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How much calcium does your dog actually need? This tool applies FEDIAF 2021 (130 mg/kg^0.75 for adults, 320 mg/kg^0.75 for puppies) and converts the requirement into grams of raw meaty bone or crushed eggshell. Target Ca:P ratio: 1.2-1.4:1.
Minimum calcium / day
1,229 mg
Raw meaty bone
6 g
Eggshell
3.2 g
Target Ca:P ratio
1.2 to 1.4 : 1
Formula: Ca (mg) = 130 x BW^0.75 (adult) or 320 x BW^0.75 (puppy). Raw meaty bone: ~200 mg Ca/g. Eggshell: ~380 mg Ca/g.
| Weight | Adult | Puppy | Bone equivalent (adult) | Eggshell (adult) |
|---|---|---|---|---|
| 10 kg | 731 mg | 1,799 mg | 4 g | 1.9 g |
| 20 kg | 1,229 mg | 3,026 mg | 6 g | 3.2 g |
| 30 kg | 1,666 mg | 4,102 mg | 8 g | 4.4 g |
| 45 kg | 2,259 mg | 5,560 mg | 11 g | 5.9 g |
FEDIAF 2021 sets an absolute maximum of 1.8% calcium on a dry-matter basis for large and giant-breed puppies. Excess calcium between 3 and 6 months disrupts bone remodeling and raises the risk of osteochondritis dissecans, HOD and dysplasia. Stay close to the minimum requirement, never heavy-supplement.
A 40 kg dog's metabolism isn't 4x that of a 10 kg dog. FEDIAF and NRC use metabolic body weight (BW^0.75) to capture this non-linearity. It's more accurate than a flat percentage of body weight.
Raw meaty bones deliver calcium + phosphorus + trace minerals + chewing. Crushed eggshell is pure calcium, useful when bones aren't an option (toy breeds, fragile jaws, seniors). Both are compatible with BARF.
For a healthy adult, 10% raw meaty bone in the ration usually covers calcium needs and hits a Ca:P ratio of 1.2-1.4:1. Cross-check with this calculator by comparing your actual bone grams to the computed requirement.
Yes — up to roughly 2x the minimum for an adult (FEDIAF allows up to 2.5% Ca on dry matter). Beyond that, digestive and urinary risk rises. For large-breed puppies, never exceed 1.8% Ca on dry matter.
Source: FEDIAF Nutritional Guidelines 2021, NRC Nutrient Requirements of Dogs and Cats (2006).
Our main calculator weaves calcium, raw meaty bone, Ca:P ratio, omega-3 and calories into a custom ration tailored to breed, age and activity.