When is a Neapolitan Mastiff fully grown?

Most Neapolitan Mastiffs reach their maximum height by 12 months, but continue to fill out with muscle mass until about 18 months of age.

Puppy Predictor

Neapolitan Mastiff Size Calculator

How big will my Neapolitan Mastiff get? Predict adult weight and track your puppy's development.

Puppy Weight Forecaster

Predicting the growth of your Neapolitan Mastiff

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Dog's Name

Breed

Gender

MaleFemale

Age

Current Weight (lbs)

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Personalize this chart

Enter age and weight to see your dog's unique trajectory.

Breed Standard

Projection

Current

Breed Overview

About the Neapolitan Mastiff

Loyal, observant, and dignified

Group

Working

Size Category

Giant

Lifespan

7-9 years

Full Maturity

24 months

Temperament Traits

DignifiedProtectiveStubbornLoyalCalmTrainable

Growth & Height Benchmarks

Expected Adult Weight

110-150lbs

Typical Male

110-150 lbs

26-31" tall

Typical Female

110-150 lbs

24-29" tall

How the Neapolitan Mastiff Calculator Works

High-Sensitivity Dynamic Modeling

We use a proprietary High-Sensitivity Dynamic Model calibrated specifically for Neapolitan Mastiff development. This accounts for the biological reality that growth velocity decelerates sharply as a puppy matures, ensuring pinpoint accuracy for both 8-week-old puppies and older teenagers.

Maturity Window Calibration

A Neapolitan Mastiff typically reaches its full skeletal structure around 24 months. Our algorithm applies a specific maturity multiplier that adjusts the projection as your puppy approaches this target window.

Standard Deviation Check

Every projection is cross-referenced against the Neapolitan Mastiff breed standard (110–150 lbs). While estimates can begin at 6 weeks, data collected after the 12-week mark provides the highest statistical confidence.

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