犬の年齢計算機

犬種のサイズに基づいて犬の年齢を人間に相当する年数に変換。古い「×7」ルールより正確。完全クライアントサイド処理。

犬の年齢計算機について

犬の年齢に7を掛ける古いルールは、あまりにも単純です。実際には、犬は最初の2年間で急速に老化し、その速度は犬種のサイズによって大きく異なります。小型犬は長生きし、成犬後はゆっくりと老化しますが、大型犬と超大型犬はより速く老化し、寿命が短くなります。この計算機は、獣医学研究に基づく推定値を使用して、犬の実年齢をサイズカテゴリーに応じた人間に相当する年数に変換します。

機能

How to Use

  1. Enter your dog's age in years (0–30) and optionally months (0–11)
  2. Select your dog's size category: Small, Medium, Large, or Giant
  3. Click "Calculate Human Age" to see the converted age instantly
  4. Review the life stage badge (Puppy, Adolescent, Adult, Senior, or Geriatric)
  5. Read the tailored health tip for your dog's current life stage

Common Use Cases

Frequently Asked Questions

Why is the "× 7" rule not accurate for dog years?

The old "multiply by 7" rule is a rough estimate that ignores breed size differences. In reality, dogs age very rapidly in their first two years (reaching ~15 human years by age 1 and ~24 by age 2), and then aging slows differently based on size. Small dogs can live 15+ years, while giant breeds may only reach 8–10 years.

What size category should I choose for my mixed-breed dog?

Use your dog's adult weight to determine the size category: Small (under 20 lbs / 9 kg), Medium (20–50 lbs / 9–23 kg), Large (50–90 lbs / 23–41 kg), or Giant (over 90 lbs / 41 kg). If unsure, choose the category that matches your dog's weight range.

How accurate is this calculator compared to a veterinarian?

This calculator uses veterinary research-based estimates widely accepted by veterinarians. While it provides a good approximation, individual dogs may vary based on genetics, health, diet, and lifestyle. Always consult your vet for personalized health advice.

Can I use this for puppies under 1 year old?

Yes! Enter the months field to calculate fractional ages. A 6-month-old puppy is approximately equivalent to a 7–8-year-old human child, depending on size. This helps you understand developmental milestones and vaccination schedules.

What is the difference between senior and geriatric dogs?

Senior dogs are in the later stage of adulthood but still relatively healthy, typically entering this stage around 10 human-equivalent years for medium breeds. Geriatric dogs are very old, often requiring special medical attention, supplements, and diet adjustments, usually entering this stage around 15+ human-equivalent years.