Adult iguanas can range from about 7 inches for the smallest species up to around 6–7 feet long for the largest, with big species often weighing 10–20 pounds or more.

Quick Scoop

Typical pet iguana (green iguana)

  • Green iguanas, the classic pet species, commonly reach 5–6 feet from nose to tail when fully grown.
  • A healthy adult male can weigh roughly 10–20 pounds, with some large males going even heavier.
  • Females are usually smaller, more in the 3–5 foot range and lighter in weight.

Overall size range by species

  • Across all iguana species, adults can be as small as about 7–12 inches and under 0.5 pounds for the tiniest types.
  • Larger species like green iguanas, Cuban rock iguanas, and related giants can reach 5–7 feet and 15+ pounds, with some blue iguanas reported over 30 pounds.

Quick HTML size table

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Iguana type Typical adult length Typical adult weight
Small species (desert / Fiji banded) 7–12 inches Under 0.5 lb
Common pet green iguana 5–6 feet, some up to ~7 feet About 10–20 lb, sometimes 25+ lb
Large rock/blue iguanas Up to ~5–7 feet Roughly 15–30+ lb reported

In forum-style discussions, people are often surprised that the “little” iguana they brought home can end up roughly as long as a person and heavier than a small dog.

If you’re thinking of getting one

  • Expect a full-sized enclosure big enough for a 5–6 foot, tree-climbing lizard, not a small aquarium.
  • Their growth is fast in the first few years, so planning for adult size from day one is essential.

TL;DR: Most pet green iguanas end up around 5–6 feet long and 10–20 pounds, while the smallest iguanas stay under a foot and the very largest can approach or exceed 7 feet and 25–30+ pounds.

Information gathered from public forums or data available on the internet and portrayed here.