A standard concert pedal harp has 47 strings.
The modern concert harp, also called the double-action pedal harp, uses strings of different lengths and thicknesses to cover a wide range of pitches. Its seven pedals correspond to the seven note names: C, D, E, F, G, A, and B.
Each pedal has three positions, allowing the harpist to set every note of that name as flat, natural, or sharp. This system lets the instrument play in all major and minor keys while the strings remain arranged in a single diatonic sequence.
The number 47 applies to the full-size orchestral pedal harp. Smaller lever harps may have substantially fewer strings, so the terms “harp” and “concert harp” should not be treated as interchangeable. The harp’s lowest strings are generally wound with metal, while its higher strings are commonly made from gut or synthetic materials.