Your risk budget
Use your entered equity or balance and chosen risk percentage.
Capital × Risk % ÷ 100
For an amount-based risk, use that amount directly. A $10,000 account with 1% entered risk has a $100 risk budget.
Position Size Calculator
Use this forex position size calculator to estimate your trade in lots and units from your account size, chosen risk and stop loss. Include commissions and adjust contract settings to see the estimated loss at your stop.
CCO at Quadcode · 8+ years in dealing
How to use this calculator
Set your risk
Choose your pair and account currency. Enter your capital and the amount or percentage you choose to risk.
Define the trade
Set a direction, planned entry and stop. Prices should reflect execution; the difference already includes any spread reflected in those prices.
Read your volume
See the rounded-down lots and base-currency units. Review costs, conversion and the estimated loss before using the result.
Calculated position size
— lots
Complete your trade to see the result.
Lots and units are calculated from your inputs.
Estimated loss at stop—
—- Risk budget
- —
- Stop distance
- —
- Unused budget
- —
Drag the marker or tap the chart to change your stop. Arrow keys move one price step. Your entered risk budget stays fixed.
No permitted position at this stop. Choose a closer stop or review your risk and costs.
How your risk budget is allocated
- Price loss at scenario exit
- —
- Round-trip commission
- —
- Fixed position fees
- —
- Unused risk budget
- —
Same risk budget, different stop distances
| Stop, pips | Lots | Loss at stop |
|---|
Each row includes your costs and slippage reserve. These are scenarios, not stop recommendations.
Estimated loss assumes execution at the entered stop plus your slippage reserve. Actual losses may be higher due to gaps, execution prices, exchange rates or additional costs.
Model assumptions ↗How to calculate position size
Start with the amount you choose to risk. Work out the loss on one lot at your stop, including your costs, then round the position down to an allowed volume.
Your position in lots
Allow for fixed fees before dividing by the loss and commission per lot.
(Risk − Fixed fees)
÷ (Loss + Commission per lot)
Loss per lot = absolute entry-to-exit price change × units per lot × the conversion rate into your account currency. Round lots down to the allowed step.
Forex lot size calculator example
A $10,000 account, a chosen 1% risk and a EUR/USD long entry at 1.10000 with a stop at 1.09500 give a 50-pip stop. With 100,000 units per lot, each lot risks $500 before fees.
Without fees, $100 ÷ $500 gives 0.20 lots. Add $7 round-trip commission per lot and the raw volume becomes 0.19724 lots. With a 0.01 lot step, that rounds down to 0.19 lots.
Example, not live market prices. Risk percentage is illustrative.
With $7 round-trip commission / lot0.19 lots
19,000 EUR base-currency units
- Price loss at stop
- $95.00
- Round-trip commission
- $1.33
- Estimated loss
- $96.33
- Share of account
- 0.9633%
Lot size, units and pip value
Lots measure trade volume. Pips measure price distance. Their monetary value depends on the contract and the currency in which you measure the result.
Lots become units
| Lots | Units |
|---|---|
| 1.00 | 100,000 |
| 0.10 | 10,000 |
| 0.01 | 1,000 |
Your broker may use different settings. A custom contract size changes the units represented by every displayed lot.
Pip size is not pip value
For the supported pairs, one pip is 0.0001 when the quote currency is not JPY, and 0.01 when it is JPY. The smaller displayed price step can be one tenth of a pip.
For EUR/USD in a USD account, 100,000 units × 0.0001 gives $10 per pip. Other pairs or account currencies require conversion. For a USD/JPY position measured in USD, this tool converts the JPY loss using the scenario exit price.
How stop loss and trading costs affect position size
The same risk budget can support different volumes. The stop distance and the costs on that volume determine the difference.
A wider stop changes the loss per lot
With the other assumptions held fixed, increasing the adverse distance raises the loss on each unit. The calculator reduces the volume so that the estimated loss remains inside the entered risk budget.
Include the full round trip
Per-lot commission includes opening and closing together. Fixed fees apply once to the entire position. Both reduce the volume available for price risk; they are not added after sizing the trade.
