Hay Feeding Calculator
Our calculator estimates how much hay your small pet needs. Ideal for rabbits, guinea pigs, chinchillas, degus, hamsters, gerbils, mice, rats and tortoises.
About the Tool
Small pets thrive on fibre. This tool turns the science of daily fibre requirements into an easy shopping plan. Tell us your pet type, weight, diet mix and how often you buy. We’ll calculate total hay required for that period, recommend the best box mix, and send you straight to the right product page.
Why it helps
Prevents under-feeding (and emergency top-ups).
Reduces waste with a realistic 10% buffer for spillage and foraging.
Converts pounds ↔ kilograms automatically.
Works for single pets or multi-pet households.
Tailors suggestions by species, age and hay type.
How the Logic Works
species_daily_rate = baseline % of bodyweight eaten as hay per day (by species).
age_multiplier = adjustment for Young/Adult/Senior.
1.10 buffer = allows for mess, enrichment and natural variation.
Inputs, defaults & constants
| Parameter | Value / Options |
|---|---|
| Species → Baseline daily rate (% BW) | Rabbit 0.06, Guinea Pig 0.07, Chinchilla 0.05, Degu 0.04, Hamster 0.03, Gerbil 0.03, Mouse 0.03, Rat 0.03, Tortoise 0.04 |
| Age multiplier | Young 1.15 · Adult 1.00 · Senior 0.95 |
| Diet % hay (slider) | 50%–100% (default 80%) |
| Re-order frequency | 7 / 14 / 28 / 56 days |
| Animals | 1+ |
| Weight (kg or lbs) | User entry; if blank uses species default — Rabbit 2.0, Guinea Pig 1.0, Chinchilla 0.6, Degu 0.25, Hamster 0.15, Gerbil 0.10, Mouse 0.03, Rat 0.45, Tortoise 0.80 kg |
| Units conversion | lbs → kg × 0.45359237 |
| Waste/spillage buffer | +10% |
How to Use the Calculator
Choose your pet (e.g., Rabbit or Guinea Pig).
Pick an age group (Young, Adult, Senior).
Enter weight (kg or lbs). Leave blank to use a sensible default.
Set hay % of diet (we recommend 80%+).
Choose how often you buy (weekly to every 8 weeks).
Add the number of animals and select hay type.
Hit Calculate to see total kg (and lbs), a recommended pack mix, a storage tip, and direct links to Shop or Browse per species.
Use Clear Results to reset the output without losing your inputs.
Frequently Asked Questions
1. How accurate is the calculator?
It’s designed for practical feeding rather than clinical dosing. We combine species intake norms with age and diet mix, plus a 10% buffer. Individual appetites, exercise levels and seasons vary — always monitor body condition and adjust.
2. I don’t know my pet’s exact weight. Can I still use it?
Yes. Leave weight blank and we’ll use a species default (e.g., Rabbit 2.0 kg, Guinea Pig 1.0 kg). For best accuracy, weigh your pet monthly.
3. Why do you recommend 80% hay?
For most small herbivores, a hay-first diet supports gut motility, dental wear and mental enrichment. Pellets and greens are complements, not substitutes.
4. Can I use this for multiple pets in one cage?
Absolutely. Set Number of Animals to your total. If their sizes differ a lot, run separate calculations and combine the results.
5. What if my pet is overweight/underweight or has special needs?
Use the calculator as a starting point, then reduce or increase slightly while tracking weight weekly. If your pet has a medical condition, ask your vet before changing diet.
6. Timothy vs Meadow vs Three-Tie vs Sweet Rye: what’s the difference?
Timothy Hay: balanced, crunchy stems, great daily staple.
Meadow Hay: softer blend, high variety and aroma; brilliant for foraging.
Three-Tie Timothy: premium US Timothy, very green with large seed heads.
Sweet Rye: naturally sweet aroma and coarse stalks for enthusiastic chewers.
7. My pet wastes hay. Can I lower the buffer?
The 10% buffer is built-in to prevent mid-cycle shortages. If your pet is especially tidy, you can manually reduce your buy frequency or choose a smaller pack mix.
8. Does the calculator include bedding hay?
No, it focuses on feeding. If you also use hay as bedding/enrichment, consider rounding up one extra 1 kg bag per cycle.
9. Can I switch hay types suddenly?
Yes, but mix for a few days to encourage acceptance. Many owners rotate types to keep interest high.
10. Do you offer subscriptions?
You can set a repeat schedule that matches your calculation (e.g., every 4 weeks) so hay arrives when you need it.
Assumptions & Limitations (important)
Based on healthy animals with normal activity.
Age bands are broad; individual needs vary.
Results are estimates, so always observe appetite, droppings and body condition.
This tool does not replace veterinary advice.