell pet food by subscription online.
Frequently asked questions
Common questions about pet food.
How much food does a 10 kg dog eat per day?
An adult 10 kg dog with normal activity needs about 630 kcal per day, which equals about 170 grams of a standard dry food. A very active dog may need quite a bit more, and a calm or neutered one a little less.
How long does a 12 kg bag of dog food last?
It depends on the dog’s size: for a 10 kg dog it lasts about 70 days; for a 20 kg dog, about 42; and for a 30 kg dog, roughly a month. You can calculate your exact case with the calculator on this page.
How much does a cat eat per day?
An adult 4 kg indoor cat usually needs about 240 kcal per day, about 65 grams of dry food. Cats that go outside or are very active need a little more.
When should I buy pet food again?
Ideally, buy about five days before the bag runs out, to allow time for shipping and avoid abrupt diet changes. Many online stores offer subscriptions or automatic reminders so you don’t have to think about it.