What EUR/USD means
EUR/USD expresses how many US dollars are needed for one euro. EUR is the base currency; USD is the quote currency. A hypothetical price of 1.1000 therefore means 1 euro buys 1.10 dollars. If the rate moves to 1.1020, the euro has appreciated against the dollar. This explains the quotation, rather than suggesting a trade.
From price to pips
For EUR/USD, one pip is 0.0001. A move from 1.1000 to 1.1020 is 20 pips: the price difference, 0.0020, divided by 0.0001. A fifth decimal place represents a fraction of a pip and does not change this convention. Confusing a pip with the last decimal place can multiply the calculated position size by ten.
A pip measures movement. To convert it into money, you need the quantity traded and the currency in which you read the result. In the standard Forex model, one lot is 100,000 units of the base currency. For EUR/USD, 100,000 × 0.0001 = 10 USD per pip per lot.
A position sizing example
Consider a hypothetical balance of 10,000 USD, a risk budget of 1% and a stop 20 pips away. The budget is 100 USD. One lot loses 200 USD over that move before costs: 20 pips × 10 USD. The mathematical position size is therefore 100 ÷ 200 = 0.50 lots, or 50,000 euros of base currency.
This example excludes commissions, gaps and slippage. Adding costs increases risk per lot and reduces the position size that fits the budget. If the account is in EUR, convert pip value from USD to EUR; simply changing the currency symbol beside the result is not enough.
Making EUR/USD tests comparable
Before comparing two versions of the same strategy, keep the period, data, timeframe, costs and execution rules consistent. Record the time zone used to define your sessions and account for daylight saving changes: an ambiguous time filter can select different trades.
Changing the stop, risk and entry conditions together makes it difficult to attribute the result to one specific decision. Define the variation first, run the test and compare drawdown, trade count and the distribution of results as well as the final balance.
Three checks before using the result
- Confirm that the broker uses the contract size and minimum volume step assumed in the calculation.
- Check whether spreads and commissions are already included in prices or must be added, without counting them twice.
- Keep stop risk separate from the required margin: position size does not show that the account has sufficient margin.
The Lot Calculator lets you repeat this calculation with different balances, stops and costs. It helps you check assumptions; it does not guarantee execution at the stop price or future results.
