Pet calculators that reckon what your pet actually needs
Free calculators for dogs, cats, fish and small pets: age, food portions, tank volume and stocking. Save a pet once and every tool pre-fills.
The calculators
Dogs
Your dog's age in human years, breed-size adjusted, not the Γ7 myth.
Cats
Your cat's age in human years using the real feline curve, not the Γ7 myth.
Dogs
How much to feed: daily calories and cups by weight, activity and life stage.
Fish & Aquarium
Tank gallons and liters from your dimensions: rectangle, cylinder, hex and more.
Fish & Aquarium
Bioload-based stocking guidance, not the oversimplified 1-inch-per-gallon rule.
The rules everyone repeats (and why they are wrong)
Both of these shortcuts are still quoted everywhere. Here is what the numbers actually do, and the method each calculator runs instead.
Myth-buster
The "multiply by 7" rule is a myth. Here is how dogs really age by size, and the breed-size-adjusted method vets use instead.
Myth-buster
Why the one-inch-per-gallon rule fails, and how bioload weighting, adult size, minimum tank size and group size really decide how many fish a tank holds.
Data you can cite
Statistics Β· CC BY 4.0 Β· CSV
Aquarium weight data for 29 glass tanks from 1 to 210 gallons: full weight per gallon (median 11.3 lb), floor load in psf, gravel and saltwater scenarios, CSV and chart.
The guides behind the numbers
Every calculator here runs a published method rather than a rule of thumb. These are the write-ups of what each one actually does.
- How Long Do Dogs Live? Dog Lifespan by Breed, in Dog and Human Years
- How Much Should I Feed My Dog? A Portion Guide That Uses Real Vet Math
- How Many Calories Does a Dog Need a Day? RER Formula, Calculator and Chart
- How Many Calories Does a Puppy Need? Calorie Chart by Age and Weight
- How Many Calories Does a Cat Need? How Much an Adult Cat Should Eat a Day
- How Much to Feed a Kitten: Calories and Meals by Age
- How Much Wet Food to Feed a Cat: Cans per Day by Weight
- Is Raw Dog Food Safe? What the Research Actually Says
- How Much Raw Food to Feed a Dog: BARF Portions by Body Weight
- How Many Fish in a 20 Gallon Tank? Stocking Plans That Actually Work
- How Much Does a Fish Tank Weigh? Full and Empty Weight by Gallon
- Aquarium Weight Statistics: Full Weight and Floor Load for 29 Tanks
- How Many Fish in a 10 Gallon Tank? Real Numbers by Species
- What Is Bioload in an Aquarium? How to Estimate Yours
- How to Cycle a New Fish Tank (Fishless Cycling, Step by Step)
- Puppy Growth Charts by Breed Size: What's Normal?
- How Many Litter Boxes Do You Actually Need?
- Human-Grade Dog Food: What It Actually Means (and How to Judge It)
Start with your pet
Each page runs the same engine against that breed, species or tank size, with the numbers worked out for you.
Dog age by breed
- Labrador Retriever age calculatorlarge, lives 13β14 yrs
- German Shepherd Dog age calculatorlarge, lives 11β12 yrs
- Golden Retriever age calculatorlarge, lives 13β14 yrs
- French Bulldog age calculatorsmall, lives 9β11 yrs
- Chihuahua age calculatortoy, lives 11β13 yrs
- Poodle (Standard) age calculatorlarge, lives 13β15 yrs
- Beagle age calculatorsmall, lives 12β15 yrs
- Dachshund age calculatorsmall, lives 13β14 yrs
- Shih Tzu age calculatorsmall, lives 12β14 yrs
- Great Dane age calculatorgiant, lives 10β12 yrs
- Border Collie age calculatormedium, lives 13β14 yrs
- Pug age calculatorsmall, lives 11β13 yrs
Mixed breed? Go by size
- Toy breed dogsup to 12 lb
- Small breed dogs13β25 lb
- Medium breed dogs26β50 lb
- Large breed dogs51β90 lb
- Giant breed dogsover 90 lb
Cat age by breed
- Abyssinian age calculatorlives 12β15 yrs
- Bengal age calculatorlives 12β16 yrs
- British Shorthair age calculatorlives 12β20 yrs
- Burmese age calculatorlives 16β18 yrs
- Exotic Shorthair age calculatorlives 12β15 yrs
- Maine Coon age calculatorlives 12β15 yrs
- Persian age calculatorlives 10β17 yrs
- Ragdoll age calculatorlives 12β17 yrs
- Russian Blue age calculatorlives 15β20 yrs
- Scottish Fold age calculatorlives 11β15 yrs
- Siamese age calculatorlives 12β20 yrs
- Sphynx age calculatorlives 8β14 yrs
Fish stocking by species
- Betta (Siamese Fighting Fish)5 gal minimum Β· low bioload
- Neon Tetra10 gal minimum Β· low bioload
- Guppy10 gal minimum Β· low bioload
- Fancy Goldfish30 gal minimum Β· high bioload
- Corydoras Catfish20 gal minimum Β· low bioload
- Angelfish30 gal minimum Β· medium bioload
- Oscar75 gal minimum Β· high bioload
- Common Pleco (Suckermouth Catfish)125 gal minimum Β· high bioload
Tank size reference
- 5 gallon tank16" Γ 8" Γ 10.5"
- 10 gallon tank20" Γ 10" Γ 12"
- 20 gallon tank24" Γ 12" Γ 16"
- 29 gallon tank30" Γ 12" Γ 18"
- 40 gallon tank36" Γ 18" Γ 16"
- 55 gallon tank48" Γ 13" Γ 21"
- 75 gallon tank48" Γ 18" Γ 21"
- 90 gallon tank48" Γ 18" Γ 24"
- 125 gallon tank72" Γ 18" Γ 21"
Tank volume by shape
- Rectangular tankslength Γ width Γ height Γ· 231
- Cube tanksedgeΒ³ Γ· 231
- Cylinder tanksΟ Γ (diameter Γ· 2)Β² Γ height Γ· 231
- Bowfront tankslength Γ width Γ height Γ 1.06 Γ· 231
- Hexagonal tanks(3β3 Γ· 2) Γ edgeΒ² Γ height Γ· 231
One saved pet, every tool
Add your pet in and their breed, weight and birthdate pre-fill the age, food and growth calculators, with no re-typing. Saved on your device only.