Calw or Kalw, a town of Germany, in the kingdom of Württemberg, on the Nagold, 34 m. S.W. of Stuttgart by rail. Pop. (1905), 4943. It contains a Protestant and a Roman Catholic Church, two schools, missionary institution, and a fine public library. The industries include spinning and weaving operations in wool and cotton. Carpets, cigars and leather are also manufactured. The timber trade, chiefly with the Netherlands, is important. The place is in favour as a health resort.
The name of Calw appears first in 1037. In the middle ages the town was under the dominion of a powerful family of counts, whose possessions finally passed to Württemberg in 1345. In 1634 the town was taken by the Bavarians, and in 1692 by the French.