Position Size by Instrument: Contract Size, Pip Size and Unit Step

Take one account of 10,000 USD, one budget of 1% (100.00 USD), and put the same trade idea on seven different instruments. Every one of them loses exactly 100.00 USD if its stop is hit — and every one of them needs a completely different order size to do it:

Nothing about the setup changed. Only three numbers per instrument changed, and those three numbers are why a size that is conservative on one symbol is reckless on another.

The three numbers that decide your size

Contract size is how many units sit inside one lot. It is 100,000 for a forex pair, 100 for XAU/USD, 5,000 for XAG/USD, 1,000 for WTI/USD, and 1 for most indices and crypto pairs. Lots are a display convention; losses are paid per unit, so the contract size is what converts a number you can compare across platforms into a number your broker will accept.

Pip size is the price increment the instrument quotes in, and it is not 0.0001 everywhere. Every JPY pair uses 0.01. Silver uses 0.001. An index quotes whole points, so its pip size is 1. Get this wrong and a "20 pip stop" is twenty of something completely different on another symbol.

Unit step is the smallest increment your broker accepts. Forex pairs will usually take 1,000 units (0.01 lots); gold and indices step in whole units; crypto steps in fractions (0.001 BTC is common). The step is the reason a computed size that is not a multiple of it has to be rounded down — rounding up spends risk you did not budget.

Why the same percentage produces wildly different position values

Look again at the table above: EUR/USD puts 55,000 USD of notional behind a 100.00 USD risk, while gold puts 120,000 USD behind the same 100.00 USD. Neither trade is bigger than the other in risk terms. They differ because the gold trade's stop is 2.00 dollars wide on a 2,400 dollar price — 0.08% of the price — while the EUR/USD stop is 0.0020 wide on 1.1000, roughly 0.18% of the price.

The consequence is the part that surprises people: a tight stop in price terms buys you more units, and more units mean more notional. If you size by looking at the position value and thinking "that is too much exposure", you will cut the trades that are actually correctly sized, and keep the ones that are not.

The right order is always: fix the stop first for the chart, convert it to a distance, pay the budget against that distance, then look at the resulting notional and ask whether margin and exposure limits still allow it.

Specifications by asset class

A representative slice from the 131 instruments in our reference table. Quote currency matters twice: it sets what your loss is denominated in, and it decides whether a conversion rate is needed to express it in your account currency.

The 131 rows break down as 67 forex pairs, 43 crypto pairs, 12 indices, 4 metals, 3 energies, plus a stock row and a custom row you can point at any unlisted instrument.

What one tick is worth, instrument by instrument

A tick value is the one line that turns a price move into money, and it is why a size that looks tiny on one instrument is enormous on another. Multiply the two columns above:

Everything called a commodity position size calculator, an oil lot size calculator, a silver lot size calculator or an index position size calculator — up to and including a Nasdaq position size calculator, which in this dataset is the row published as USTEC — is that third line run with a different pair of columns filled in.

Three things follow from that table, and each one changes a size. Silver pays five times what gold pays per pip because its contract is fifty times larger while its pip is ten times smaller. Oil and natural gas pay the same ten dollars per pip, but a whole dollar of price moves one lot of WTI by 1,000.00 and one lot of natural gas by 10,000.00, which is why an oil trade and a gas trade at the same risk budget are very different numbers of lots. And on an index contract one pip is a whole index point paying 1.00, so the size has to be counted in whole contracts — the arithmetic the futures position size calculator runs in full.

These figures come from the same published rows as the tables above; contract sizes and increments differ between brokers and between account types, so check your own specification before using any of them. A number computed here is only ever as good as the two columns behind it.

Gold, worked end to end

Gold is where the contract column bites hardest, so it is worth walking the whole way through. The first thing to unlearn is the word "pip": XAU/USD is quoted directly in dollars per ounce — 2,650.00 — and the smallest increment brokers normally quote is 0.01, one cent of an ounce. The second thing is the contract: in this reference data one contract of gold is 100 ounces, against 100,000 units for a forex pair. Those two facts fix every number that follows.

