Free Baking Pan Conversion calculator with clear step-by-step results.
Rectangular pans are interchangeable by base area, not by side length. The ratio of new area to original area is the factor to multiply every ingredient by, and because batter depth changes inversely with area the bake time is adjusted by a fractional power of that depth ratio.
Batter scale factor
Scale = (new length x new width) / (original length x original width)
Bake time
New time = original time x (1 / scale)^0.6
For a scale factor between about 0.7 and 1.4, yes. Beyond that, drop the temperature by 10-15 C for a deeper batter so the centre sets before the edges over-colour.
Heat reaches the centre by conduction, so time scales with depth faster than linearly but slower than the square. An exponent near 0.6 matches observed times for cakes and brownies better than a straight ratio.