High happiness helps a city because:
  • more work gets done
  • it attracts more immigrants
  • it raises the maximum culture level
  • it prevents rebellions

Each turn, a city loses 1 happiness or gains 1/2 happiness until the happiness level reaches the target happiness. (Merchants may also raise happiness. Taxing will definitely lower it.)

The target happiness level can be calculated by starting with 100 and then adding these possible amounts:Then, subtract these possible amounts:

The happiness level can range from 0 to 100.