Irish Calculators
Saving & investing

Position and Lot Size Risk Calculator

Find a lot size that fits the risk amount you enter under the stated stop-distance and cost assumptions. Supply the point value in your account currency; gaps and slippage can make losses larger.

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Your numbers

%
In the same currency as account equity.
Display currency only. Convert all inputs to this currency before calculation.
Your figures stay on this device.

How the calculation works

Position sizing starts with a permitted cash-risk budget rather than with leverage or an attractive trade value. The calculator uses the loss per lot at the entered stop distance, adds estimated trading costs and rounds the size down to an allowed lot increment.

Lots = floor[(equity × risk fraction) ÷ (stop distance × point value per lot + costs per lot) ÷ lot increment] × lot increment.

  1. Convert the risk percentage into cash

    Multiply account equity by the risk percentage. This creates the monetary allowance used for the position-size calculation.

  2. Estimate the loss per lot

    Multiply stop distance by cash value per point per lot and add round-trip cost per lot. Both quantities must be on the same account-currency basis.

  3. Apply the trading increment

    Divide the cash budget by loss per lot, then round down to the specified lot step. The resulting planned risk can be below the full budget because fractional increments are excluded.

Worked example: Check Position size (lots)

Sample inputs demonstrate the method. They are not a forecast or product offer.

The first example risks 1% of a 10,000 account, or 100. A 50-point stop at 10 per point costs 500 per lot, so 100/500 gives 0.20 lots, already matching the 0.01 increment.

Account equity
10000
Account risk budget (%)
1
Stop distance in points or pips
50
Cash value per point per lot
10
Allowed lot increment
0.01
Estimated round-trip cost per lot
0
Currency for all amounts
Euro (EUR)

Expected result

Position size (lots)
0.2
Worked example: Check Position size (lots)

Sample inputs demonstrate the method. They are not a forecast or product offer.

Account equity
5000
Account risk budget (%)
2
Stop distance in points or pips
30
Cash value per point per lot
10
Allowed lot increment
0.1
Estimated round-trip cost per lot
0
Currency for all amounts
Euro (EUR)

Expected result

Position size (lots)
0.3

Understanding your result

A zero lot result can mean the smallest permitted position would exceed the chosen risk amount. It does not mean the instrument has no risk.

Planned cash risk assumes the entered stop distance and costs. Slippage, price gaps, changing point values and broker rules can make realised losses different, so this is not a guaranteed loss limit.

Questions you might have

What does the result include?

Size a position from a cash-risk budget, stop distance and the value of one point or pip per lot.

Which limits should I check?

Provide contract specifications and a point value already converted to account currency.

Choosing the right inputs

Cash value per point per lot
Supply the cash value of one point or pip for one lot in the account currency. A contract's quoted pip value may require conversion before entry.
Stop distance in points or pips
Enter a positive stop distance in the same points or pips used by the cash-value input.
Allowed lot increment
Use the actual permitted lot increment. Rounding down avoids exceeding the entered budget under the model's cost assumptions.

Common mistakes to avoid

  • Do not enter a point value for one unit when the field is for one lot.
  • Leverage affects margin separately and is not a substitute for the stop-distance calculation.

Assumptions to check

  • Provide contract specifications and a point value already converted to account currency.
  • All calculations run on your device. Figures are scenarios based on your inputs, not investment recommendations.

Sources and method

Read our calculation and testing approach.