Trailing Stop Calculator
Enter your entry price, the peak the stock has reached, and your trail %. We'll show where the stop sits, how much profit is locked in, and how far the current price is above it.
Setting trailing stops by hand on every position? Fuselit runs trailing stops and rebuy logic automatically on your Alpaca account.
Try Fuselit free →How trailing stops work
A trailing stop is a stop-loss order that automatically follows the price up, never down. You set it as a fixed percentage (or fixed dollar distance) below the highest price reached since entry. Each time the stock makes a new high, the stop ratchets up by the same percentage. If the price reverses, the stop stays where it is — and eventually triggers if the price falls back to it.
The mechanic is simple: trail_stop = peak × (1 − trail%/100). It's the cleanest way to let winners run while protecting accumulated profit. The trade-off is that a tight trail exits you on normal pullbacks, while a wide trail gives back more of the gain before triggering. Most traders match the trail width to the stock's typical daily range — often via ATR.
Frequently asked questions
How do you calculate a trailing stop loss?
Multiply the highest price the stock has reached since you entered (the peak) by (1 − trail_percent/100). The result is your current trailing stop level. As the peak rises, the stop ratchets up with it; if price falls, the stop stays put.
What is a good trailing stop percentage?
It depends on the stock's volatility. For large-cap, low-volatility names, 5–10% is common. For volatile growth stocks, 15–25% prevents normal noise from stopping you out. A common rule is to set the trail at 2–3× the stock's average true range (ATR) over the prior 14 days.
What's the difference between a trailing stop and an ATR trailing stop?
A percentage trailing stop trails by a fixed percentage of the peak price. An ATR trailing stop trails by a multiple of the stock's average true range — it adapts to changing volatility. ATR stops are tighter in calm markets and wider in volatile ones, which often reduces premature exits.
When should a trailing stop trigger?
The trailing stop triggers when the market price touches or crosses below the stop level (for a long position). Some brokers fill at the stop price as a market order, others use a stop-limit. Always check how your broker handles fills, especially in fast-moving markets.