The Math of Averaging Down — Why It's Risky

Averaging down (buying more as a position falls) lowers your average cost, which shrinks the bounce needed to reach breakeven — but in exchange, your capital at risk grows fast, and if the decline continues, your total loss grows with it. This simulator computes your average cost and breakeven exit price across a series of additional-buy scenarios, showing in numbers exactly how much of a bounce you'd need to get back to even.

For the math comparing averaging down and averaging up, see averaging down vs. averaging up. For principles that limit your downside, see setting your stop-loss rules. Repeating averaging down without a clear thesis can put your entire account at risk.

Worked Example

Example (illustrative numbers — not the actual price of any real stock): say you hold 10 shares at a 100,000-won average cost, the price has fallen to 80,000 won (a −20% loss), you have 3,000,000 won in cash available for more buys, ATR (volatility) is 5%, and you choose the "aggressive" strategy. Step 1 buys 5 shares (380,000 won) at 76,000 won (the −5% trigger), lowering your average to 92,000 won and cutting the breakeven bounce needed to 21.1%. Step 2 adds 14 shares (1,008,000 won) at 72,000 won, bringing the average to 82,345 won and the breakeven to 14.4%. Step 3 adds 22 shares (1,452,000 won) at 66,000 won, for a final average of 75,294 won and a 14.1% breakeven. Compared with the 25% bounce you'd have needed without averaging down, this 3-step plan cuts the required bounce by 43.6% — what the tool labels "capital efficiency."

What's Included and Excluded

Included: given your current average cost, shares held, cash available, and volatility (ATR), the tool computes up to 3 additional-buy trigger prices, buy quantities, and the resulting average cost and breakeven bounce for each step, under either an "aggressive" or "conservative" strategy. ATR is looked up automatically from recent price data and serves as a reference, not a substitute for checking the actual stock's volatility yourself.
Excluded: whether those trigger prices are actually fillable (liquidity, slippage), what happens once the full 3,000,000-won cash buffer is used up and the price keeps falling, trading commissions and taxes, any guarantee that the planned trigger prices are ever reached, and scenarios where the decline runs past the planned 3 steps.

Reading the Result

The "breakeven bounce" is the minimum rally needed to reach your new average cost if you execute the plan as shown — it is not a prediction that the price will actually bounce that much. A high "capital efficiency" score does not mean the strategy is favorable: it generally means more capital was committed at lower prices, so if the decline continues, your total loss can grow just as much. This calculator is not a signal to buy more — it only shows the arithmetic outcome of executing a specific plan.

Out-of-Range Inputs

An invalid ticker format shows "Invalid ticker format." Any other server-side issue shows as a temporary error — wait a moment and try again.

Assumptions and Limits

ATR (volatility) is computed from a lookup of recent prices; if that lookup fails or there isn't enough data, it silently falls back to a reference fixed value (3%), which can differ from the real stock's actual volatility. The aggressive strategy commits a larger share of capital earlier on smaller declines, while the conservative strategy waits for bigger declines before committing — so the same inputs can produce very different plans depending on which strategy you pick. This tool does not recommend buying any specific stock.