How big is a T. rex compared to a saltwater crocodile?
A T. rex measures 12 m (39.4 ft) end to end, and a saltwater crocodile measures 4.5 m (14.8 ft) end to end. A saltwater crocodile would have to grow by 167% to match a T. rex, which is 2.67 times its length. Take 2 saltwater crocodiles laid end to end and you reach 9 m (29.5 ft), still 3 m (9.84 ft) short of a T. rex; one more would overshoot by 1.5 m (4.92 ft). A T. rex is written in tens of metres and a saltwater crocodile in single metres, a whole band of scale apart.
| Object | Real size | Axis measured | What the figure covers |
|---|---|---|---|
| T. rex | 12 m 39.4 ft |
Length | Average Adult |
| Saltwater Crocodile | 4.5 m 14.8 ft |
Length | Average Male |
Both figures, T. rex and Saltwater Crocodile, come from the Size It Up measurement set, one real-world size and one measured axis per object, last checked in September 2026; outline provenance is listed on the sources page.
Why this one is hard to judge by eye
A T. rex is drawn about 2.67 times as wide as a saltwater crocodile as well as 2.67 times its length, so the area it takes in the frame grows faster than the figure anyone quotes. A T. rex sits in the range with no handy yardstick: too big to hold against anything you have carried, too small to need a horizon, so it and a saltwater crocodile end up filed under the same vague heading of very large. On the drawing above a T. rex is about 2.39 times as wide as it is tall and a saltwater crocodile about 5.23 times as wide as it is tall, so the two outlines fill the frame in ways that have nothing to do with the one axis being compared.
What each figure covers
T. rex. T. rex is quoted nose to tail. Specimens differ by metres, and the largest known individual is considerably longer than the average used here.
Saltwater Crocodile. Saltwater crocodiles are measured snout to tail tip. Records above six metres exist but are rare, and average adult males sit well below them.
A T. rex and a saltwater crocodile are both quoted as a length, which is what makes the ratio above a like-for-like figure.
What else is about that size?
Measured the same way, T. rex at 12 m sits within a tenth of Whale Shark at 12.1 m, X-wing Starfighter at 12.5 m and Modern London Double-Decker Bus at 10.9 m. Saltwater Crocodile at 4.5 m has Kyogre at 4.5 m, Land Rover Defender 110 at 4.6 m and London Black Cab at 4.6 m for company, within a tenth. Swapping any of those in for a T. rex would move its ratio to a saltwater crocodile by less than 10%.