A forex lot is a standardized number of currency units in a single trade. One standard lot is 100,000 units of the base currency, and brokers offer smaller fractions so any account size can trade responsibly. The lot you choose sets what each pip of movement is worth in dollars.
The four lot sizes
Lot sizes step down by a factor of ten. That makes the dollar value of a pip easy to remember once you know the standard-lot figure:
These pip values assume a USD account trading a pair where USD is the quote currency, such as EUR/USD. On other pairs the exact figure shifts, which is why calculating pip value for your specific pair matters.
Why lot size is really a risk decision
Beginners often pick a lot size first and discover their risk second. Professionals do the opposite. You decide how many dollars you are willing to lose on the trade, measure your stop distance in pips, and let those two numbers tell you the lot size. Lot size is the output of a risk plan, not a guess.
Lot size = dollar risk / (stop distance in pips x pip value per lot)
Notice the dollar risk is identical in all three rows. Only the lot changes, because a wider stop needs a smaller position to keep the same money on the line. This is the whole idea behind position sizing.
Which lot size should you trade?
- Small or new account - micro or nano lots, so a full stop loss costs a few dollars while you build the habit.
- Growing account - mini lots once your risk per trade in dollars justifies them.
- Larger, proven account - standard lots or fractions of them, always sized from a fixed percentage of risk.
Important: the goal is never to trade the biggest lot you can afford. It is to trade the lot that keeps each loss at your planned percentage. A trader with a $500 account and micro lots can be far safer than one with $10,000 and reckless standard lots.
Test lot sizing before it costs real money
The safest place to feel how lot size scales your wins and losses is a backtesting simulator. When you replay charts and place trades, the tool sizes the position for you from your chosen risk, so you can watch how a 20-pip stop and a 100-pip stop produce very different lots for the exact same dollar risk. Seeing that connection a hundred times is what makes correct sizing automatic when real money is on the line.
Forex lot size FAQ
What is a lot in forex?
A standardized bundle of currency units. One standard lot is 100,000 units of the base currency; a mini is 10,000, a micro is 1,000, and a nano is 100 units.
How much is a pip worth per lot?
Roughly $10 per standard lot, $1 per mini, $0.10 per micro, and $0.01 per nano on four-decimal pairs with a USD account and USD as the quote currency. The exact value depends on the pair.
What lot size should a beginner use?
Micro lots or smaller, sized so a full stop risks about one percent of the account. Decide the dollars you can lose first, then let position sizing pick the lot.