Crypto Position Sizing: Same Dollar Risk, Coins That Swing Differently

Crypto has no lots or pips. Your position size is a number of coins, and the right question isn’t “how much should I buy” but “how much do I lose if price reaches my Stop loss”. This article sizes BTC and ETH positions step by step, shows why a coin that swings harder needs a smaller position, and then adds three things people often forget: fees on both sides, price jumping past the Stop loss, and holding several coins that really move as one.

The one formula you need

Number of coins = amount you accept to lose ÷ (entry price − Stop loss price)

The divisor is the Stop loss distance in dollars per coin, so the result comes out directly as a number of coins. The amount you accept to lose is your balance times the percentage you risk per trade. For where 1% comes from, read Risk 1% per trade, and for the same idea in Forex, Lot size from your Stop loss.

Every example here uses a 5,000-dollar balance with 1% risk = 50 dollars per trade. All coin prices are made-up prices, not real market prices and not a price forecast.

BTC example

Made-up prices: buy BTC at 60,000 dollars, with the Stop loss below support at 58,200.

1. Stop loss distance = 60,000 − 58,200 = 1,800 dollars per coin (= 3% of the entry price)
2. Number of coins = 50 ÷ 1,800 = 0.02778 BTC
3. Position value = 0.02778 × 60,000 ≈ 1,667 dollars

Check: if price falls to 58,200 you lose 0.02778 × 1,800 ≈ 50 dollars, as planned (before fees, see further down).

ETH example

Made-up prices: buy ETH at 2,500 dollars, with the Stop loss at 2,375.

1. Stop loss distance = 2,500 − 2,375 = 125 dollars per coin (= 5% of the entry price)
2. Number of coins = 50 ÷ 125 = 0.4 ETH
3. Position value = 0.4 × 2,500 = 1,000 dollars

Both trades risk the same 50 dollars, but the BTC position is worth 1,667 dollars while the ETH position is worth only 1,000, because the ETH Stop loss is further away in percentage terms.

Why the Stop loss percentage differs by coin

Divide both sides of the formula by the entry price and you get another form that doesn’t depend on the coin’s price at all.

Position value = dollar risk ÷ Stop loss distance in %

For example 50 ÷ 3% = 1,667 and 50 ÷ 5% = 1,000, matching the two examples above. Whether a coin is expensive or cheap doesn’t matter. What sets the size is how many percent away the Stop loss is.

So why should the distance differ? Because each coin swings by a different amount. In general BTC moves less in percentage terms than ETH, and smaller coins with thinner liquidity often swing harder still. Put a 3% Stop loss on a coin that normally moves 7% a day, and ordinary noise will hit it almost every day. A sensible Stop loss has to widen with volatility, and the position has to shrink with it.

Using ATR% to compare coins

ATR (Average True Range) is the average distance price covers per bar. The default is 14 bars with Wilder’s smoothing, explained in full in ATR and volatility. ATR is in price units: BTC’s ATR is in the thousands of dollars, a 10-dollar coin’s is in cents, so you can’t compare them directly. Convert it to a percentage of price first.

ATR% = ATR ÷ price × 100

An example with made-up daily ATR(14) values, a Stop loss of 2 times ATR on every coin, and the same 50-dollar risk:

Coin (made-up)	Price	ATR(14)	ATR%	SL 2×ATR	Position value	Coins
BTC	60,000	1,800	3%	6%	833 USD	0.0139
ETH	2,500	100	4%	8%	625 USD	0.25
Small coin A	10.00	0.70	7%	14%	357 USD	35.71

Working the ETH row: Stop loss = 2 × 100 = 200 dollars per coin, coins = 50 ÷ 200 = 0.25 ETH, value = 0.25 × 2,500 = 625 dollars, which is also 50 ÷ 8%.

The rule of thumb from the table: if a coin’s ATR% is twice as high, its position value should be about half, as long as you use the same ATR multiple for the stop. ATR% also compares the same coin across time. In a quiet month ATR% is low and the size can grow by itself. In a wild month the size shrinks by itself while the risk stays the same.

ATR only tells you how wide price has swung in the past. It doesn’t tell you which way price will go, and it doesn’t promise tomorrow will swing the same.

Count fees on both sides in the risk

Every time a trade hits the Stop loss you pay fees twice: once to buy and once to sell. Most exchanges charge a percentage of the traded value, and orders that fill immediately (taker), such as Market or Stop market orders, usually pay more than orders that rest in the book (maker). Real rates differ by venue, so check your exchange’s fee page.

This example assumes a taker fee of 0.1% per side, using the same BTC trade (entry 60,000, Stop loss 58,200).

