Guide 11.5
Intermediate, 4 min read. Checked with Scalpel 1.12.8 on .
In short
The Sizing tab sets your four buy presets, fired by Shift+1 to Shift+4 and the four buy buttons. Each preset is a kind and a number: a share count (Shares), a dollar clip (Notional), or a dollar risk sized off your stop (Risk (ATR), Risk (Low), Risk (Cents)). The defaults are 100, 250, 500 and 1,000 shares.
Your presets are the sizes you trade. With a risk kind, Scalpel works out the shares the instant you press, from the live ask and the stop, and rounds down so you never risk more than the number. Open Settings (Ctrl+,) and pick Sizing.
Each of the four rows has the same three parts:
| Part | What it does for your trading | Default | Allowed values |
|---|---|---|---|
| Shift+1 to Shift+4 | Which buy key and button the row drives. Rebind the keys on the Hotkeys tab. | Shift+1 to Shift+4 | Fixed labels |
| Kind (the dropdown) | How the number becomes a share count (table below). | Shares | Shares, Notional, Risk (ATR), Risk (Low), Risk (Cents) |
| Value | The number, in the unit shown after it: shares, $ / clip or $ risk. | 100, 250, 500, 1000 | Whole numbers up to 9,999,999 |
| Kind | The value is | Shares bought | Stop used | Best for |
|---|---|---|---|---|
| Shares | A share count | Exactly that many | ATR stop (Stops tab) | Simple, fixed clips on stocks in one price range |
| Notional | Dollars per clip | Dollars / ask, rounded down | ATR stop | The same dollar exposure on a $2 and a $20 stock |
| Risk (ATR) | Dollars of risk | Risk / ATR stop distance | 1.5 x ATR by default | Fixed risk with a stop that fits the stock's volatility |
| Risk (Low) | Dollars of risk | Risk / distance to the stop | Just under the lowest low of the last 20 one-minute bars | Fixed risk with a chart-based stop |
| Risk (Cents) | Dollars of risk | Risk / Risk (Cents) stop | Exactly N cents under the fill (30c by default) | The simplest fixed risk: you choose the stop |
| Preset | Shares | Dollars in the trade | Loss at the stop |
|---|---|---|---|
| Shares 500 | 500 | $2,855 | depends on the ATR stop |
| Notional 5000 | 875 | $4,996 | depends on the ATR stop |
| Risk (ATR) 100, ATR stop 18c | 555 | $3,169 | $99.90 |
| Risk (Cents) 100, 30c stop | 333 | $1,901 | $99.90 |
Fast small-cap scalping carries a significant risk of loss and is very difficult; most people who try it lose money. Small, fixed risk per trade is what keeps a learning curve survivable, so start with the smallest risk preset you can and size up only after weeks of consistent results in SIM.
A risk preset can ask for a lot of shares when the stop is tight. Your fat-finger and position caps still apply, and they refuse an oversized order rather than shrink it.
The presets do not have to share a kind. Some traders keep a share starter, a dollar clip for adds, and two fixed-risk keys:
Click Apply or press Enter to save. The buy buttons and the size line above each one update at once. The full guide to choosing sizes is guide 4.1, and fixed-risk trading is guide 4.2.