You have a plan to put in a certain total over some years. Put it all in today (lump sum), or feed it in monthly? Under one smooth, constant return this calculator shows the pure math. The real answer depends on the market’s actual path — which is why we built the real thing on real fund history too.
Two honest caveats. (1) This assumes one smooth return, so “lump sum” gets the whole compounding runway. (2) In real markets, investing earlier has on average ended higher when markets trend up, but monthly investing smooths the luck of when you started. Neither is “right” for everyone — this is the shape of the math, not a recommendation.
Lump sum puts every dollar to work from day one — the maximum compounding time, and the maximum exposure if the market drops right after. Monthly investing spreads entries over time: some dollars catch the dips, some buy higher, and on a smooth upward line it ends behind lump sum. The gap is not about cleverness — it is simply time in the market.
Under a flat assumption the monthly plan “loses” by construction. In reality what matters is the path: a 2022-style drawdown right after a lump sum hurts; buying monthly through it helps. SeeFund’s in-tool DCA runs this against a fund’s actual daily history — including the fair money-weighted return — so the caveat here is exactly what the tool solves.
On average, in markets that trend up, earlier money (lump sum) has historically ended higher — but monthly investing smooths timing luck. The better fit depends on your situation.
This assumes one smooth return. Real markets zigzag, so real results differ — which is why SeeFund runs DCA on real fund history.
No — it is compounding arithmetic that shows the shape of the math, not what will happen.
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