The basic DPS formula in Infectonator Survivors and in most games, without range taken into account, can be calculated by dividing the total damage that can be done prior to reloading by the total time a magazine lasts plus the time to reload. This can be expressed as:

Total Damage Per Magazine / Total Time Until Next Magazine = Damage Per Second

or

(Damage * Ammo) / (Ammo / Fire Rate + Reload) = DPS

For example, the Glock in-game does 10 damage per round and has 15 rounds in it's magazine which means it does 150 damage before reloading. The 15 rounds are ejected at a rate of 2.5 per second making the entire magazine last 6 seconds. The total time before being able to fire again is 7 seconds due to the reload on the Glock being 1 second. So the total damage that can be done before reloading (150 damage) divided by the total time taken before starting another magazine (7 seconds) means the average sustained DPS for a Glock is 21.4 rounded to the nearest tenth. The formula for the example is as followed:

(10 * 15) / (15 / 2.5 + 1) = ~21.4