The adult common frog has a body length of 6 to 9 centimetres (2.4 to 3.5 in) its back and flanks varying in colour from olive green to grey-brown, brown, olive brown, grey, yellowish and rufous.
However, it can lighten and darken its skin to match its surroundings.
Some individuals have more unusual colouration—both black and red individuals have been found in Scotland, and albino frogs have been found with yellow skin and red eyes.
During the mating season the male common frog tends to turn greyish-blue (see video below).
The average mass is 22.7 g (0.80 oz); the female is usually slightly larger than the male.

The flanks, limbs and backs are covered with irregular dark blotches and they usually sport a chevron-shaped spot on the back of their neck and a dark spot behind the eye.
Unlike other amphibians, common frogs generally lack a mid-dorsal band but, when they have one, it is comparatively faint.
In many countries moor frogs have a light dorsal band which easily distinguishes them from common frogs.

The underbelly is white or yellow (occasionally more orange in females) and can be speckled with brown or orange.
The eyes are brown with transparent horizontal pupils, and they have transparent inner eyelids to protect the eyes while underwater, as well as a 'mask' which covers the eyes and eardrums.
Although the common frog has long hind legs compared to the common toad, they are shorter than those of the agile frog with which it shares some of its range.
The longer hind legs and fainter colouration of the agile frog are the main features that distinguish the two species.

Males are distinguishable from females as they are smaller and have hard swellings, known as nuptial pads, on the first digits of the forelegs, used for gripping females during mating.
During the mating season males' throats often turn white, and their overall colour is generally light and greyish, whereas the female is browner, or even red.
The adult common frog has a body length of 6 to 9 centimetres (2.4 to 3.5 in) its back and flanks varying in colour from olive green to grey-brown, brown, olive brown, grey, yellowish and rufous. However, it can lighten and darken its skin to match its surroundings. Some individuals have more unusual colouration—both black and red individuals have been found in Scotland, and albino frogs have been found with yellow skin and red eyes. During the mating season the male common frog tends to turn greyish-blue (see video below). The average mass is 22.7 g (0.80 oz); the female is usually slightly larger than the male.
The flanks, limbs and backs are covered with irregular dark blotches and they usually sport a chevron-shaped spot on the back of their neck and a dark spot behind the eye. Unlike other amphibians, common frogs generally lack a mid-dorsal band but, when they have one, it is comparatively faint. In many countries moor frogs have a light dorsal band which easily distinguishes them from common frogs.
The underbelly is white or yellow (occasionally more orange in females) and can be speckled with brown or orange. The eyes are brown with transparent horizontal pupils, and they have transparent inner eyelids to protect the eyes while underwater, as well as a 'mask' which covers the eyes and eardrums. Although the common frog has long hind legs compared to the common toad, they are shorter than those of the agile frog with which it shares some of its range. The longer hind legs and fainter colouration of the agile frog are the main features that distinguish the two species.
Males are distinguishable from females as they are smaller and have hard swellings, known as nuptial pads, on the first digits of the forelegs, used for gripping females during mating. During the mating season males' throats often turn white, and their overall colour is generally light and greyish, whereas the female is browner, or even red.
Common frog