Generally, look for 10,000+ BTUs per burner per hour, as that equates to the output of a burner on an average home stove. You can find camping stoves that range fairly below and above that, but know that it’s how you will be using the stove that matters. Fewer BTUs isn’t inherently bad, and in some cases can be desired (e.g., if you just want a low or slow simmer) and more BTUs isn’t always better (e.g., if you’re not doing anything fancy and want your fuel to last).