Paste an ingredient list, set the servings the recipe makes and the servings actually needed, and every quantity is rescaled in one pass.
Lines that do not start with a number are passed through unchanged, so headings and notes can stay in the list.
Scaling a recipe is a single multiplication: every quantity is multiplied by the target servings divided by the original servings. This scaler reads the quantity at the start of each line — whole numbers, decimals, fractions such as 1/2 and mixed numbers such as 1 1/2 — scales it, and writes the results back in the same style, using simple fractions where they fit. Cooking times and pan sizes do not scale in the same way: a doubled batch in the same pan usually needs a similar temperature and only a modestly longer time, checked by doneness rather than the clock.
Does cooking time double when a recipe doubles? No. Time depends mostly on thickness and pan size, not total volume. Keep the temperature the same, start checking at the original time, and expect a somewhat longer finish for a deeper or fuller pan.
What about ingredients listed without a number, like 'salt to taste'? Those lines are left unchanged, which is the right treatment — seasonings to taste do not scale with servings, and yeast and baking powder in very large batches often need less than a strictly proportional increase.