What price triggers my trailing stop-loss on a percentage trailing stop?

How this is calculated

• For a long trade, the trailing stop price equals the highest price reached since entry multiplied by (1 minus your trailing stop percent). The stop only moves up as the stock makes new highs; it never moves down.
• For a short trade, the trailing stop price equals the lowest price reached since entry multiplied by (1 plus your trailing stop percent). The stop only moves down as the stock makes new lows; it never moves up.
• A percentage trailing stop is different from an ATR-based stop. This one recalculates off the running high or low price and a fixed percent; an ATR stop instead uses a fixed multiple of the stock's average true range. Use whichever matches your trading plan.
• This tool gives you the stop price to set right now, based on the extreme price you enter. As the stock makes a new high (long) or new low (short), come back and recalculate with the new extreme to see where your stop should move to.
• This tool does not place or manage the actual stop order with your broker. Some brokers offer a native trailing-stop order type that automates this for you; check how your broker's version handles gaps and after-hours moves before relying on it.