Average-Down Calculator
New cost basis & break-even price after averaging down (fees included)
Current position
Market value CNY 10,000.00
Averaging-down plan
New cost basis
9.25 CNY
Fees & methodology
New cost = (original position cost + total averaging-down outlay) ÷ total shares, where the outlay includes buy-side commission and transfer fee (matching the broker's cost-basis convention). The break-even price includes sell-side commission, stamp tax (0.05%, sell only) and transfer fee, rounded up to the cent.
Compare averaging-down scenarios
| Plan | New cost | Break-even | Gain needed | Capital |
|---|---|---|---|---|
| No averaging down | 10.00 | 10.02 | +17.88% | — |
| Buy 100 shares | 9.87 | 9.88 | +16.24% | CNY 855.01 |
| Buy 500 shares | 9.50 | 9.51 | +11.88% | CNY 4,255.04 |
| Buy 1,000 shares | 9.25 | 9.26 | +8.94% | CNY 8,505.09 |
| Buy 2,000 shares | 9.00 | 9.01 | +6.00% | CNY 17,005.17 |
The table compares the math of different position sizes only — it is not investment advice.
What is the break-even price, and how does it differ from cost basis?
The break-even price (also the "unstuck" price) is the sell price at which you recover your entire outlay exactly. It is not your cost basis: cost basis is the average price you paid, while the break-even price must also cover sell-side commission, stamp tax and transfer fee, so it starts slightly above cost (10 CNY cost → about 10.02). More importantly it is a moving line: buying more at a lower price pulls it down — add enough at 8.5 and the line can drop from 10.02 to 9.30. The "reverse" mode answers exactly this: how many shares to buy to move that line to a chosen level.
How is the new cost basis after averaging down calculated?
The core formula: new cost = (original position cost + total averaging-down outlay) ÷ total shares. The outlay includes not just the market value bought but also buy-side commission and transfer fee — matching the cost basis your broker app displays. Example: holding 1000 shares at 10 CNY, buy 1000 more at 8.5 → new cost = (10000 + 8500) ÷ 2000 = 9.25 CNY.
Why is the break-even price higher than cost basis?
Because selling incurs three fees: commission (charged on both sides, with a 5 CNY minimum at most brokers), stamp tax (sell side only, currently 0.05%), and transfer fee (both sides, 0.001%). Only a sell price covering "position cost + all sell fees" is a true break-even, so the precise break-even always sits slightly above the diluted cost. This tool includes all three fees and rounds up to the cent — sell at the displayed price and you break even exactly, or marginally better.
How do I use reverse mode?
Switch to the "Reverse: how many shares" tab and enter your target break-even price (e.g. "if it gets back to 9.3 I'm out"). The tool tries from the minimum lot (100 shares) up and returns the exact share count and the cash required. If your target is below the buy price, there is mathematically no solution — averaging down pulls cost toward the buy price, never below it — and the tool will say so outright.
Should I set the fee rates?
Strongly recommended. Click "⚙ Rates" in the top right and enter your broker's actual commission rate (in your account agreement or the app's rate inquiry page). If your account has no 5 CNY minimum ("minimum-free"), remember to uncheck the minimum-commission box — on small trades the difference can reach several percentage points. Set once, applies site-wide; data stays on your phone, nothing is uploaded.