Match your goal: fresh pepper flavor (try serrano, poblano, or Anaheim) vs. heat-only (cayenne or red pepper flakes).
Use the ratio in the table as your starting point; for hotter options, reduce quantity first.
If you’re using a fresh pepper, chop finely; for powder/flakes, sprinkle gradually so you don’t overshoot heat.
Adjust heat and balance: remove seeds for less heat, and add a small splash of acid (lime/vinegar) if the swap tastes flat.
Taste and refine—especially for salsas and dips where jalapeño character is obvious.