English Mastiff Full Grown: Size & Weight
A full-grown English Mastiff weighs about 120–230 lb and stands roughly 27.5–30 in tall at the shoulder.
Have a English Mastiff puppy? Estimate its adult size
Built on the giant growth curve, clamped to the breed's range.
English Mastiff growth chart
How a giant-size dog like the English Mastiff fills out over its first months. Switch between percent of adult weight and pounds, and enter a weigh-in above to plot your puppy.
- English Mastiff
- Your puppy
Median curves computed from ~89,000 healthy dogs aged 2–24 months in the open Salt et al. 2017 dataset (PLOS ONE, CC BY 4.0), grouped into PuppySize's five size classes.
- English Mastiff · 120–230 lb
- Your puppy
Each shaded band shows the typical weight range at every age, with the line marking the middle of that range.
| Age | % of adult weight | Estimated weight |
|---|---|---|
| 2 months | 14.5% | 17–33 lb |
| 3 months | 26.5% | 32–61 lb |
| 4 months | 39.1% | 47–90 lb |
| 5 months | 50.5% | 61–116 lb |
| 6 months | 61.3% | 74–141 lb |
| 7 months | 71.7% | 86–165 lb |
| 8 months | 79.4% | 95–183 lb |
| 9 months | 84.6% | 102–195 lb |
| 10 months | 87.9% | 105–202 lb |
| 11 months | 91.2% | 109–210 lb |
| 12 months | 93.9% | 113–216 lb |
| 13 months | 95.7% | 115–220 lb |
| 14 months | 97.2% | 117–224 lb |
| 15 months | 97.2% | 117–224 lb |
| 16 months | 99.4% | 119–229 lb |
| 17 months | 99.4% | 119–229 lb |
| 18 months | 100% | 120–230 lb |
How confident is this estimate? Based on an official breed standard or cross-checked veterinary/registry sources.
About this breed's data: AKC (Mastiff) standard: males 30 in & up and 160-230 lb, females 27.5 in & up and 120-170 lb.
Sources: American Kennel Club, Salt et al. 2017 (PLOS ONE) growth data.
English Mastiff questions
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