The Marteau Early 18th-Century Currency Converter is, if you want, a set of tools facilitating computations between early 18th-century monies. If you have a sum in one money we tell you how much that would have been in another. The tools operate on contemporary parity rates and evaluations of the circulating coinage – an orientation of greatest use wherever you had to compare prices and wages. Most of the 17th and 18th century currencies were based on non-decimal systems. We should make it easier to calculate with sums in these currencies.