What Is Contract Size in Forex?
Contract size refers to the total number of base currency units in a forex position. Brokers standardize trades into lots to simplify execution. A standard lot is 100,000 units of the base currency. A mini lot is 10,000 units. A micro lot is 1,000 units. Knowing your contract size tells you exactly how much currency you control.
The Contract Size Formula
Contract Size = Number of Lots × Units per Lot
Lot type determines the units per lot:
- Standard lot: 100,000 units
- Mini lot: 10,000 units
- Micro lot: 1,000 units
Position value in USD = Contract Size × Exchange Rate. For 1 standard lot of EUR/USD at 1.0850: 100,000 × 1.0850 = $108,500.
Step-by-Step: EUR/USD Example
You want to trade 2 mini lots of EUR/USD at 1.0850 with a 20-pip stop loss.
- Step 1 — Contract size: 2 × 10,000 = 20,000 units
- Step 2 — Position value: 20,000 × 1.0850 = $21,700
- Step 3 — Pip value per lot: 10,000 × 0.0001 = $1.00
- Step 4 — Total pip value: 2 × $1.00 = $2.00 per pip
- Step 5 — Dollar risk: 20 pips × $2.00 = $40
Step-by-Step: USD/JPY Example
You want to trade 1 standard lot of USD/JPY at 150.00 with a 30-pip stop loss.
- Step 1 — Contract size: 1 × 100,000 = 100,000 units
- Step 2 — Pip size for JPY pairs: 0.01 (not 0.0001)
- Step 3 — Pip value in JPY: 100,000 × 0.01 = 1,000 JPY per pip
- Step 4 — Pip value in USD: 1,000 / 150.00 ≈ $6.67 per pip
- Step 5 — Dollar risk: 30 pips × $6.67 = $200.10
Contract Size vs. Position Size vs. Lot Size
These three terms are related but distinct. Lot size is the quantity category (standard, mini, micro).Contract size is the actual number of units, calculated from lots × units per lot.Position size is a broader term referring to how many lots or units to trade given your account risk rules. Position sizing answers how many lots; contract size tells you how many units those lots represent.
How Leverage Affects Contract Size
Leverage does not change your contract size — it changes how much margin you need to hold the position. At 100:1 leverage, a $108,500 standard lot position requires only $1,085 margin. Your pip value, dollar risk, and potential profit or loss are determined by contract size and stop loss, not leverage level.
Use Our Free Contract Size Calculator
Skip the manual math. Enter your lot type, number of lots, currency pair, and exchange rate in the contract size calculator to get instant results for total units, pip value, and position value. For pip value lookups, use the pip value calculator.
Frequently Asked Questions
What is the formula for contract size in forex?
Contract Size (in units) = Number of Lots × Units per Lot. Standard lot = 100,000 units, mini lot = 10,000 units, micro lot = 1,000 units. For 2 mini lots: 2 × 10,000 = 20,000 units.
How does lot type affect my contract size?
Lot type determines the base unit size. A standard lot is 100,000 currency units; a mini lot is 10,000; a micro lot is 1,000. If you trade 3 standard lots, your contract size is 300,000 units. Smaller lots reduce both position size and pip value proportionally.
What is the contract size for EUR/USD standard lot?
One standard lot of EUR/USD equals 100,000 euros. At an exchange rate of 1.0850, the position value is 100,000 × 1.0850 = $108,500. The pip value is 100,000 × 0.0001 = $10 per pip.
How do I calculate contract size for JPY pairs?
The lot unit sizes are the same (standard = 100,000). However, pip size is 0.01 for JPY pairs (not 0.0001). Pip value per standard lot = 100,000 × 0.01 = 1,000 JPY. To convert to USD, divide by the current USD/JPY rate. At 150.00: 1,000 / 150 ≈ $6.67 per pip.
What lot size should a beginner use?
Beginners should start with micro lots (1,000 units). A micro lot of EUR/USD has a pip value of only $0.10, meaning a 20-pip stop loss risks just $2. This allows learning with real money while keeping financial risk minimal.
How does leverage affect contract size?
Leverage does not change contract size — it changes the margin required to hold the position. With 100:1 leverage, a standard lot position ($100,000 contract size) only requires $1,000 margin. Your risk and pip value are determined by contract size, not leverage.
Can I calculate the exact units without using lot sizes?
Yes. Some brokers (especially ECN/STP brokers) allow you to specify units directly without using lot fractions. If you want to risk $50 on EUR/USD with a 20-pip stop, you need $50 / (20 × 0.0001) = 25,000 units, which is 2.5 mini lots or 0.25 standard lots.
What is the minimum contract size at most forex brokers?
Most retail forex brokers offer a minimum of 0.01 lots (1 micro lot = 1,000 units). Some brokers offer nano lots (100 units). For trading platforms like MetaTrader 4/5, the minimum is typically 0.01 lots and increases in 0.01 increments.