Electronics Handbook/Components/Capacitors/Parallel Connection

Capacitor connected in parallel
Two or more capacitors can be connected in parallel to increse the total capacitance
 * $$C_t = C_1 + C_2 + .... + C_n$$

Two of the same value

 * $$\frac{1}{C_t} = \frac{1}{C} + \frac{1}{C} = \frac{1}{2C}$$