Position Sizing Explained: How to Calculate How Much to Risk on Every Trade
In short: Position sizing is the decision of how large a trade to open, and it is made by working backwards from one number: the amount of money you are willing to lose if the trade fails. Decide that figure first, measure the distance from your entry to your stop loss, find out what one pip is worth on that instrument, and divide. Most traders risk 1% to 2% of account equity per trade. The reason is arithmetic, not superstition: losses compound against you faster than gains compound for you, and a size that feels reasonable on a winning run is the same size that ends an account on a losing one.
Why this decision outranks your entry
Traders spend most of their time on entries. Entries decide whether a trade wins. Position size decides whether you are still trading in six months.
The reason is the asymmetry of recovery. A loss of a given percentage always requires a larger percentage gain to get back to where you started, and the gap widens fast:
| If you lose | You need this gain to break even |
|---|---|
| 5% | 5.3% |
| 10% | 11.1% |
| 20% | 25.0% |
| 30% | 42.9% |
| 50% | 100.0% |
| 70% | 233.3% |
| 90% | 900.0% |
A 10% drawdown is an ordinary bad month. A 50% drawdown requires you to double what is left just to return to the starting line. Below about 30%, the maths stops being an inconvenience and starts being the whole problem.
Position sizing is what keeps you in the top rows of that table.
What 1% actually buys you
Every strategy has losing streaks. Ten losses in a row is not evidence that something is broken; it is a normal outcome for a system that wins 45% of the time. What matters is what ten losses do to the account.
This is a run of ten consecutive losing trades, risking a fixed percentage of current equity each time:
| Risk per trade | Equity left after 10 losses | Drawdown | Gain needed to recover |
|---|---|---|---|
| 1% | 90.4% | −9.6% | +10.6% |
| 2% | 81.7% | −18.3% | +22.4% |
| 3% | 73.7% | −26.3% | +35.6% |
| 5% | 59.9% | −40.1% | +67.0% |
| 10% | 34.9% | −65.1% | +186.8% |
| 20% | 10.7% | −89.3% | +831.3% |
At 1%, ten straight losses cost you under 10% and you need a 10.6% gain to recover. Unpleasant, survivable, and you can keep trading the same plan.
At 10%, the same ten trades take two-thirds of the account and you need to nearly triple what is left. At that point, most traders abandon the strategy, usually right before it would have worked.
Note what changes between those rows: not the strategy, not the entries, not the win rate. Only the size.
The formula
Four inputs. One division.
Position size = Risk amount ÷ (Stop distance × Value per pip)
1. Risk amount. A percentage of current account equity, converted to money. On a $5,000 account at 1%, that is $50. Use current equity, not your original deposit, so the size shrinks automatically during a drawdown and grows as the account does.
2. Stop distance. The gap between your entry and your stop loss. This should come from the chart — a structural level, or a volatility measure such as Average True Range never from how much you can afford to lose. Deciding the stop from your wallet rather than the market is the single most common cause of stopped-out-then-reversed trades.
3. Value per pip or point. What one unit of movement is worth per lot on that specific instrument. This is where most calculation errors happen.
4. Divide, then round down. Rounding up quietly pushes you over the risk limit you just set.
Know what a pip is worth before you trade the instrument
The same lot size means wildly different risk depending on what you are trading:
| Instrument type | Contract basis | Value per pip/point, 1 standard lot |
|---|---|---|
| EUR/USD, GBP/USD, AUD/USD | 100,000 units | $10 per pip (fixed) |
| USD/JPY and JPY crosses | 100,000 units | ~$6.35 per pip at 157.50 varies with the rate |
| Gold (XAU/USD) | 100 ounces | $100 per $1 move |
| Crude oil | 1,000 barrels | $1,000 per $1 move |
| Index CFDs | Varies by contract | Check the instrument specification |
Two things to take from this table.
JPY pairs are not fixed. The pip value is 1,000 JPY converted to your account currency, so it moves with the exchange rate. At 140 it is $7.14; at 160 it is $6.25. Small, but it compounds across many trades.
Never assume. In MT5, right-click the instrument in Market Watch and open Specification to see contract size and tick value. Guessing here produces errors of several hundred percent, not a few percent.
Three worked examples, one account, identical risk
Account: $5,000. Risk per trade: 1% = $50. Watch what happens to the lot size.
EUR/USD, 128-pip stop, $10 per pip
$50 ÷ (128 × $10) = 0.039 → 0.03 lots
Gold, $97.50 stop, $100 per $1 move
$50 ÷ (97.50 × $100) = 0.005 lots
An index CFD at $1 per point, 45-point stop
$50 ÷ (45 × $1) = 1.11 contracts
Three completely different numbers 0.03, 0.005, 1.11 and all three risk exactly $50. That is the entire point of the exercise.
A trader who uses a habitual "0.1 lots" across all three is risking $128 on the first, $975 on the second and $4.50 on the third. On a $5,000 account, the gold trade alone is a fifth of the account on a single idea, taken by accident.
The minimum lot catch. MT5 typically has a 0.01 minimum. The gold example calculates to 0.005, below that floor. At 0.01 the smallest trade available that position risks about $97.50, nearly 2% of the account. That is not a reason to ignore the maths. It is the maths telling you that this instrument, at this stop distance, is too large for this account. Choose a smaller stop with a different setup, trade something else, or take the trade knowing the real number.
