Estimate the electrical panel amperage your home needs.
Residential service sizing uses the optional method in NEC 220.82, which recognises that no house runs everything at once. General lighting and receptacles are counted at 3 VA per square foot, the two required kitchen small-appliance circuits at 1,500 VA each and the laundry circuit at 1,500 VA; fixed appliances go in at nameplate. The first 10,000 VA of that total counts at 100% and everything above it at just 40%. Heating or cooling is added afterwards at full value, and only the larger of the two, since they never run together. Dividing by 240 V gives the demand in amps, and the panel is then chosen a stock size above that with roughly 15% headroom — worth having, because an EV charger or a heat pump is the usual next addition.
Electrical Panel Size
Non-HVAC load = 3 VA/sq ft + 3000 + 1500 + appliance nameplates; demand = first 10,000 VA at 100% + remainder at 40% + larger of heating or cooling; amps = demand / 240
A planning estimate, not a load calculation of record. Service sizing must be performed to the NEC or local wiring rules by a licensed electrician, and a service change requires utility coordination and inspection.
For a small, gas-heated home with no EV, often yes. Add electric heating, an electric range and a car charger and the calculated demand usually pushes past 100 A, which is why 200 A is now the default on new builds.
They are separate problems. Running out of breaker spaces can be solved with tandem breakers or a subpanel; running out of amps means a service upgrade involving the utility.