While no city on average offers equal pay for the sexes, some fare much better than others, according to a study recently released by financial information company NerdWallet.

In the big-city category, it's probably not surprising that Washington, D.C. ranks at top, with a median female salary of $55,688, or 81.9 percent of the average salary of males in the nation's capital. After D.C., in order were San Francisco, San Jose, Austin and Dallas-Fort Worth.

In the medium-sized category, Durham-Chapel Hill (N.C.) topped the list, following by Oxnard (Calif.), Bridgeport (Conn.) and Stockton (Calif.)

In small cities, California's wine -growing capital of Napa stood out as best, with a whopping 91.6 percent parity rate, following by Hinesville-Fort Stewart (Ga.), Auburn-Opelika (Ala.), Charlottesville (Va.) and Santa Rosa (Calif.).