Futures Contract Size Calculator: Lot Size & Position Sizing

Futures position sizing runs on one line of arithmetic. Contracts equal your dollar risk divided by the cost of your stop on a single contract, where that cost is stop distance in ticks multiplied by tick value. Round down.

Risk per contract at common stop distances

This is the cost of a stop on one contract. Divide your dollar risk by the figure in the cell to get your contract count.

Risk per contract at common stop distances

If you would rather read the number off a table than use the calculator, this is the cost of a stop on one contract. Divide your dollar risk by the figure in the cell to get your contract count.

Risking $500 with a 30-tick stop on Micro E-mini S&P 500 futures means $37.50 per contract, so the position is 13 contracts. The same $500 and the same stop on E-mini S&P 500 futures costs $375 per contract, which allows 1 contract.

Contract size is set by the exchange and states what one futures contract controls. Lot size is the number of contracts a trader chooses to buy or sell. The exchange decides contract size and the trader decides lot size.

One Gold futures contract controls 100 troy ounces. That is the contract size, and no trader can change it. A trader who buys three Gold futures contracts has a lot size of three and controls 300 troy ounces.

Forex works differently and the two systems get confused constantly. Forex uses a standard lot of 100,000 units of the base currency, with mini lots at 10,000 units and micro lots at 1,000 units. Those sizes apply across every currency pair. Futures contract sizes are set individually per product, so an E-mini S&P 500 futures contract and a WTI Crude Oil futures contract have nothing structurally in common.

These are the CME Group specifications for the eight contracts retail and prop traders use most. Tick value is the number that matters for position sizing, because it converts stop distance into dollars.

Every micro is one tenth of its full-size contract

CME Group sizes each Micro E-mini contract at one tenth of its E-mini counterpart. Micro E-mini S&P 500 futures use a $5 multiplier against the $50 multiplier on E-mini S&P 500 futures. Micro E-mini Nasdaq-100 futures use $2, Micro E-mini Russell 2000 futures use $5, and Micro E-mini Dow futures use $0.50.

That ratio is the practical tool for anyone trading a small account. A 20-tick stop costs $200 on one WTI Crude Oil futures contract and $20 on one Micro WTI Crude Oil futures contract. Traders whose stop does not fit inside their risk limit should drop to the micro rather than tighten the stop into market noise.

Divide the dollar amount you are willing to lose by the cost of your stop on a single contract. The cost of the stop equals stop distance in ticks multiplied by tick value. Round the result down to a whole number.

Step 1: fix the dollar risk

Decide the loss you accept on this trade before looking at the chart. On a $50,000 evaluation account, a trader risking 1% has $500 available. Traders on funded accounts should work from the daily loss limit rather than the account balance, because the daily limit is the number that ends the account.

Step 2: measure the stop in ticks

Take the distance from entry to stop and convert it to ticks. E-mini S&P 500 futures move in 0.25-point ticks, so a stop 5 points away is 20 ticks. WTI Crude Oil futures move in $0.01 ticks, so a stop 30 cents away is 30 ticks.

Step 3: price the stop on one contract

Multiply ticks by tick value. A 20-tick stop on Micro E-mini S&P 500 futures costs $25 per contract at $1.25 per tick. The same 20-tick stop on E-mini S&P 500 futures costs $250 per contract at $12.50 per tick.

Step 4: divide and round down

A $500 risk divided by $25 per contract returns 20 contracts on Micro E-mini S&P 500 futures. The same $500 divided by $250 per contract returns 2 contracts on E-mini S&P 500 futures. Fractions always round down, because rounding up breaks the risk limit that started the calculation.

A prop firm lot size limit caps contract count regardless of what the risk math returns. Traders size to whichever number is lower, the risk-based figure or the firm cap. Breaching the cap can fail an evaluation on a trade that made money.

These caps change often and firms rarely announce them loudly. FundingPips introduced a 10 daily lot size limit, and Instant Funding replaced its margin rule with simple lot size limits. Both changes altered what a valid position looks like without changing anything about the market.

Check the cap on the firm's own rules page before sizing rather than trusting a comparison table. Our prop firm comparison tool puts two firms side by side on rules and pricing, and the guide to checking whether a prop firm is legit covers how to verify a rule against the legal terms rather than the marketing page.

Sizing from account balance instead of the daily loss limit

Funded accounts end on the daily loss limit, not on the balance. A $100,000 account with a $2,000 daily limit gives a trader $2,000 to work with that day, and three trades sized at 1% of balance put the account at the limit before the day is over.

Tightening the stop to fit more contracts

Moving the stop closer raises contract count and raises the chance the stop gets hit by ordinary noise. Traders who cannot fit a sensible stop inside their risk limit should switch to the micro contract instead of shrinking the stop.

Reusing a forex lot size habit on futures

Forex position sizing runs on pip value across a standard structure. Futures position sizing runs on tick value that differs product by product. A trader carrying a fixed contract count between E-mini S&P 500 futures and WTI Crude Oil futures is carrying completely different dollar risk.

Ignoring the cap until after the trade

Firm caps are checked automatically and breaches are logged whether or not the trade was profitable. Confirm the cap before entry, since no result after the fact reverses a rule breach.