Assign each bill a distinct fold and practice until the shapes feel automatic. One common approach keeps the one-dollar bill flat, folds the five-dollar bill once, and creases the twenty into quarters. The exact pattern matters less than using the same one every time.
Fold bills immediately after identifying them. A pile of unfolded cash quickly turns into a guessing game, so take a moment right after a transaction to sort notes into separate wallet compartments by shape.
Folding is free, private, and available whenever you don't want to pull out your phone. Its main limitation is that you must know the value before you fold, so pair this method with a camera app or a trusted cashier for new or damaged bills.


