What Is Lot Size in Forex? | What Are Forex Signals?

Lot size is the amount of currency you buy or sell in a forex trade. A standard lot is 100,000 units of the first currency in the pair, a mini lot is 10,000 and a micro lot is 1,000.

The three common sizes

Lot	Units of base currency	Platform shows	Pip value on EUR/USD
Standard	100,000	1.00	$10.00
Mini	10,000	0.10	$1.00
Micro	1,000	0.01	$0.10

On trading platforms such as MetaTrader, sizes are entered in standard lots, so 0.25 means a quarter of a standard lot, or 25,000 units. Some US brokers quote sizes in units instead.

Why lot size matters more than the signal

A signal gives you a pair, a direction, an entry, a stop loss and a take profit. It does not, and should not, choose your lot size. That one number decides:

Your dollar risk. Pips at risk × pip value. A 30-pip stop costs $300 at 1.00 lot and $3 at 0.01.
Your margin. One standard lot of EUR/USD at 1.0850 is about $108,500 of currency. At the US minimum of 2% margin for major pairs, it ties up about $2,170.
Your effective leverage. That same lot in a $5,000 account is about 22 times the account’s value.

The margin rules are covered in leverage and margin in forex.

Sizing a lot from your risk

The usual approach works backwards from the money you are willing to lose:

Lot size = (account × risk %) ÷ (stop distance in pips × pip value per standard lot)

For a $10,000 account risking 1% on a 25-pip stop on EUR/USD:

Dollars at risk: $10,000 × 1% = $100
Needed pip value: $100 ÷ 25 pips = $4 a pip
Lot size: $4 ÷ $10 = 0.40 lots

A trader who copies “1 lot” from a signal group regardless of account size is, in effect, letting the provider choose their risk. The full method is in pips, lots and signal math, and the longer-run maths of sizing is in position sizing and the Kelly criterion.

What to watch for

Copy-trading multipliers. Copy platforms may scale a leader’s size to your account by a ratio you choose. A setting that looks small can still mean high leverage.
Lot size in non-USD pairs. For USD/JPY or USD/CAD, the pip value per lot is not $10, so the same lot size carries a different dollar risk.
Minimum sizes. Some brokers’ minimum trade is a mini lot, which may be too large for a small account to follow a signal with a wide stop.