Educational content. This article explains the position size formula and shows how it behaves across instruments. It does not constitute investment advice or a recommendation. CFD trading carries significant risk of loss and may not be suitable for all investors.
Position sizing is the calculation that turns a chosen risk amount into a number of lots. The formula is: lots = money risked / (stop-loss distance x contract size). Risking USD 100 with a 25-pip stop on EURUSD, where one pip is USD 10 per lot, gives 0.40 lots. The stop distance and the instrument, not the account balance alone, decide the answer.
This article gives the formula in its general form, applies it to five asset classes with figures from the Vanto feed, and covers the three places where the textbook answer needs adjusting: rounding, the minimum lot and the stop distance itself.
What Is Position Sizing?
Position sizing is the step that fixes how large a trade is before it is opened, so that a stop-loss hit costs a planned amount of money. It answers one question: given where the stop-loss will sit, how many lots make the loss at that price equal to the amount the trader decided to risk?
The decision comes in a fixed order:
- Choose the risk amount, usually a fixed percentage of account equity.
- Place the stop-loss by market logic, not by what the account can afford.
- Calculate the lots that make the distance between entry and stop equal to the risk amount.
Direction and entry are separate questions. A position size says nothing about whether the trade wins; it only caps what one loss costs. How the stop relates to the target is covered in what is the risk-reward ratio.
The Position Size Formula
The general formula works for every instrument because it uses money per price unit, not pips:
Lots = Risk amount / (Stop distance x Contract size)
The stop distance is in price units (for example 0.0025 on EURUSD, or USD 20 on gold). The contract size is the number of units one lot controls, taken from the symbol specification. Their product is the loss of one lot per stop, in the profit currency of the symbol. What is contract size in trading explains where the figure comes from.
For forex the same formula is often written with pips: lots = risk / (stop in pips x pip value per lot). What is a lot shows that version for EURUSD, and what is a pip covers pip value. The two forms give identical answers; the price-distance form is the one that also works for gold, indices and crypto, where "pip" is not a standard unit.
If the profit currency differs from the account currency, convert the result. On USDJPY the loss is in yen, so the yen amount is divided by the USDJPY rate to reach USD.
Worked Example: EURUSD
On EURUSD one lot is 100,000 EUR, and the profit currency is USD.
- Account equity: USD 10,000
- Risk per trade: 1%, which is USD 100
- Stop distance: 25 pips, which is 0.0025
- Loss of one lot at the stop: 0.0025 x 100,000 = USD 250
- Lots: 100 / 250 = 0.40
The 0.40 lot trade loses USD 100 if the stop is hit, and the position is worth about USD 44,806 at the snapshot bid of 1.12014 (0.40 x 100,000 x 1.12014). That is about 4.5 times the account balance in notional terms, which is why leverage matters for the margin deposit and why it plays no part in the sizing formula. The risk is set by the stop distance and the lots; leverage only decides how much of the account is held as margin.
The Same Risk Across Five Asset Classes
One risk amount gives very different lot sizes because the contract sizes differ. The table sizes a USD 100 risk (1% of a USD 10,000 account) with an illustrative stop for each instrument. The stops are example distances for the arithmetic, not suggestions.
| Instrument | Class | Contract size | Example stop | Loss of 1 lot at stop | Lots (raw) | Lots (rounded down) | Real risk |
|---|---|---|---|---|---|---|---|
| EURUSD | Forex | 100,000 | 25 pips | USD 250 | 0.400 | 0.40 | USD 100.00 |
| USDJPY | Forex | 100,000 | 25 pips | USD 157.95 | 0.633 | 0.63 | USD 99.51 |
| XAUUSD | Metals | 100 | USD 20 | USD 2,000 | 0.050 | 0.05 | USD 100.00 |
| XAGUSD | Metals | 5,000 | USD 0.80 | USD 4,000 | 0.025 | 0.02 | USD 80.00 |
| UKOIL | Energies | 100 | USD 1.50 | USD 150 | 0.667 | 0.6 | USD 90.00 |
| US500 | Indices | 1 | 40 points | USD 40 | 2.500 | 2.50 | USD 100.00 |
| JP225 | Indices | 1 | 300 points | USD 1.90 | 52.76 | 52 | USD 98.56 |
| BTCUSD | Crypto | 1 | USD 1,500 | USD 1,500 | 0.067 | 0.06 | USD 90.00 |
Source: Vanto feed snapshot, 10 October 2026. Contract sizes, volume steps and the USDJPY rate (158.282) are from the feed. The JP225 loss is in yen and converted to USD at the USDJPY rate.
