Each month, your existing balance grows by the monthly rate (annual return ÷ 12), then your contribution is added on top. This compounds every period, so later contributions have less time to grow than earlier ones — the core trade-off of DCA vs. a lump sum. The return rate is a flat assumption; real markets, especially crypto, move in sharp swings rather than a smooth line, so treat this as a planning estimate, not a forecast. Read the full research breakdown →