Table VII-8a gives five equations for percentage of expected mature body weight from 8 weeks to one year, each keyed to an expected mature-weight band. PupCalendar inverts the relationship to make the rough adult-weight estimate. The plus or minus 15 percent range comes from the tool specification, not from a validated confidence interval in this publication.
Growth & age
Puppy Adult Weight Estimate
Choose the weight range your puppy may reach when fully grown, then use their age and current weight to see a rough estimate.
Puppy weight details
Use your puppy's age, current weight and likely adult size.
WEIGHT ESTIMATE
Adult-weight rough guide
Ready when you are.
Once the details are ready, your estimate and chart will appear here.
For general information only, not professional advice. Check the official sources below. Use your own judgement and speak to your vet before you act.
Based on official guidance
Calculated on your device
A starting point for your vet
HOW TO USE IT
Start with your details
Guess their weight when fully grown
Pick a broad range using your puppy's breed, parents' size or your vet's advice. This starting guess selects a growth curve. You can change it as your puppy grows.
Enter age and current weight
Enter a whole-week age from 8 to 52 and a weight greater than zero. Switch between kg and lb before entering the measurement.
Read the rough estimate
The result divides the current weight by the published age-and-size share. The range is 15% below to 15% above that result. It is a planning band, not a statistical confidence interval.
Read the source curve
The chart shows how the published percentage of expected adult weight changes by week for your chosen size group. The dot marks the percentage used for your estimate. It is not a forecast of your puppy's future weight. Share or print the result to discuss with your vet.
HOW IT WORKS
What shapes your result
FEDIAF's 2025 guidelines publish five equations for the percentage of expected mature body weight, each for an expected adult-weight group. They cover 8 weeks to one year. This tool turns that percentage into a share and divides the measured weight by it.
The 15% range comes from the PupCalendar tool specification. FEDIAF does not identify that range as an accuracy measure or confidence interval. Puppies of the same age and chosen adult-weight range can grow differently.
The chart plots the same group's published adult-weight percentage from 8 to 52 weeks. The selected dot marks the percentage used with the puppy's entered weight. Other points on the line are source percentages, not measured or predicted weights for this puppy. Regular weigh-ins and a vet's assessment still matter.
The chosen range describes likely adult weight, not your puppy's age or current weight. It may need changing as your puppy grows. If the age and current weight do not fit that source curve, the calculator explains the mismatch and withholds the estimate and chart instead of switching curves silently.
To catch typing mistakes, PupCalendar limits entered weights and adult-weight estimates to 200 kg, with the equivalent limit in lb. This is a calculator safeguard, not a source growth value or a veterinary weight threshold.
Read about our methodologyFAQ
Questions before
the next vet visit?
Bring your questions and this plan to your vet.
How accurate is this adult-weight estimate?
It is a rough guide from one current weight and a growth equation tied to the chosen adult-weight range. The 15% band is a planning convention, not a measured confidence interval. Your vet can assess growth using repeated measurements and your puppy's health.
Why do I need to choose an adult-weight range?
The published growth curves differ by expected adult weight. The tool cannot tell which curve fits from one current weight, so choose a broad likely range using breed, parents' size or your vet's advice. Your puppy's age and current weight then produce a more specific rough estimate. If they do not fit the selected curve, the tool withholds the result and asks you to check the details.
Why can I only enter 8 to 52 weeks?
The published equations used here are stated as valid from weaning age, 8 weeks, to one year. This calculator does not extend them before or after that span.
Does the chart show a puppy's future healthy weight?
No. It shows the published percentage of expected adult weight for the selected size group at each week. The dot is the percentage used in your estimate, not a recorded weight. The chart cannot account for individual growth, body condition, illness or sex. Regular weigh-ins and veterinary advice are more useful for checking growth.
What if the share is over 100% near one year?
The smallest group's published equation rises slightly above 100% near one year. The tool keeps the source value but withholds the unreliable estimate and chart. It does not silently cap the source curve.
Can I share or print the estimate?
Share puts the inputs in a URL fragment so the recipient can reproduce the result. Print includes the estimate, range, curve and limits. There is no calendar download for this tool.
Sources and checked dates
Each note explains what its source supports. Open the link to read the guidance yourself.
Explains that expected adult-size group affects the growth curve, individual growth varies, and a more reliable adult-weight assessment uses repeated measurements and veterinary context. Its charts do not supply the numeric percentages used by this tool.