There is no pip conversion and no quote-currency rate for XAU/USD on a USD account: entry, stop and spread are already in dollars, and the answer comes out in ounces. Divide by 100 to get lots.

Worked example: 1% of a 10,000.00 USD account

Account 10,000.00 USD, risk 1% (100.00 USD). Gold is at 2,650.00 and the stop sits at 2,642.00, eight dollars away. The broker's spread on gold is 0.40, so the effective distance to the stop is 8.40.

1. Effective stop distance: 8.00 + 0.40 = 8.40 USD.
2. Ounces: 100.00 / 8.40 = 11.90 ounces.
3. Round down to the step: one ounce, so 11 ounces = 0.11 contracts.
4. Worst case at the stop: 11 x 8.40 = 92.40 USD. Inside the 100.00 budget.

The spread is not a rounding detail on gold. Gold spreads are wider than major forex pairs and they widen further around data releases, so a distance that is eight dollars at midday can be twelve at the open. Note also how coarse a one-ounce step is at this size: 11 and 12 ounces are a nine percent difference in exposure and there is nothing in between. On a small account that step is the whole trade — the small account guide works through that problem.

Why gold sizes look small next to forex

Comparing the two in lots is what makes them look different; comparing them in dollars at risk is what makes them the same trade. Turning a lot count into units, notional and margin — and turning an amount you are willing to lose back into a lot count — is what the lot size calculator does, and it is the same arithmetic for XAU/USD as for EUR/USD once the contract size and the tick are filled in.

Because the contract is 100 units instead of 100,000. A forex standard lot is six figures of currency; a gold contract is two figures of metal. A 1.00 move on gold costs 100.00 USD per contract, while a comparable 100-pip move on EUR/USD costs 1,000.00 USD per standard lot — but a 100-pip move is a large forex day and a 1.00 move in gold is an ordinary one. Compare them in dollars at risk and they are the same trade; compare them in lots and gold looks tiny.

• Do not reuse a forex lot habit. "One lot" means a hundred ounces here, and that is a large position.
• Contract specifications vary by broker. This reference data uses 100 ounces with a one-ounce step; some brokers offer a 10-ounce mini or a 1-ounce micro, and some express gold in different units entirely.
• Silver is not gold. In the same data XAG/USD is 5,000 ounces per contract with a 0.001 tick, so a 0.001 move is 5.00 USD per contract — a different scale, the same formula.
• Gold gaps. A stop eight dollars away is not a guarantee of an eight-dollar loss; weekend gaps and news spikes can exceed it, and no position size protects against that.

Gold swings read differently on a chart than in a quote window, and the stop distance is easier to judge in dollars there. We pull XAU/USD up in TradingView before deciding on an ounce count.

The four mistakes this table kills

• Assuming 100,000 everywhere. One lot is 100 oz of the same size contract that gives 5,000 oz of silver. Sizing "one lot" on silver because one lot is normal on EUR/USD multiplies the risk by fifty.
• Using 0.0001 as the pip for every pair. On USD/JPY a 0.20 move is 20 pips, not 2,000. Sizing tools that hardcode 0.0001 produce sizes that are off by a factor of one hundred on every JPY cross.
• Ignoring the unit step. A computed size of 17,400 units is not sendable on a 1,000-unit step instrument; 17,000 is. The 400 units you drop also drop a little of your risk, which is the right direction to err.
• Forgetting the quote currency. A loss priced in JPY or CAD is not a loss in USD until it is converted. Skip the conversion and every size on a cross pair is wrong by whatever the rate happens to be that day.

Checklist before you send the order

• Confirm the stop in price terms for the chart first; do not pick a size and then invent a stop that fits it.
• Check the instrument's pip size so the stop distance means what you think it means.
• Pay the budget against the distance, then round down to the unit step.
• Convert the result into lots with the contract size, so it matches what your order ticket asks for.
• Only then check the notional against your exposure limit and your margin.
• Verify the three numbers against your broker's own specification sheet — ours is what the tool assumes, not what every broker deals.

