Investment fee impact calculator

The benchmark column is arithmetic, not a product: no fund has zero fees, so treat it as the ceiling every fee pulls you away from. The model assumes a constant return every month, percent-based fees only, no tax, no inflation, and no changes to the contribution. Real fee drag varies with what markets do; over a fixed horizon with a fixed rate it lands where the table says, and a 1 percent fee held for 20 years costs on the order of a sixth of the fee-free outcome, which is the whole point of the comparison.