Position Sizing: Turning a Risk Percentage into a Lot Size
A lot size calculator converts the money you are willing to risk into a number of lots the position can carry.
- Money at risk you set
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- Actual loss at stop
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- Pip value at this size
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Ignores spread, commission and slippage. A stop can fill worse than its price in fast markets.
Worked example
USD/AED 3.67 · pulled 2026-09-28| Step | What | Calculation | Amount |
|---|---|---|---|
| 1 | Money at risk | 7 300.00 × 1% | AED 73.00 |
| 2 | Pip value, 1 standard lot | USD 10.00 × 3.67 | AED 36.70 |
| 3 | Risk per pip | 73.00 ÷ 25 pips | AED 2.92 |
| 4 | Exact position size | 2.92 ÷ 36.70 | 0.0796 lots |
| 5 | Rounded down to 0.01 lot | floor(0.0796, 0.01) | 0.07 lots |
| 6 | Actual loss if the stop is hit | 0.07 × 36.70 × 25 | AED 64.23 |
The risk percentage is the input, the lot size is the output
Decide first what share of the account you will lose if the trade fails. That is the risk percentage, and it is the only figure you choose freely. The calculator then works backwards from the stop loss to a lot size that makes that loss real.
The order matters. Traders who pick a lot size first and a stop second are letting the market decide their risk. Set the stop where the idea is wrong, then let the calculator tell you how large the position may be.
The live calculator on this page does that arithmetic for you. Type the balance, the risk percentage and the stop distance, and read the lot size it returns.
Stop distance and pip value decide how much room one lot needs
A stop placed far from entry allows fewer lots for the same risk. A tight stop allows more. This is why two trades with identical risk percentages can carry very different position sizes.
Pip value is the second half of the equation, and it is not constant. It changes with the pair, the quote currency and the size of the contract. A position in a pair quoted in US dollars and one quoted in another currency do not lose the same amount per pip.
Index products such as the NAS100 work on the same principle but not the same unit. There is no pip in the currency sense, so the calculator needs the value of one index point per contract. Use the contract specification on your broker's platform, not a remembered figure.
Leverage changes the margin, not the risk
Leverage lets you open a larger position with less capital set aside. It does not change what a losing trade costs. A position that loses more than your risk percentage loses that amount whether leverage was five times or fifty.
The practical effect is that high leverage removes a natural brake. Without it, a small account could not open a position large enough to matter. With it, the same account can open a position whose stop loss represents most of the balance.
Treat the leverage figure as a constraint on margin, and the risk percentage as the constraint on loss. They are separate decisions, and only the second one protects the account.
Where to check the numbers the calculator cannot know
The calculator cannot see your broker's contract sizes, financing charges or execution rules. Those live on the broker's own pages, and they differ between account types. Check the contract specification before you rely on any position size.
Funding and withdrawal mechanics matter too. Bank transfer is the main rail used by UAE residents, with local bank transfer, card and international wire also available. Confirm the settlement time on the broker's funding page and in your banking app before you size a trade around money that has not arrived.
If a dispute arises, the route depends on the licence. Three regimes coexist: the Capital Market Authority onshore, the DFSA in the DIFC and the FSRA in the ADGM. A broker's licence says which one, and that changes who handles a complaint. You can check the CMA register of licensed companies at uaecma.gov.ae.
Session timing is the last input worth knowing. Sydney runs 02:00 to 11:00 GST, Tokyo 04:00 to 13:00, London 12:00 to 21:00 and New York 17:00 to 02:00. The London and New York overlap, 17:00 to 21:00 GST, is when spreads on major pairs are typically tightest, which affects the cost of the stop you have already chosen.
Questions
A lot size calculator works forwards from risk to position size, telling you how much you may open. A forex profit calculator works the other way, taking an entry, an exit and a size and reporting the result. The two are often shown together because a trader checks the risk before the trade and the outcome after it. Neither replaces the broker's own contract specification.
No. The calculator sizes the position from the risk percentage and the stop distance. Leverage only determines how much margin is set aside to hold that position. A higher leverage setting lets you open larger positions, but it does not make a given position safer or more dangerous. Your risk percentage is what caps the loss.
Currency pairs are sized in lots with a pip value, while index products such as the NAS100 are sized in contracts with a value per index point. The calculator needs that point value, which comes from the broker's contract specification. Using a pip value for an index will give a position size that has nothing to do with your intended risk.