Dollar cost averaging vs lump sum calculator

On average, investing the lump sum all at once wins. Markets rise more often than they fall, so the sooner your money is invested, the longer it compounds. Vanguard's well-known study found a lump sum beat dollar-cost averaging (DCA) roughly two-thirds of the time, by about 1–2% on average over the first year. DCA only comes out ahead when the market is flat or falls during the period you're spreading your money in — which is exactly when it feels hardest to invest a big sum at once.

Dollar-cost averaging (DCA) means investing a fixed amount at regular intervals — say, one-twelfth of a windfall each month for a year — instead of all at once. By spreading purchases over time you buy more units when prices are low and fewer when they're high, so your average cost smooths out. It doesn't maximize expected return; it trades a bit of expected growth for less exposure to bad timing and the regret of investing everything the day before a drop.

The landmark analysis is Vanguard's "Dollar-cost averaging just means taking risk later." Looking across decades of US, UK and Australian data, investing a lump sum immediately outperformed a 12-month DCA approach about two-thirds of the time, with average outperformance around 1.5–2% over the first year. The reason is simple: markets spend most of their time rising, so cash sitting on the sidelines usually misses out. The longer the DCA window, the bigger the average drag.

DCA is more about behaviour than maths. It makes sense when (1) investing everything at once would keep you up at night, and the alternative is not investing at all; (2) you're investing near retirement, when a bad first year hurts more (see sequence of returns risk); or (3) you genuinely think markets are stretched and want to hedge your timing. The right plan is the one you'll actually stick with — a slightly lower expected return you can live with beats an optimal one you abandon.

Statistically, shorter is better — every extra month of sidelined cash adds expected drag. If you're going to DCA, common windows are 3 to 12 months; beyond a year the cost of waiting usually outweighs the timing benefit. A good middle ground for a nervous investor is to deploy over a few months rather than a few years. This calculator lets you test how the window length changes the trade-off.

It reduces timing risk — the chance of putting everything in right before a downturn — and the regret that comes with it. But it doesn't reduce the long-run risk of being invested, and it slightly lowers your expected return because your money spends less time in the market. Think of it as buying insurance against a bad entry point: valuable for peace of mind, but with a small premium you pay in expected growth.

No — and this is a common mix-up. Investing money as you earn it (from each paycheque) isn't dollar-cost averaging; it's simply investing as soon as you have cash, which is the optimal thing to do. True DCA only applies when you already have a lump sum and choose to feed it in gradually rather than invest it now. If you have the money available, the lump-sum-versus-DCA question is the one this tool answers.

It still usually favours the lump sum. All-time highs are far more common than they feel — a rising market makes new highs routinely, and on any given day the market is often near a peak. Historically, investing at all-time highs has produced returns very similar to investing on any other day, because markets tend to keep climbing over time. Waiting for a dip means sitting in cash that, on average, earns less than the market you're trying to time.

In a high-interest savings account, money-market fund, or cashable GIC — somewhere safe and liquid that still earns a yield. The interest your sidelined cash earns directly improves DCA's odds: when cash yields are high, the gap between the two strategies narrows, as the break-even in this calculator shows. Just don't let "waiting to invest" quietly turn into "never investing" — set a fixed schedule and automate it.

No. It compares pre-tax outcomes over the deployment window. In a registered account (TFSA, RRSP, FHSA) there's no tax friction either way, so the comparison is clean. In a taxable account, spreading purchases creates more buy lots to track for adjusted cost base, and any interest on sidelined cash is taxable. Those are second-order effects, but worth knowing before you choose.

No — it's an educational model. It assumes a steady market path over your deployment window and a constant cash yield; real markets move in jumps, and the actual winner depends on the path prices happen to take. Use it to understand the trade-off and to pressure-test your own assumptions, not as a recommendation. For a decision involving a large windfall, a fee-for-service advisor can help you weigh the maths against your temperament.