Three things show up in the table:
- Lot counts are not comparable across instruments. 0.05 lots of gold, 2.5 lots of US500 and 0.40 lots of EURUSD carry the same planned risk. Comparing lot counts says nothing about exposure.
- The volume step changes the answer. UKOIL trades in steps of 0.1 lot and JP225 in whole lots, so the raw result is cut to the next step down.
- Wider stops mean smaller positions. Doubling the stop on EURUSD from 25 to 50 pips halves the lots from 0.40 to 0.20 for the same USD 100.
The margin side is separate. At the leverage caps of the asset classes (forex 1:500, metals 1:500, indices 1:100, energies 1:100, crypto 1:10), the 0.05 lot gold position needs about USD 42 of margin, and the 0.06 lot BTCUSD position needs about USD 497, because the crypto cap is 1:10. What is margin in trading explains the calculation, and what is leverage in trading explains why leverage amplifies losses as well as gains.
Why Real Risk Is Below the Budget: Rounding
The platform accepts volumes only in multiples of the volume step, so a calculated size is rounded. Rounding down keeps the real risk at or under the budget; rounding up would exceed it.
The cost of rounding depends on the step relative to the position:
- On EURUSD at 0.40 lots, the step of 0.01 is 2.5% of the position, so rounding is negligible.
- On XAGUSD, 0.025 lots becomes 0.02, a 20% cut, so the trade risks USD 80 instead of USD 100.
- On UKOIL, 0.667 lots becomes 0.6 because the step is 0.1 lot, so the trade risks USD 90.
Small budgets on large-contract instruments feel the step most. If the rounded risk is too far under the plan, the options are to widen the risk amount slightly or accept the smaller position. Rounding up to "get closer" is a decision to risk more than planned and should be made as such.
When the Minimum Lot Exceeds the Risk Budget
Every symbol has a minimum volume, and that floor can make the formula's answer impossible to place. If the result is below the minimum lot, the smallest allowed trade already risks more than the budget.
The table shows the widest stop that fits a USD 5 risk budget (1% of a USD 500 account) at the minimum lot of each instrument.
| Instrument | Minimum lot | Units at minimum | Widest stop within USD 5 |
|---|---|---|---|
| EURUSD | 0.01 | 1,000 EUR | 50 pips |
| XAUUSD | 0.01 | 1 troy ounce | USD 5 |
| XAGUSD | 0.01 | 50 troy ounces | USD 0.10 |
| UKOIL | 0.1 | 10 barrels | USD 0.50 |
| US500 | 0.01 | 0.01 index units | 500 points |
| JP225 | 1 | 1 index unit | 791 points |
| BTCUSD | 0.01 | 0.01 bitcoin | USD 500 |
Source: Vanto feed snapshot, 10 October 2026. The calculation is USD 5 / (minimum lot x contract size); the JP225 loss is in yen and converted at the USDJPY rate of 158.282.
On silver, a USD 5 budget fits only a USD 0.10 stop at the minimum lot, which is a very tight distance for that instrument. The mismatch is a property of the contract, not an error. The practical meaning is that on some instruments a small account cannot take a position with a market-logic stop at 1% risk. What is minimum lot size in trading lists the minimums, steps and maximums across the catalogue.
Moving the stop closer to make the trade "fit" is the wrong fix, because it ties the stop to the account rather than to the market. The honest choices are a larger risk amount for that trade, a different instrument, or no trade.
Why a Fixed Percentage Is Used
Fixed-fraction sizing risks the same percentage of current equity on each trade. The reason is arithmetic: losses compound, and recovering from them is not symmetric.
| Account drawdown | Gain needed to recover |
|---|---|
| 5% | 5.3% |
| 10% | 11.1% |
| 20% | 25.0% |
| 30% | 42.9% |
| 50% | 100.0% |
The recovery gain is drawdown / (100% - drawdown). A loss of 50% needs a gain of 100%, so every loss that is avoided is worth more than the same gain.
The risk percentage controls how quickly a losing streak reaches those levels. A streak of ten consecutive losses leaves the following balance:
| Risk per trade | After 5 losses | After 10 losses |
|---|---|---|
| 1% | 95.1% | 90.4% |
| 2% | 90.4% | 81.7% |
| 5% | 77.4% | 59.9% |
| 10% | 59.0% | 34.9% |
Arithmetic: balance after n losses = (1 - risk%)^n. These are illustrations of compounding, not predictions of any streak.
Small fixed percentages such as 1% or 2% per trade are common examples, and the table shows why a small figure matters: at 1% a streak of ten leaves a recoverable account, while at 10% it does not. The percentage is a choice with a trade-off, not a rule. Because the amount is a percentage of current equity, the lots shrink after losses and grow after gains.
