Before you can manage risk properly, you need to know exactly how much money is on the line for a given price move. That comes down to two building blocks: the pip and the lot. Once you understand how they combine, position sizing becomes simple arithmetic instead of guesswork.
What Is a Pip?
A pip is the standard unit of price movement in forex. For most pairs it's the fourth decimal place, so a move from 1.0850 to 1.0851 is one pip. For pairs involving the Japanese yen, it's the second decimal place, since the yen has far less value per unit than currencies like the euro or dollar.
What Is a Lot?
- ▸A standard lot equals 100,000 units of the base currency.
- ▸A mini lot equals 10,000 units, one-tenth of a standard lot.
- ▸A micro lot equals 1,000 units, one-hundredth of a standard lot.
- ▸Most retail brokers also allow custom lot sizes down to 0.01 lots.
Calculating Pip Value
Pip value depends on the lot size and the currency pair. For a standard lot of a pair where the US dollar is the quote currency, such as EUR/USD, one pip is worth approximately $10. For a mini lot it's about $1, and for a micro lot about $0.10.
Pip value = (pip size / exchange rate) × lot sizeFor pairs where the quote currency isn't the dollar, or where your account currency differs from the quote currency, the pip value has to be converted using the current exchange rate, which is why brokers usually display it automatically in the platform.
Worked Example
Say you trade one standard lot of EUR/USD and the price moves 25 pips in your favor. At roughly $10 per pip, that's a $250 gain. If you'd traded 0.10 lots instead, the same 25-pip move would be worth about $25.
Using This for Position Sizing
Position sizing works backward from your risk tolerance. Decide how much money you're willing to risk on the trade, divide by the stop-loss distance in pips, and that tells you the pip value you can afford — which in turn tells you the lot size to use.
Lot size = (account risk in money / stop-loss in pips) / pip value per lotMost trading platforms include a position size calculator that takes your risk amount, stop-loss distance, and pair, and outputs the correct lot size. Use it, but understand the underlying math so you can sanity-check the result.
Common Mistakes
- 1.Confusing lot size with risk amount — a bigger lot always means bigger pip value, regardless of stop distance.
- 2.Forgetting that yen pairs use a different pip decimal place, leading to sizing errors.
- 3.Not accounting for currency conversion when your account currency differs from the pair's quote currency.
Getting comfortable with pip and lot math removes one of the biggest sources of accidental over-leveraging in new traders' accounts. It's a small amount of arithmetic that pays for itself many times over in risk control.