# Settings: Trading

> Every option on Scalpel's Trading tab: SIM or LIVE, header P&L, buy and sell offsets and extended-hours fills for entries, with defaults and examples.

Source: https://scalpeltrade.com/guides/settings-trading
Guide 11.2, Settings reference. Intermediate, 5 min read.
Checked with Scalpel 1.12.8 on 2026-10-15. By Scalpel Team.

**In short:**

The Trading tab holds SIM or LIVE, where the header's LIVE P&L comes from, and how far your marketable limits reach: buys go out at the ask plus **Buy offset (c)** and bid exits at the bid minus **Sell offset (c)**, 10 cents each by default. **Extended-hours fills** is on, so LIVE entries can fill pre-market and after-hours; exits can always fill outside regular hours. Orders use IBKR SMART routing.

Every Scalpel order is a marketable limit: a limit order priced through the market so it fills now, with a cap on how far it can chase. This tab sets that cap. Open **Settings** (`Ctrl`+`,`) and pick **Trading**.

*Screenshot: The Trading tab at its defaults: SIM, the broker's P&L in the header, 10 cent offsets and extended-hours fills on.*

## Every option

| Option | What it does for your trading | Default | Allowed values | When to change it |
|---|---|---|---|---|
| **Mode** | SIM practises against the live book with a paper account; LIVE sends real orders to your IBKR account. | SIM | SIM or LIVE | Switch here or with the **MODE** picker in the header: both switch the running session as soon as you apply. |
| **Header P&L (LIVE)** | Whose profit and loss the header's DAILY P&L and UNREAL P&L show in LIVE. **Broker (IBKR)** is the whole account, including anything you trade in TWS. **Scalpel only** counts only the trades Scalpel placed. | Broker (IBKR) | Broker (IBKR) or Scalpel only | Pick **Scalpel only** if you also trade or hold longer-term positions in TWS and want the header to show just your scalping. SIM always shows the SIM ledger. |
| **Buy offset (c)** | How many cents above the ask your buy limit goes. The order fills at the best prices available up to that limit. | `10` | 0 to 9999, whole cents | Raise it on fast, thin stocks where 10c does not fill; lower it on slow, liquid ones to cap slippage. |
| **Sell offset (c)** | How many cents under the bid a bid exit goes: **Sell full**, **Sell half** and **Sell quarter** (`Ctrl`+`Z`, `X`, `C`, and the **Full**, **1/2**, **1/4** buttons). | `10` | 0 to 9999, whole cents | Raise it if your exits keep leaving shares behind in a fast drop. |
| **Extended-hours fills** | Lets LIVE entries fill outside the regular session, in the pre-market and after-hours. Exits (stops, targets, sells and **Flatten All**) can always fill outside regular hours, whatever this says. | On | On or off | Leave it on if you trade the pre-market. Turn it off only if you want LIVE buys held for the 09:30 open; your exits are not affected. SIM ignores it. |

**This can cost you money.**

Changing **Mode** to LIVE and clicking **Apply** (or pressing `Enter`) switches the running session straight away, exactly like the header's **MODE** picker: a toast and a "LIVE mode activated" callout, and the red **LIVE ORDERS** badge appears. From then on your keys send real orders. See [guide 6.2](https://scalpeltrade.com/guides/go-live).

**Note.**

There is no route setting: every LIVE order goes to Interactive Brokers with SMART routing, which picks the venue with the best price. That is what most active traders want.

There is no setting for shorting, options, futures or crypto, because Scalpel does not trade them: it is built for long-only scalping of US stocks, first of all in the pre-market. Every sell is capped to the shares you hold, so no key can put you short ([guide 7.3](https://scalpeltrade.com/guides/long-only)). Trading this way carries a significant risk of loss and is very difficult; most people who try it lose money. Stay in SIM until your results there are consistent, then start LIVE with small, fixed risk.

