Stop-Loss Placement and Risk per Trade, in Plain Numbers
Stop-loss placement decides how big a position you can take for the same risk per trade. See the math for stop distance, fees, gaps and a placement checklist.
Key takeaways
- Fix the dollar risk, then place the stop, then size: with $100 at risk, a 2% stop allows $4,764 of ETH and a 15% stop $663.
- Place the stop where the trade idea is wrong and outside normal daily swings, not at a distance chosen to fit a position.
- A gap can more than double the loss: a fill at $1,780 on a $1,900 stop turns a planned $100 loss into $217.65.
- Widening a stop after entry is a hidden risk increase: moving it from $1,900 to $1,800 lifts the planned loss to $198.04.
On this page
- What does a stop-loss actually do?
- Risk per trade: fix the dollars first
- Worked example: one risk budget, four stop placements
- Where to put the stop: invalidation first, noise second
- When the stop doesn’t fill at the stop price
- Moving a stop: a one-way rule
- Common stop-loss mistakes
- The bottom line
- Frequently asked questions
- Sources
Note: This article explains the arithmetic of stops and risk; it is not a suggestion to trade. The SEC warns that day traders typically suffer severe financial losses in their first months of trading.
What does a stop-loss actually do?
A stop-loss is an instruction to exit a position once the price reaches a level you chose in advance, the stop price. It turns an open-ended loss into a planned one, at least on paper.
On paper, because a standard stop order becomes an order to trade at the next available price once the stop is reached. In a fast market, the fill can be significantly worse than the stop price. A stop-limit order sets a limit on the fill price, but there is no guarantee it executes, so the position can stay open while the price keeps falling. A sharp, brief drop can also trigger a stop just before the price recovers. Crypto trades around the clock and is exposed to sudden flash crashes, so these risks never go off duty.
Risk per trade: fix the dollars first
Risk per trade is the amount you plan to lose if the stop is hit: account value × risk percentage. On a $10,000 account at 1%, that is $100. The 1% risk rule explains why that percentage is kept small.
The order of operations matters. Fix the dollar risk, place the stop where it belongs on the chart, and only then calculate the position size. Picking the size first and squeezing the stop to fit is how stops end up at prices the market reaches on an ordinary day.
Worked example: one risk budget, four stop placements
Suppose you plan a hypothetical ETH trade with an entry at $2,000 and $100 of risk. Fees are 0.1% round trip, 0.05% on each side, and they belong in the risk per unit: for a $1,900 stop, that is $100 + $1.00 + $0.95 = $101.95 per ETH. Maker, taker and spread costs explains where those fees come from.
| Stop price | Distance | Risk per ETH | Position size | Position value | Share of account |
|---|---|---|---|---|---|
| $1,960 | 2% | $41.98 | 2.3821 ETH | $4,764.17 | 47.64% |
| $1,900 | 5% | $101.95 | 0.9809 ETH | $1,961.75 | 19.62% |
| $1,800 | 10% | $201.90 | 0.4953 ETH | $990.59 | 9.91% |
| $1,700 | 15% | $301.85 | 0.3313 ETH | $662.58 | 6.63% |
Every row loses the same $100 if the stop fills at its price. What changes is the size: a stop 7.5 times further away buys a position about one-seventh as large. On the tightest stop, fees are 4.72% of the risk per unit, so leaving them out would quietly push the loss above $100.
- Fix risk per trade in dollars: $10,000 × 1% = $100
- Put the stop where the trade idea is proven wrong
- Check that the stop sits outside normal daily swings
- Add fees and a slippage allowance to risk per unit
- Units = $100 ÷ risk per unit
- Enter with the stop live, and never widen it
Where to put the stop: invalidation first, noise second
Start from where the idea is wrong
A stop belongs at the price that would show your reason for the trade was wrong, for example just beyond a level you expected to hold. A round number or a fixed percentage has no connection to what the market is doing.
Then check it against normal daily swings
A stop inside the asset’s ordinary daily range can be hit by noise alone. A simple check is the average daily range: the average of each day’s high minus its low over recent days. Suppose five hypothetical days for ETH near $2,000 had ranges of $70, $82, $64, $90 and $74. The average is $76, or 3.8% of the price, so a 2% stop would sit well inside a normal day.
A stop at twice the average range would be $152 below entry, at $1,848, or 7.6% away. With fees, the risk per ETH is $153.92, and $100 of risk buys 0.6497 ETH, a $1,299.34 position. The stop is wider, so the position is smaller, and the dollar risk hasn’t changed.