Common Mistakes in Position Sizing
The formula is simple, and the errors come from the inputs and from skipping it.
Sizing by lots instead of by risk. Trading "0.10 lots on everything" gives USD 100 of risk on one instrument and USD 200 or more on another with the same stop in different units. The table above shows how much the contract size matters.
Ignoring slippage and gaps. A stop-loss is an order, not a guaranteed price. If the fill is 5 pips beyond a 25-pip stop on a 0.40 lot EURUSD position, the loss is 0.40 x 30 x USD 10 = USD 120, not USD 100. Gaps over weekends and news releases can be larger. What is slippage in trading explains when the fill differs from the stop price. Some traders size with a margin for this; that is a decision about the risk amount, not a change to the formula.
Setting the stop after choosing the lots. If the lots come first and the stop is moved to make the loss "acceptable", the formula has been run backwards. The stop should reflect the market structure, such as recent volatility described in what is volatility in trading, and the lots should follow from it.
Using the wrong contract size. Contract sizes differ by symbol and broker. The figures in this article are from the Vanto feed; another broker's gold or index contract may differ, so check the symbol specification before applying any formula.
Forgetting costs and holding time. Spread, commission and swap are not part of the sizing formula, but they change the real result of a trade. Why trading costs are more than the spread covers them.
Counting open positions separately. The risk percentage applies to each trade, but several open trades add up. Three positions each risking 1% put 3% of the account at risk at once if the stops are hit together, particularly when the instruments are correlated.
Position Sizing Does Not Prevent a Stop-Out
Position size limits the loss at the stop-loss, but only while the stop works as planned. Vanto accounts have a margin call level of 100% and a stop-out level of 50%. If equity falls far enough against the used margin, positions close automatically whether or not the stop-loss has been reached. What is the stop-out level in trading shows the distance for a worked case.
A position sized at 1% risk uses a small share of equity per trade, so the stop is normally hit long before the stop-out level. Sizing by risk and not by available margin is what keeps that order of events.
Frequently Asked Questions
How do you calculate position size in forex?
Divide the money you are willing to lose by the stop distance in price multiplied by the contract size. On EURUSD, USD 100 of risk with a 25-pip stop and USD 10 per pip per lot gives 100 / (25 x 10) = 0.40 lots. Convert the result to the account currency if the pair's profit currency differs.
What percentage of the account should one position risk?
There is no universal figure. Small percentages such as 1% or 2% are common examples, because at 1% ten consecutive losses leave 90.4% of the balance, while at 10% they leave 34.9%. The right level depends on the trader's tolerance for drawdown and on the strategy.
Is position size the same as lot size?
No. Lot size is the volume of the order, and position size in the risk sense is the lot size that results from the formula. The same lot size carries different risk on different instruments, as the table shows: 0.05 lots of XAUUSD and 0.40 lots of EURUSD can carry the same USD 100 risk.
Does leverage change the position size?
No. Leverage changes the margin required to hold the position, not the loss at the stop-loss. A 0.40 lot EURUSD trade with a 25-pip stop risks USD 100 whether the leverage is 1:100 or 1:500. Leverage only decides how much equity is locked as margin.
What if the minimum lot risks more than my budget?
Then the trade does not fit the budget at that stop distance. On a USD 5 budget, the 0.01 lot minimum on XAGUSD fits only a USD 0.10 stop. The options are a bigger risk amount, a different instrument or skipping the trade; narrowing the stop to fit changes the trade.
Should position size change when volatility changes?
The formula already adjusts when the stop distance does. If a wider stop is needed because volatility is higher, the same risk amount produces fewer lots: 50 pips instead of 25 halves 0.40 lots to 0.20. The risk amount stays fixed while the lots move.
Calculate the Numbers for Your Own Account
The trading calculator shows contract size, pip value and margin for each Vanto symbol, which are the inputs for the formula above. A demo account lets a trader place sized positions and see the real loss at the stop without risking capital.
Risk warning. Trading securities, futures, options, and contracts for differences are complex financial instruments that require knowledge and understanding. Prices can fluctuate significantly and securities may become valueless. Investors may incur losses exceeding the potential for profits. Trading on margin can result in losses greater than the amount initially deposited. Past performance is not necessarily a guide to future performance. The information in this article is for educational purposes only and does not constitute investment advice, a recommendation, or an offer to buy or sell any financial instrument. Consider whether CFD trading is appropriate for your circumstances and seek independent advice if necessary.