If you buy 0.02778 BTC with the plain formula:

1. Entry fee = 0.02778 × 60,000 × 0.1% ≈ 1.67 dollars
2. Exit fee at the Stop loss = 0.02778 × 58,200 × 0.1% ≈ 1.62 dollars
3. Total loss = 50.00 + 1.67 + 1.62 ≈ 53.28 dollars, about 6.6% more than planned

The fix is to add the per-coin fees to the Stop loss distance.

Coins = dollar risk ÷ [Stop loss distance + fee% × (entry price + Stop loss price)]

1. Fees per coin = 0.1% × (60,000 + 58,200) = 118.2 dollars
2. Risk per coin = 1,800 + 118.2 = 1,918.2 dollars
3. Coins = 50 ÷ 1,918.2 ≈ 0.02607 BTC (worth about 1,564 dollars)

Check: the price loss is 0.02607 × 1,800 ≈ 46.92, plus fees ≈ 3.08, = 50.00 dollars exactly. The same method on the earlier ETH trade gives 50 ÷ (125 + 4.875) ≈ 0.3850 ETH instead of 0.4.

Fees take roughly 2 × fee% ÷ Stop loss% of your risk. At a 3% stop that’s about 0.2 ÷ 3 ≈ 7% (6.6% exactly). But with a 0.5% stop (entry 60,000, Stop loss 59,700) the fees are 119.7 dollars per coin against a 300-dollar distance, about 40% of the stop distance. That’s why very short-term crypto trading with tight stops costs more than it looks. It’s the same idea as spread in Spread cost per trade.

The site’s crypto position calculator works from the price distance only and doesn’t include fees yet. To use it, first lower the risk you enter by the share above.

A 24/7 market, and price jumping past your stop

Crypto trades 24 hours a day, every day, so there is no Monday gap like Forex after the weekend close. That doesn’t mean price fills smoothly at every level. Liquidity is often thinner at night and at weekends, big news that lands while you sleep can push price through several levels in moments, and exchanges sometimes pause for maintenance.

So a Stop loss doesn’t guarantee a price. A Stop market order sells at the next price someone will take, which can be worse than your stop. A Stop limit sets a worst price, but if price runs past it fast the order may not fill at all and the trade stays open. See how each order type behaves in Order types explained.

Size comes from the Stop loss, but on a day the market jumps the real loss can be bigger. The thinner the coin’s liquidity, the more room to leave.

A simple allowance: risk less per trade on small coins than on BTC or ETH, and don’t hold a large position overnight if you can’t absorb a jump.

BTC + ETH + other coins is mostly one bet

Most coins tend to move in the same direction as BTC, especially on days the market drops hard, which are exactly the days several stops fire together. Open BTC, ETH and small coin A at 50 dollars risk each, all in the same direction, and on such a day you could lose the full 150 dollars, 3% of the balance, in one go, even though each trade “only risks 1%”.

A safer way to think: set a cap on the combined risk of crypto trades in the same direction first, then split it. For example, with a 2% cap = 100 dollars, three trades get about 33.33 dollars each. The 2% is an example, not a standard. This cap works well alongside a daily loss limit.

Stop orders on spot vs futures

Spot means buying the actual coin. The most you can lose is what you paid, and there’s no liquidation. Available stop orders vary by exchange: some offer only Stop limit or OCO, others also have Stop market. Check what yours offers and confirm the stop actually sits on the exchange.

Futures (including perpetuals) use leverage and let you go short. The sizing formula is exactly the same. Leverage only changes the margin you post. For example, a 0.02607 BTC position worth about 1,564 dollars needs about 312.79 dollars of margin at 5 times leverage, but if price reaches the Stop loss you still lose about 50 dollars.

Extra checks on futures:

• Liquidation price must be well beyond your Stop loss. If it’s closer, the system closes you out before your stop fires. See how it works in Leverage, margin and stop out
• Trigger price: some exchanges let you choose whether a stop uses the last traded price or the mark price, which can behave differently in a fast market
• Funding fees on perpetuals are paid or received at intervals for as long as you hold. On longer holds, count them as a cost. Read more in Perpetual futures and funding

Funding intervals, fee rates and how liquidation is calculated vary by exchange and contract. Check the contract specification of the one you actually use.

Common mistakes

• Sizing from the money you have, not the money you accept to lose. Buying 1,000 dollars every time makes a wide-stop trade riskier than a tight-stop trade many times over
• Using the same Stop loss percentage on every coin. A coin that swings hard gets stopped out by ordinary noise. Check ATR% first
• Squeezing the stop to buy more. The dollar risk is the same, but the stop gets hit more often and fees take a bigger share
• Forgetting the exit fee. A trade meant to lose 50 loses more than 50 every time
• Treating leverage as lower risk. Leverage lowers margin, not the loss at the Stop loss
• Holding several coins and calling it diversified. Most still follow BTC, so count the combined risk
• Not recording real results against the plan. Log actual slippage and fees in a trading journal to learn how much room your coins need