Do you know of a currency calculator that uses the exchange rate at an earlier date?

I buy a lot of books from overseas for my work. I can claim these books on my tax but the purchase price is often in US$ or British pounds (can’t find the symbol). I am in Australia and so need to calculate the AU$ value at the time I bought the book.

I can find calculators that will convert the value of currency today but not retrospectively. Does anyone know of a site where I can put in a date and a US$ value or other currency and it will calculate the value based on the exchange rate on that earlier date?