Do I need 100 or 200 amp service?

You need 200 amp service if your future includes an EV charger, heat pump, electric range, or a shop. You are fine on 100 amps in a small to mid-size home where gas covers heating, water, and cooking.

The deciding document is an NEC 220 load calculation, not the size of the house or the number of breakers. Panels full of breakers routinely calculate under 100 amps because loads are diverse.

The difference between the services is capacity only; 100 amps is not less safe.

Sitting at the boundary, choose by trajectory: electrification only ever adds load, and doing the upgrade once, ahead of need, is cheaper than doing it during an emergency panel swap.

The service line size calculator shows what conductors either choice requires.