One formula, every instrument
Position sizing looks like it needs a different recipe per asset class. It does not. There is one equation, and everything else is a parameter:
lots = risk ÷ (stop distance × contract size × rate)
Risk is what you are willing to lose, in your account currency. Stop distance is entry minus stop, in price. Contract size is how many units of the thing one lot carries. Rate converts the quote currency into your account currency, and is simply 1 whenever they already match.
Run the same $100 of risk through four very different instruments and the only column that moves is the contract size:
| Symbol | Contract size | Stop | Per 1.00 move | Lots |
|---|---|---|---|---|
| EURUSD | 100,000 EUR | 0.0020 (20 pips) | $100,000 | 0.50 |
| USDJPY | 100,000 USD | 0.20 (20 pips) | ¥100,000 ≈ $667 | 0.75 |
| XAUUSD | 100 oz | 3.50 | $100 | 0.28 |
| XAGUSD | 5,000 oz | 0.25 | $5,000 | 0.08 |
$10,000 account, 1% risk. USDJPY assumes a rate of 150.00.
Where gold and silver trip people up
Ask five brokers what a pip is on XAUUSD and you will get three answers: 0.01, 0.10, or a full dollar. That is not a rounding disagreement — it is a factor of a hundred between the extremes. So when a calculator asks you for "stop loss in pips" on gold, it has silently picked one of those definitions on your behalf, and if it picked differently from your broker your position comes out an order of magnitude off.
The fix is to stop treating pips as an input. Your chart shows you a price, and the distance between two prices is a fact no broker can redefine. That is what this calculator takes. It still reports the pip value once the position is sized, because that number is useful — but as an output, derived from a contract size you can see and correct. If the pip value itself is what you are after, our pip value calculator works that side directly, and shows all three gold conventions rather than choosing one.
Silver adds a second trap. A standard lot is 5,000 troy ounces at most brokers, so a one-cent move on one lot is $50 — but some brokers run 1,000 or 2,500 ounce contracts, and nothing on the chart tells you which. That is exactly why contract size is an editable field here instead of a constant baked into the code.
Getting the exact numbers from MetaTrader 5
Everything the calculator needs about your broker sits in one panel. In MT5, open Market Watch, right-click the symbol, and choose Specification. Read off:
- Contract size — units in 1.00 lot.
- Volume step / minimum / maximum — the tradable granularity.
- Tick size and tick value — the broker's own price-to-money conversion, already expressed in your deposit currency.
If you enter that last pair into the Exact override box, the calculator uses your broker's arithmetic directly rather than reconstructing it, and the conversion rate stops mattering at all. It is the most accurate route available, and it is the one no generic web calculator offers you.
Common questions
Is the lot size for gold calculated differently from forex?
No. The formula is identical. What changes is the contract size: one forex lot is 100,000 units of the base currency, one gold lot is 100 troy ounces, and one silver lot is usually 5,000 troy ounces. Put the right contract size in and the same arithmetic sizes every instrument.
Why does this ask for a stop-loss price instead of pips?
Because there is no agreed pip on gold. Some brokers treat 0.01 as a pip, some 0.10, some a full dollar — a threefold spread of definitions on the same symbol. A calculator that takes pips has to pick one and hope. A price distance is never ambiguous, so that is what we take. We still show you the pip value afterwards, as an output.
What is a standard lot of silver?
5,000 troy ounces at most brokers, matching the COMEX contract, though some use 1,000 or 2,500. At 5,000 oz a one-cent move on one lot is $50. Because this genuinely varies, the contract size is an editable field here rather than a hidden constant.
Do I need a live exchange rate?
Usually not. If the quote currency is your account currency the rate is 1. If the base currency is your account currency — USDJPY on a USD account — we derive it from your entry price. Only a true cross, such as EURGBP on a USD account, has to ask, and you can read that rate off your platform.
Why is the result rounded down?
Rounding to the nearest lot step would push the position past the risk budget you just typed in. A sizing tool should never do that silently, so we always round down and tell you how much of the budget went unused.
This calculator is an educational tool. It does not know your broker, your account, or your strategy, and it is not investment advice or a recommendation to place any trade. Position sizes are only as accurate as the specification you enter — confirm against your own platform before you trade. See the full Risk Disclosure.