When the stop doesn’t fill at the stop price
Take the 5% row: 0.9809 ETH with a stop at $1,900. If the price gaps down and the stop fills at $1,780, which is 6.32% below the stop, the loss becomes $217.65 including fees, or 2.18% of the account. The planned 1% loss more than doubled without any error in the math.
You can build in a cushion by adding a slippage allowance to the risk per unit. Allowing 0.5% of the stop price, or $9.50, raises the risk per ETH to $111.45 and cuts the position to 0.8973 ETH, worth $1,794.53. If the stop fills cleanly, the loss is $91.48; if it slips by up to $9.50 per ETH, you still stay within the $100 budget. No allowance covers every gap, which is why the risk percentage itself stays small.
Moving a stop: a one-way rule
Widening a stop after entry is a risk increase in disguise. Moving the $1,900 stop to $1,800 on the same 0.9809 ETH raises the planned loss from $100 to $198.04, roughly 2% of the account, without anyone recalculating the size.
Tightening works the other way. Moving the stop up to the entry price cuts the planned loss to the fees, about $1.96, but puts the stop closer to the current price, where ordinary swings are more likely to reach it. Because of fees, your real break-even sits slightly above the entry; see how fees move your break-even price. Decide these rules before you enter, not in the moment.
A stop that gets hit is a result, not a verdict. Over many trades, some stops will be triggered by noise just before the price turns, and that cost is part of the plan. The risk-reward ratio guide compares the stop distance with the target, and drawdown recovery math shows why keeping each loss small matters.
Common stop-loss mistakes
- Choosing the stop to fit a position size. The stop comes from the chart; the size comes from the stop.
- Stops inside normal daily noise. If the average day moves 3.8%, a 2% stop can be hit on an ordinary day.
- Ignoring fees and slippage. Both belong in the risk per unit.
- Widening the stop after entry. It raises the risk without anyone deciding to.
- No stop on a leveraged position. The liquidation price then becomes the stop, at a level you didn’t choose.
- Treating the stop as a guarantee. Gaps and flash crashes can fill it far below the stop price.
Our position size calculator takes your account size, risk percentage, entry, stop and fees, and returns the units, position value and maximum planned loss.
The bottom line
Fix the dollar risk first, place the stop where the trade idea is wrong and outside normal daily swings, and let the position size follow. Include fees and a slippage allowance, never widen a stop after entry, and remember that a stop limits a loss only when it fills near its price.
Frequently asked questions
How do traders decide where to place a stop-loss?
Most placement methods start from the price that would prove the trade idea wrong, such as just beyond a level the price was expected to hold. The next check is whether that stop sits outside the asset's normal daily range, so ordinary swings don't trigger it. The position size is then calculated from the stop distance. Choosing a distance only because it allows a bigger position reverses that logic.
Is there a standard stop-loss percentage for crypto?
No. A fixed percentage ignores how volatile the asset is. If a hypothetical coin's average daily range is 3.8% of its price, a 2% stop sits inside an ordinary day's movement, while a stop at twice the average range would be 7.6% away. What stays fixed is the dollar risk per trade; the position size adjusts to whatever stop distance the market requires.
Does a stop-loss guarantee my maximum loss?
No. A standard stop becomes an order to trade once the stop price is reached, and in a fast market it can fill significantly below the stop. In our example, a fill at $1,780 on a $1,900 stop turns a planned $100 loss into $217.65. A stop-limit order caps the fill price, but there is no guarantee it executes, which can leave the position open.
What happens if I move my stop-loss to break-even?
Moving the stop to your entry price cuts the planned loss to roughly the fees, about $1.96 in our example, but it also puts the stop closer to the current price, where ordinary swings are more likely to reach it. It is a trade-off, not a free improvement. Widening a stop is different: it always increases the amount you can lose.
Sources
- Stop Orders: Factors to Consider During Volatile Markets — FINRA
- Stop Order (glossary) — U.S. SEC — Investor.gov
- Customer Advisory: Understand the Risks of Virtual Currency Trading — U.S. Commodity Futures Trading Commission
- Day Trading: Your Dollars at Risk — U.S. Securities and Exchange Commission
This content is for education only and is not financial, investment, tax or legal advice. Crypto assets are volatile and you can lose money. Examples use hypothetical numbers. See our disclaimer and editorial policy.