Here's why:

* Valence Electrons: Carbon has 4 valence electrons.

* Bonds: Carbon usually forms 4 covalent bonds, sharing one electron with each atom it bonds to.

* Formal Charge Calculation: Formal charge is calculated as:

* Formal Charge = (Valence Electrons) - (Non-bonding Electrons) - (1/2 * Bonding Electrons)

* In carbon's case, this would be 4 - 0 - (1/2 * 8) = 0

However, carbon can have a formal charge in certain situations, such as:

* Carbocations: These have a positive formal charge on carbon due to the loss of an electron.

* Carbanions: These have a negative formal charge on carbon due to the gain of an electron.

It's important to note that the formal charge is just a theoretical value, and the actual charge distribution in a molecule is more complex.