Here is how to calculate lot size step by step. The previous article covered “1 lot is a contract specification.” This one goes one level deeper: once you know the specs, how many lots should you actually trade?

Here’s the conclusion up front:

It’s not about how much you want to trade — it’s your stop-loss that determines how much you can trade.

And the result is often counter-intuitive: with the same money and the same risk cap, switching instruments can change how many lots you can trade by several times over.

Price Reference

All figures in this article are calculated using 2026-08-18 market prices:

Recalculate if prices change. Contract specifications follow whatever your platform publishes.

Level 1: How Much Is 1 Lot Actually Worth

First, convert “1 lot” into an actual dollar amount:

At the same “1” lot, gold’s exposure is 4.4x that of USD/JPY. This is a direct application of the formula from the previous article:

Notional Value = Lot Size x Contract Size x Price

Level 2: How Much You Gain or Lose Per Tick

Notional value tells you your exposure, but what actually determines your P&L is the pip/tick value — how much one lot gains or loses for every smallest price move.

For the same one-tick move, gold moves 10x as much as EUR/USD.

That’s arithmetic, not a judgment call. It doesn’t mean gold is riskier — it just means the same-sized price move produces a different dollar swing, so you can’t reuse the same lot size across instruments.

Level 3: How Many Lots Can $10,000 Actually Trade

This is the core of this article. Flip the order: decide how much you can afford to lose first, then work backward to lot size.

Lot Size = Acceptable Loss / (Stop Distance x Value Per Tick)

Assume a $10,000 account, risking a maximum of 2% per trade, i.e. $200. Stop distances are set at typical magnitudes for each instrument (these are illustrative assumptions — substitute your own actual settings):

EUR/USD: 0.67 lots. Gold: 0.10 lots — a 6.7x difference.

Same account, same risk cap — just switch the instrument, and the tradable lot size changes this much. If you reused the same lot size across all three instruments, you’d be taking on completely different risk on two of them.

A Counter-Intuitive Point

0.10 lots of gold sounds tiny. But the notional value of that position is:

0.10 x 100 oz x 4,400 = $44,000

That’s 4.4x your account balance. A small lot size doesn’t mean small exposure.

Having Enough Margin Is Not the Same as Having Enough Risk Capacity

Using ESMA retail leverage caps as an estimate (30:1 for major pairs, 20:1 for gold), the margin required for the three positions above totals roughly $7,400 — which a $10,000 account can technically “afford.”

But being able to afford it isn’t the same as being able to trade it in full. Margin determines whether you can open the position; your stop-loss determines how much you can afford to lose — these are two different things. Using margin as your position-size ceiling means managing risk with a number that has nothing to do with risk.

Further reading: How Much Is 1 Lot? Shares, Contracts, and Lots – What Does the “1” in Your Order Box Actually Mean?

How to Do This in Practice

Rerun these three steps every time you switch instruments:

1. Check the tick value: what’s the smallest tick for this instrument, and how much does one lot move per tick
2. Set your stop-loss: where’s the stop for this trade, how many ticks away from entry
3. Work backward to lot size: Acceptable Loss / (Stop Distance x Value Per Tick)

The number you get is usually smaller than what you originally wanted to trade. That’s not being overly cautious — it’s turning risk into a number you decided on in advance, instead of one you discover after the fact.

Frequently Asked Questions

What’s the correct way to calculate lot size?

Work backward using “Acceptable Loss / (Stop Distance x Value Per Tick).” First decide the maximum you can afford to lose on this trade, then look at the stop distance and the instrument’s tick value — the result is the lot size you should trade.

Why can the same amount of money trade different lot sizes across instruments?

Because each instrument’s “value per tick” is different. Based on 2026-08 prices, one lot of EUR/USD moves $10 per tick, while one lot of XAU/USD moves $100 per one-dollar move — a 10x difference. So under the same loss cap, the tradable lot size also differs significantly.

How much risk should I take per trade?

This article uses 2% as an example — a common discussion benchmark, not a recommendation. The actual figure depends on your capital, trading frequency, and strategy characteristics, and should be decided by you.

How do I look up the tick or pip value?

Your trading platform’s instrument specification page usually shows the minimum tick size and tick value. Specs for the same instrument can differ between platforms, so use whatever your platform publishes.

If I have enough margin, can I trade the full size?

No. Margin determines whether you can open the position; your stop-loss determines how much loss you can withstand. Having enough margin doesn’t mean you can handle the risk — lot size should be decided by your stop-loss, not by your margin.

Conclusion

The previous article said “check the specs before you trade a ‘1.’” This one says “calculate your lot size after you’ve checked the specs.”

Together, these two make up a complete pre-trade checklist. Getting your direction wrong is a matter of probability. Getting your lot size wrong means every single trade is built on the wrong baseline.

Calculate first. Trade second.

Risk Disclosure: CFDs are high-risk financial instruments that can result in the rapid loss of money. Past performance does not guarantee future results, and all strategies and backtests are for reference only and do not constitute investment advice. Please fully understand our Risk Disclosure before trading.