Rabbit Weight Calculator

In 2026, the PDSA PAW Report estimated that 30%+ of UK pet rabbits are overweight or obese. The horizontal marker bar exists because rabbit owners read a single number on a scale and have no reference for whether 4.5 lb is healthy for a Holland Lop (it is the breed max — borderline) or a Mini Rex (it is +12% over the show mean and inside the overweight band).

Rabbit weight standards began in Flanders in the 16th century where giant rabbits (the ancestors of the modern Flemish Giant) were bred for meat and pelts. The American Rabbit Breeders Association (ARBA) was founded in 1910 and standardized breed weight ranges in the 1920s; the current Standard of Perfection (updated every 5 years) is the legal reference for show competition in North America.

The British Rabbit Council (BRC) maintains a parallel standard for the UK and Europe — Continental Giant standards live there but not in ARBA. The Rabbit Welfare Association & Fund (RWAF) publishes a pet-focused weight survey based on RWAF-registered vets; the survey shows that pet weight medians sit 5-12% above show-mean across most breeds, partly genetics and partly diet.

Body condition scoring (BCS) is a vet-clinic alternative — a 1-5 or 1-9 scale based on rib palpation and visual silhouette. BCS captures muscle vs fat where pure weight cannot; this calculator pairs with BCS by using breed-percent bands to flag obesity but trusts the vet exam for final ruling. For BCS-based scoring, see the sibling cat BCS calculator — the same five-point scoring applies to rabbits with the dewlap removed from the calculation.

Pododermatitis (sore hocks) is the silent companion of rabbit obesity. Extra mass on the rear footpads causes ulceration and infection; Flemish Giants, Rex (whose underfoot fur is sparse), and obese Mini Lops are over-represented at exotic vet clinics for pododermatitis treatment. The advice block at +15% over mean flags this proactively.

Uterine adenocarcinoma is the largest single cause of premature death in intact does. RWAF data shows 80%+ lifetime risk in unspayed females by age 5; the cancer commonly presents as unexplained weight gain (the tumor is heavy and abdominally distended). Intact does past 2 years sitting above the breed mean automatically get a spay-and-biopsy flag in this calculator.

The marker bar visualization was inspired by the engineering tolerance bands used in NEMA motor standards — a known-good range with risk zones either side. Substituting ARBA breed ranges for NEMA tolerance ranges keeps the same precision principle: there is a target window, not a single point. Related rabbit tools: rabbit age calculator, rabbit food calculator, rabbit hutch size calculator.