Try it against the live book in SIM.Get Scalpel
, 4 min read
Most order entry asks you how many shares you want. That is the wrong question for a scalper. The right one is how much you are willing to lose if the stop gets hit, and the share count should fall out of that, at the moment you press the key.
Scalpel has four buy presets, each on its own key (Shift+1 to Shift+4 by default). Every preset is one of five kinds:
| Kind | What it means |
|---|---|
| Shares | A fixed share count. |
| Notional | A dollar clip. Shares are the clip divided by the price. |
| Risk (ATR) | A dollar risk. Shares are the risk divided by an ATR-based stop distance. |
| Risk (Low) | A dollar risk. The stop is the swing low on the chart. |
| Risk (Cents) | A dollar risk. The stop sits a fixed number of cents under your fill. |
With any risk preset, the share count is worked out the instant you fire, from the live price and the stop distance. A $50 preset always puts exactly $50 at risk to the stop, whether the stock is $2 or $12.
If you want every trade to risk the same dollars with the same stop logic, use Risk (Cents). Set your four buttons to, say, $500, $1,000, $1,500 and $2,000. With the default 30 cent stop, the $1,000 button buys 3,333 shares (1,000 divided by 0.30), and the stop is armed 30 cents under the fill.
A Stop stepper sits next to the buttons on the order bar. Nudge it 5 cents at a time for the stock in front of you: tighter on a $2 runner, wider on a $12 one. The note above each button shows the dollar size that press would buy, so you never fire blind.
Sizing by risk can produce big share counts on tight stops. That is what the hard guards are for:
Set them once in Settings, under Risk, and every preset respects them.
Fixed share counts quietly change your risk from trade to trade. A 1,000 share clip with a 10 cent stop risks $100; the same clip on a stock that needs a 40 cent stop risks $400. Sizing from the stop keeps every trade at the risk you chose, which makes your R numbers in Analytics mean something.
Start in SIM, fire a few presets against the live book, and watch the share count change with the stop.