## How the offsets price your orders

The offset is a ceiling, not the price you pay. A buy with the ask at 5.71 and a 10c offset is a limit at 5.81. If 400 shares are offered at 5.71 and the rest at 5.72, you fill 400 at 5.71 and the rest at 5.72; you only reach 5.81 if the book is that thin.

| Ask / bid | Offset | Buy limit | Bid exit limit |
|---|---|---|---|
| 5.71 / 5.69 | 10c (default) | 5.81 | 5.59 |
| 5.71 / 5.69 | 3c | 5.74 | 5.66 |
| 12.40 / 12.36 | 25c | 12.65 | 12.11 |

- **Ask** and **mid** exits (`Ctrl`+`A`, `Ctrl`+`S`, **1/2 Ask**, **1/2 Mid**) ignore the sell offset: they sit at the ask or the mid and wait for a buyer.
- **Flatten All** (and `Esc`) prices its own exit: in LIVE it crosses about 1% through the price so the whole position clears in one order.
- **App-monitored stops** price their own exit too: in LIVE, a marketable limit sell 5 cents under the last trade. If price keeps falling past that limit, or the order sits unfilled for a few seconds, Scalpel cancels it and sends a new one under the latest price, crossing about 1% from the first retry. After 5 retries it leaves the order working and tells you to check it in TWS. None of this is a guaranteed fill: in a fast drop the price can run past any limit. Why Scalpel watches stops itself instead of resting them at the broker is in [guide 5.1](https://scalpeltrade.com/guides/how-stops-work).
- A sell or **Flatten All** while another exit is already working is never refused: the working sells are cancelled and one order replaces them for everything you still hold, at the lower of the prices.
- In SIM, a buy fills what the displayed book offers up to your limit, and the rest keeps working at the limit like a real order. See [guide 4.4](https://scalpeltrade.com/guides/entries-and-fills).

**Tip.**

The **Offset** steppers on the order bar change these same two settings, 10 cents per click (0 is the least). They are saved and apply on every desk, so a wide offset you set for one wild stock stays until you set it back.

## What can go wrong

- **A LIVE buy did not fill.** The price ran past ask plus your offset before the order reached the book. Raise **Buy offset (c)**, or press again. See [An order did not fill, or only part filled](https://scalpeltrade.com/guides/fix-order-not-filled).
- **An exit left shares behind.** Bid exits stop at bid minus the offset. Press the exit again, or use **Flatten All**, which crosses about 1% through the price and replaces any sell still working. See [guide 4.5](https://scalpeltrade.com/guides/scale-out-and-flatten).
- **The header P&L does not match your trades.** On **Broker (IBKR)**, it includes positions and trades from TWS. Switch to **Scalpel only**.
- **A pre-market LIVE buy sat unfilled.** **Extended-hours fills** is off, so IBKR is holding it for the open. Turn it back on.

## Questions

**What is a good buy offset for small caps?**

The default 10 cents fills most stocks between $1 and $20 in normal conditions. Fast movers with wide spreads may need 15 to 25 cents; a calm $3 stock may fill fine with 3 to 5. The offset is a ceiling: you still get the best prices on the book up to it.

**Does the sell offset apply to my stop?**

No. In LIVE an app-monitored stop sends a marketable limit 5 cents under the last trade, re-priced under the latest price if it does not fill, and Flatten All crosses about 1% through the price. The sell offset applies to the bid exits: Sell full, Sell half and Sell quarter.

**Can Scalpel trade pre-market?**

Yes. With Extended-hours fills on, LIVE entries can fill from the pre-market open at 04:00 to 20:00 New York time, as Interactive Brokers allows. Exits can always fill in those hours, even with the setting off. SIM fills in every session.

**Will my stop fill pre-market if Extended-hours fills is off?**

Yes. Every LIVE sell, including stop, target and Flatten All exits, carries the extended-hours flag. The setting only decides whether your buys can fill outside regular hours.

**What does Header P&L (LIVE) change?**

Only the DAILY P&L and UNREAL P&L figures in the header while you are in LIVE. Broker (IBKR) shows the whole account; Scalpel only shows the trades Scalpel placed.