Pip size and step size only become real once you look at the chart you are trading. To measure a stop distance before touching the size, we keep TradingView open on a second screen.

Open the position size calculator

Questions traders ask

It is how many units sit inside one lot, and it varies wildly: 100,000 for a forex pair, 100 for XAU/USD, 5,000 for XAG/USD, 1,000 for WTI, 1 for most indices and crypto pairs. Losses are paid per unit, so the contract size converts a number you can compare across platforms into one your broker will accept.

No, and getting this wrong is expensive. Every JPY pair quotes 0.01, silver quotes 0.001, and indices quote whole points, so their pip size is 1. A "20 pip stop" means twenty of something completely different once you move between those groups.

Because stop width as a share of price differs. In the example above, EUR/USD puts 55,000 USD of notional behind a 100.00 risk while gold puts 120,000 behind the same 100.00 — gold's stop is 0.08% of price against EUR/USD's roughly 0.18%. Same risk, different notional, neither trade bigger.

Brokers accept increments, not arbitrary numbers. Forex usually steps in 1,000 units, gold and indices in whole units, crypto in fractions such as 0.001 BTC. Rounding down keeps you inside budget; rounding up spends risk you never budgeted, even when the platform quietly accepts it.

With a 200-point stop, no. One US30 contract is one unit, so the stop costs 200.00 on a single unit — 2.00% of a 10,000.00 account, twice a 1% budget. The division gives 100.00 ÷ 200.00 = 0.50 units and the step is one whole unit, so the answer is nothing to send rather than a smaller number; that is a trade that does not exist at this budget, not a rounding loss. Set the stop at 50 points and the same 100.00 buys 2.00 units for exactly 100.00. BTCUSDT runs the other way: one unit per lot as well, but a 0.001 step leaves 0.200 units of a 500.00 stop inside the same budget.

Pip size multiplied by contract size, for one lot. From the rows published above: silver pays 0.001 × 5,000 = 5.00 a pip as against gold's 0.01 × 100 = 1.00; WTI and natural gas both pay 10.00 a pip; every index row pays 1.00 for one whole point, which is also one contract. The size then comes from dividing your budget by the stop distance times the contract size, so knowing the tick value is knowing half of that.

Risk sizing. Fix the stop for the chart, convert it to a distance, pay the budget against that distance, and only then look at the resulting notional against margin and exposure limits. If you start from position value and cut whatever "looks too big", you end up cutting the correctly sized trades and keeping the wrong ones.

How do I calculate position size for gold (XAU/USD)?

Divide the risk budget by the stop distance plus the spread, both in dollars: 100.00 / (8.00 + 0.40) = 11.90 ounces, rounded down to 11. There is no pip conversion to do on a USD account, because entry, stop and spread are already quoted in dollars per ounce, and the answer comes out in ounces rather than in lots.

Is one lot of gold 100 ounces?

In the reference data this site uses, yes — 100 ounces per contract with a one-ounce minimum step. Brokers are not consistent about it: some quote a 10-ounce mini and a 1-ounce micro, and some express gold in units other than ounces entirely. Check your own specification before trusting any ounce count produced here, because getting the contract wrong by a factor of ten is a normal way to blow a budget.

Why does my gold size look so much smaller than my forex size?

Because the contract is 100 units instead of 100,000. A 1.00 move in gold costs 100.00 USD per contract, so eleven ounces already carries about eleven dollars of loss per dollar of price movement. Forex looks bigger only because its unit is smaller; compare them in dollars at risk and the two are the same trade.

Related guides

• How to calculate position size in forex — the single-instrument version of the same formula.
• Reference data — contract size, pip size and unit step for all 131 instruments.
• Forex profit calculator — what the spread and commission do to a result once the size is fixed.
• Adding to a position — splitting one budget across several entries.
• Portfolio risk limits — summing exposure across instruments whose contract sizes differ.
• Futures position size calculator — the twelve index rows turned into a contract count, including how much budget whole-contract rounding strands.