If you are making a planned journey, you can check with the ZVV website.
Below the times it will tell you the tariff level and the zones which are involved. As zone 10 is so large, it's classified as two zones. For example:
Within zone 10 to the HB:

Tarifstufe*: 2; Zonen*: 10;
or to the airport:

Tarifstufe*: 3; Zonen*: 10; 21;
There are some other anomalies involving crossing out and into zones, and for this this there's a triangle button on ticket machines. For example: Zurich to Stettbach is technically all zone 21, but to generally do the journey you must go through 10. Pressing the triangle will correct this and charge you appropriately.