How many gallons fuel tank Saab 900?

It depends on the year. Fuel tank capacity for a specific year can be found in the Owners Manual under "Specifications". Some examples: 1983 900 (all models): 16.6 US gallons 1987 900 (all models): 16.6 US gallons I can't find a later Owners Manual in my file, but fuel capacity was increased in about 1988. I believe it went to 18.1 gallons.