Keep execution assumptions consistent
Enter planned fill prices: Ask entry and Bid exit for a long, Bid entry and Ask exit for a short. Do not add spread again when it is already reflected in those prices. A slippage reserve models an additional adverse exit move.
Assumptions and limitations
One forex trade
The model supports 28 currency pairs and linear forex profit and loss. It does not measure existing positions, correlated exposure, margin availability or liquidation risk.
Entered rates and contract terms
Prices are user inputs, not live quotes. Contract settings are generic and editable. For a third account currency, the entered conversion rate is assumed unchanged at the modeled exit.
Specified costs only
The calculation includes entered round-trip commission, fixed fees and a slippage reserve. It does not calculate swap, tiered commissions, minimum commission tariffs or additional currency conversion fees.
Execution can differ
An ordinary stop does not guarantee the exit price. Market gaps, actual slippage and exchange-rate changes can produce a larger loss than the scenario shown.
About the author
Demetris Makrides
Chief Commercial Officer at Quadcode
Methodology & calculation checks
The calculator estimates forex position size from entered capital, chosen risk, entry and stop prices, currency conversion and trading costs. Calculation checks cover fees, contract sizes, volume steps and risk after rounding.
Last updated
See formulas and worked exampleEducational calculations, not investment advice. This tool estimates a single forex trade using the inputs and assumptions shown. It does not check available margin or your total portfolio exposure.
Frequently asked questions
What is a position size calculator?
A position size calculator estimates how many lots or units fit a risk budget at a chosen stop. This tool uses your forex pair, account capital, planned execution prices and entered costs.
What is the difference between lot size and position size?
They describe trade volume in different units. For a standard forex contract, 0.20 lots equals 20,000 base-currency units. Change units per lot in contract settings if your broker uses a different size.
How do I calculate forex lot size?
Divide the money available to risk, after fixed fees, by the estimated loss and round-trip commission for one lot. This lot size calculator then rounds down to the allowed volume step and checks the resulting risk.
Should I use account balance or equity?
Balance generally excludes unrealized profit or loss; equity includes it. Select the basis you intend to use and enter that value. The calculator uses your input and does not retrieve or assess your trading account.
Why does a wider stop loss reduce position size?
With the other assumptions held fixed, a wider adverse move increases the loss on each unit. Fewer units can then fit the same monetary risk budget. The stop scenarios table recalculates this relationship.
How do account currency and pip value affect the result?
The price change produces profit or loss in the pair’s quote currency. That amount must be converted into your account currency. A fixed dollar value per pip cannot be applied to every pair and account.
Are commissions and slippage included?
Only the costs you enter are included. Round-trip commission scales with lots; fixed fees apply once to the whole position. An optional slippage reserve moves the scenario exit beyond the stop. Swap, tiered tariffs and additional conversion charges are not modeled.
Does leverage change position size?
For the same position volume, entry and exit, leverage does not change the price loss. It affects the funds needed to open the trade. This tool does not check margin availability, leverage limits or liquidation levels.
Why is the result rounded down or below the minimum lot?
Rounding up can exceed the chosen risk. The calculator uses the largest permitted volume step within the budget and any maximum you enter. If even the minimum volume is too large, it reports that rather than suggesting a larger trade.
Can my actual loss exceed the calculated risk?
Yes. Gaps, changing exchange rates, execution prices and unmodeled costs can increase the loss. An ordinary stop does not guarantee its execution price. The slippage reserve is only a scenario assumption.
Does this calculator support gold, indices or crypto?
This version supports 28 forex pairs. Metals, indices and other products have different contract and calculation rules. Their specifications need a separate supported model.
Are my inputs stored or shared?
Calculations run in your browser without sending your account or trade inputs to a server. Copy and Share are optional. A calculation link contains your account size and trade inputs, which anyone receiving the link can read.
Explore Quadcode brokerage solutions
Explore our trading platform, back office and brokerage infrastructure.
Explore brokerage solutionsCalculation inputs are processed in your browser. Shared calculation links include the entered values. Read the model assumptions. For profit/loss, pip value and margin at a chosen volume, use the Forex Calculator.