A wider stop loss changes how much a trade can lose. Keeping the same lot size after moving the stop therefore changes your planned risk. This tutorial explains the calculation and a visual workflow for manual traders using MetaTrader 5.
Disclosure: I am the developer of Trade Assistant Risk Calculator MT5, the tool used below. The example is illustrative, not a live trading result or a trade recommendation.
1. Convert the percentage into a money budget
Suppose your balance is USD 5,000 and you choose a 1% risk budget for one trade:
USD 5,000 × 0.01 = USD 50 of planned risk.
You can also use equity as the reference, but balance and equity may differ when you have open positions. Choose the reference deliberately. The 1% figure here is an example, not a recommended risk level for every trader.
2. Calculate the loss at the planned stop
For a simplified EURUSD example, assume a USD account, a standard 100,000-unit contract, a 20-pip entry-to-stop distance and a pip value of USD 10 per pip for one lot.
One lot would have a planned price loss of 20 × USD 10 = USD 200. Ignoring transaction costs, the position size would be:
USD 50 ÷ USD 200 = 0.25 lots.
If the stop distance increases to 40 pips, one lot's planned price loss becomes USD 400, giving a raw size of 0.125 lots. With a 0.01-lot volume step, rounding down to 0.12 lots keeps this simplified price-loss estimate below USD 50. Rounding up to 0.13 would exceed it.
Always check your broker's symbol specifications. Contract size, tick size, tick value, account-currency conversion, minimum volume and volume step can differ. Do not apply the EURUSD pip-value assumption to gold, indices or other instruments.
3. Include costs and execution limits
Commission uses part of the risk budget. Entry and stop calculations should also reflect the relevant Bid/Ask prices and spread. Slippage and gaps can make realized losses larger than the planned amount, and a stop order does not guarantee its execution price.
Margin is a separate check: having enough margin to open a position does not mean its stop-loss risk is suitable. Multiple open positions also create combined exposure that a single-trade calculation does not describe.
4. Plan the trade visually in MT5
Trade Assistant Risk Calculator MT5 lets you plan a manual trade using Entry, Stop Loss and Take Profit lines on the chart. To try the basic workflow:
- Install the Demo on an MT5 demo account and attach it to a chart. Enable Algo Trading so the EA can place and manage demo orders.
- Turn LOT CALC on, select the % Balance risk mode and enter 1.0 for this example.
- Set your planned entry and stop-loss prices using the chart lines.
- Move the stop-loss line and observe the lot-size calculation change with the new distance.
- Set the take-profit line and review the displayed risk-to-reward ratio.
- Select the intended market or pending-order mode. Keep order confirmation enabled and review the lots, risk, margin and prices before submitting a demo order.
The product also offers commission-inclusive lot sizing using an estimate from account history. Treat that estimate as an input to planning, not a guarantee of the final transaction cost or loss.
After the basic workflow is familiar, you can explore partial closing, automatic breakeven and trailing stops. Start with one feature at a time so you understand its settings and behavior.
5. Try the workflow before buying
The free Demo is valid for 30 days from its first run on each terminal and blocks live accounts. Use a demo account to evaluate the interactive chart workflow.
- Demo download and installation
- Complete user guide
- Trade Assistant Risk Calculator MT5 — product page
The goal is to make position-size planning easier to inspect and repeat. The tool helps with calculation and execution management; it does not select profitable trades or guarantee a risk limit will hold under all market conditions.
Which part of position sizing takes you the most time: checking symbol values, adjusting lots after moving the stop, or managing the position after entry? Share your workflow or a question in the comments.
