Pets Calculators
Plan for your animals with simple, honest estimates. Predict how big a puppy will grow, work out how many gallons a fish tank really holds and see how much feed a backyard flock gets through in a month. Each calculator shows its formula and says how far to trust the answer.
Estimate your puppy's adult weightAquarium Volume Calculator
Gallons, litres and water weight for any tank shapeChicken Feed Calculator
Feed per day, bags and cost for your flock
Which calculator do I need?
| Calculator | Question it answers | What you enter | What you get |
|---|---|---|---|
| Puppy weight | How big will my puppy get? | Age, current weight and breed size | An adult weight estimate with a range |
| Aquarium volume | How many gallons does my tank hold? | Tank shape and measurements | Gallons, litres and water weight |
| Chicken feed | How much feed does my flock need? | Number of birds, bag size and price | Pounds per day, bags and cost |
How to read these estimates
Animals are not as predictable as gravel or invoices. A puppy's adult size depends mostly on its parents, a hen eats more in January than in July, and a tank full of rock holds less water than its label says. Each of these calculators gives you a sensible starting number and tells you where it came from, so you can plan a crate, a feed order or a water change. They are not a substitute for a vet's advice about an individual animal.
Where the numbers come from
The aquarium calculator is plain geometry: volume from the shape and size, converted at 231 cubic inches to the US gallon. The chicken feed calculator starts from the university extension figure of about a quarter of a pound of feed per laying hen per day and lets you change it. The puppy calculator uses well-known rules of thumb, such as a medium breed reaching about half its adult weight at four months, and says plainly that they are rules of thumb. Every page shows its formula and a worked example.
Tips for better results
- Measure, do not guess. Weigh the puppy on the same scale each week, and measure the inside of the tank if you can.
- Edit the defaults. If your feed bag or your vet gives a different figure, type it in. The calculators are built to be adjusted.
- Plan with a margin. Order a little extra feed, and treat a predicted adult weight as a range.
More pet calculators are planned
We add tools based on what people ask for. If there is a pet or small-farm sum you do often, tell us on the contact page.