Whether the growth plates have closed is the usual checkpoint before jump training or long-distance running. Enter the projected adult weight and the current age in months, and this guide shows the size band, roughly when the growth plates close, and where the current age sits in that window.
Bigger dogs close later. Commonly cited ranges are 8 to 12 months for small dogs (under 22 lb), 10 to 14 months for medium dogs (22 to 55 lb) and 12 to 18 months for large dogs (55 lb and up), with giant breeds sometimes running later still. The guide picks the band from the projected adult weight and compares it with the current age. Guidance current as of October 2026.
There is no recognized table of closure ages by breed, so there is no breed selector. Closure varies a lot even within one size band and is confirmed only on radiographs, so treat the result as an approximate timing. The recommended neutering window, which also depends on sex, belongs to a separate tool. This tool is for reference only and does not replace veterinary care. Contact your veterinarian right away if you notice symptoms or suspect a problem.
Frequently Asked Questions
There is no recognized table of growth plate closure ages by breed. Instead of breed numbers with nothing behind them, the guide uses the projected adult weight to pick a size band and shows an approximate range.
Yes. Small dogs are shown around 8 to 12 months and medium dogs around 10 to 14 months. Large dogs close latest, around 12 to 18 months.
No. Closure is confirmed only on radiographs. Before starting serious jumping or long-distance running, talk it through with your veterinarian first.