Compare the surface area of two baking pans and estimate how much batter the target pan may need.
Area is only a starting point
Two pans with similar surface area can have different depths, edge shapes and heat behaviour. Do not overfill a pan. Leave the headroom required by the recipe, and expect baking time to change when batter depth changes.
Pan materials matter
Dark metal, light metal, glass, ceramic and silicone transfer and retain heat differently. Follow the pan manufacturer's instructions and use visual doneness cues.