All five species of tody (Todus) are very small, chunky, short-tailed birds, with green upperparts, a red throat, and a long, flattened bill. The Broad-billed Tody is grayish white, with a yellow tinge to the breast and belly, pinkish red flanks, and yellow lower belly and undertail coverts.
The Broad-billed Tody is similar to the Narrow-billed Tody (Todus angustrirostris), Cuban Tody (Todus multicolor), Jamaican Tody (Todus todus), and Puerto Rican Tody (Todus mexicanus). Of these species, however, the Broad-billed Tody overlaps geographically only with the Narrow-billed Tody. Narrow-billed Tody usually is whiter on the breast, and the mandible usually has a dusky tip; Broad-billed Tody is tinged with yellow on the breast, and the mandible is entirely red. The two species also differ by voice, which often is the best way of differentiating them in the field.
The Broad-Billed Tody is the largest (ca 6-7 g) of all five tody species and is more stout than the Narrow-billed Tody (Kepler 1977). The bill is approximately twice the width of the Narrow-billed Tody.
The following detailed description is based on Ridgway (1914):
Adult: Sexes similar. Upperparts plain bright green. Malars dull white, becoming gray posteriorly. Chin dull white. Throat geranium red; the throat feathers are narrowly tipped with white. Lower neck dull white. Breast and belly whitish or pale sulphur yellow, the breast usually with a pale yellowish gray wash, sometimes also tinged with pink. Flanks geranium pink. Undertail coverts bright sulphur yellow. Axillars and underwing coverts light sulphur yellow.
"Young:" Upperparts as in adult. Malar grayish buff or dull yellowish buff. Chin grayish. Throat pale yellowish buff, slightly tinged with red. Remaining underparts yellowish white, breast broadly streaked with dusky gray. Undertail coverts more yellowish, tinged with green.
Very little information about molt in Broad-billed Tody, but primary molt is initiated in early July, overlapping with the end of breeding (A. Dhondt, personal communications).
Data from Ridgway (1914):
Iris: brown
Bill: maxilla black ; mandible red
| wing length | tail length | bill length | bill width | tarsus | n | |
| (exposed culmen) | (at nostrils) | |||||
| male | mean 50 | mean 35.4 | mean 20.5 | mean 5.8 | mean 13.8 | 10 |
| range 47.5-53 | range 33-37 | range 18.5-22 | range 5.5-6 | range 13-14.5 | ||
| female | mean 49.2 | mean 35.5 | mean 19.7 | mean 5.7 | mean 13.8 | 10 |
| range 47-51.51.5 | range 33.5-38 | range 18-21 | range 5.5-6 | range 13-14.5 |
Mass: mean 8.7 g ± 0.7 (range 7.8-10.2 g, n=28, sex unknown; Arendt et al. 2004).