Start thinking in R
Once sizing is consistent, something useful follows: every trade risks the same amount, so you can stop counting money and start counting R, where 1R is your risk per trade.
A trade that makes twice what you risked is +2R. A full stop-out is −1R. Half off the table early is −0.5R.
This matters because it makes results comparable. A $50 win on gold and a $50 win on EUR/USD are both +1R, even though the lot sizes differ by a factor of six. You can then ask the only question that counts: across 100 trades, is the sum of my R positive?
It also reframes the win rate. A strategy that wins 40% of the time at +2R average is strongly profitable. A strategy that wins 70% at +0.3R, with full −1R losses, is not. You cannot see that difference in a currency-denominated P&L where every trade was a different size.
The hidden sizing error: correlated positions
You size three trades at 1% each and believe you have 3% at risk spread across three ideas.
Long EUR/USD. Short USD/CHF. Long GBP/USD.
That is not three ideas. It is one idea short US dollar expressed three times. If the dollar rallies, all three stops are hit together. You have roughly 3% riding on a single outcome, and you did not decide to do that.
The same applies elsewhere. Long AUD and long copper is one bet on Chinese demand. Long gold and short the dollar overlap heavily. Two index CFDs on the same region are close to the same trade.
Two habits fix it:
- Cap total open risk, not just per-trade risk. A common limit is 5% across all open positions. Hit the cap and you stop opening new ones until something closes.
- Count correlated positions as one. Before adding a trade, ask what single event would stop out everything you hold. If the answer covers most of your open positions, you have one position, not several.
Leverage and margin are not risk
These get conflated constantly, and the distinction is simple:
- Position size determines how much money you lose if the stop is hit.
- Leverage determines how much margin that position ties up.
You can hold a 0.03-lot position at 1:30 or 1:500 leverage. The loss at your stop is identical. Only the margin requirement differs.
So higher leverage does not make a trade riskier by itself. What it does is remove the barrier that would otherwise stop you opening a position far too large for the account. The discipline has to come from the sizing calculation, because leverage will not supply it.
Related practical points: some instruments carry lower leverage caps — 1:400 on CHF pairs, 1:100 on USDTRY and EURTRY, 1:50 on USDCNH — which changes margin, not your risk per trade. And margin call sits at 80%, which is a consequence of oversizing, not a risk management tool.
What should change your position size, and what shouldn’t
Should:
- Account equity, as it rises and falls
- Stop distance, because a wider stop demands a smaller size at the same risk
- The instrument’s volatility and pip value
- A documented, tested change to your risk percentage
Should not:
- How confident you feel about this particular setup
- How the last three trades went
- A desire to make back a loss
- How good the chart looks
The second list is where accounts are lost. Increasing size after losses — doubling down to recover — converts a drawdown into a terminal one, because the larger size is deployed exactly when the strategy is already out of sync with the market.
Common mistakes
- Sizing first, stop second. Opening the position and then deciding where the stop goes means the stop lands wherever the fear becomes unbearable, which is rarely a sensible level.
- Using deposit instead of current equity. After a 20% drawdown, 1% of your original deposit is 1.25% of what you actually have.
- Rounding up. 0.039 becomes 0.04 "because it’s close". That is 2.5% more risk on every trade, forever.
- Ignoring the cost of holding. Swap charges apply to positions held overnight and are processed daily at 00:00 GMT+2. They do not change the risk at your stop, but they do change the result.
- Forgetting gaps. A stop is an instruction to exit at the next available price, not a guarantee of that price. Over weekends and around major events, the fill can be worse than the level. Size with the understanding that your worst case is occasionally larger than the calculation.
Frequently asked questions
What is position sizing in trading?
Position sizing is deciding how large a trade to open, based on how much money you are willing to lose if the trade hits its stop loss. It is calculated as risk amount divided by stop distance multiplied by the value per pip.
How much should I risk per trade?
Most traders use 1% to 2% of account equity. At 1%, ten consecutive losses cost under 10% of the account and need only a 10.6% gain to recover. At 10% risk, the same ten trades cost 65% and need a 187% gain.
What is the position sizing formula?
Position size = risk amount ÷ (stop distance × value per pip or point). On a $5,000 account risking 1% with a 128-pip stop on EUR/USD at $10 per pip: $50 ÷ (128 × $10) = 0.03 lots.
Does position size depend on leverage?
No. Position size determines your loss if the stop is hit; leverage determines the margin required to hold it. The same position risks the same money at any leverage. Leverage only changes how large a position you are able to open.
What is an R-multiple?
1R is the amount you risk on a trade. A trade making twice the risk is +2R; a stop-out is −1R. Measuring results in R makes trades comparable across instruments of very different sizes.
Should I increase my size after a losing streak?
No. Fixed-percentage sizing reduces position size automatically during a drawdown, which is the correct direction. Increasing size to recover losses deploys more capital precisely when the strategy is performing worst.
Run the numbers before you risk money. Open a free 30-day ABET demo account, work the formula on three different instruments, and see how far apart the lot sizes land for the same risk. Live prices on MetaTrader 5, nothing at stake. Open a demo account: /register?demo=1
Risk warning: CFDs and leveraged forex are complex instruments and carry a high risk of losing money rapidly due to leverage. This article is educational and is not investment advice or a recommendation to trade any instrument. Position sizing and stop losses manage risk; they do not eliminate it, and stop losses are not guaranteed to fill at the specified price.