Both are top-level open-wheel single-seater series, but they differ in philosophy:
- Cars — In F1, every team designs and builds its own car, so machinery is a huge performance variable and budgets are enormous. IndyCar uses a spec car — a common Dallara chassis and a control-spec twin-turbo V6 engine (from Honda or Chevrolet) — so the field is far closer and cheaper to run.
- Circuits — F1 races almost entirely on road and street circuits around the world. IndyCar mixes ovals, road courses and street circuits, and oval racing gives it a very different, high-speed pack character.
- Home & identity — F1 is a global championship with a worldwide calendar; IndyCar is US-centric, and its crown-jewel event is the Indianapolis 500.
- Racing feel — F1 emphasises technology, aerodynamics and strategy; IndyCar's parity produces closer wheel-to-wheel racing and unpredictable results.
Neither is simply "better" — they reward different things. Compare the grids on our F1 and IndyCar pages.