SPX500 lot size calculator
A standard SPX500 lot is 1 contract, quoted to 2 decimals, and one point of 1 moves 1 USD per lot. Feed the calculator your account size, the percentage you are willing to lose and the distance to your stop, and it returns the size that puts exactly that much at risk — rounded down to your broker's lot step so the real risk never comes out above the target.
What makes SPX500 different
The S&P is the calmest of the American indices in point terms, which tempts traders into stops so tight that ordinary noise takes them out. Sizing it correctly usually means accepting a wider stop and a smaller lot, not the reverse. As with every index, confirm whether your broker uses a $1, $5 or $10 contract before trusting any figure.
Contract specification
| Symbol | SPX500 |
|---|---|
| Contract size (1 lot) | 1 |
| Quote currency | USD |
| Quoted decimals | 2 |
| Pip / point size | 1 |
| Pip value per standard lot | 1 USD |
SPX500 pip value by lot size
Values in USD, the currency SPX500 is quoted in. A point here is 1.
| Lot size | Units | Value of 1 point |
|---|---|---|
| Standard (1.00) | 1 | 1 USD |
| Mini (0.10) | 0.1 | 0.1 USD |
| Micro (0.01) | 0.01 | 0.01 USD |
A worked example
- Risk in money: a 10 000 USD account risking 1% puts 100 USD on the line.
- Stop distance in price: 100 points × 1 = 100.
- Loss per lot: 100 × 1 = 100 USD.
- Lot size: 100 ÷ 100 = 1, rounded down to 1.
The example assumes an account in USD. If yours is in another currency, every figure above gets multiplied by the rate from USD to your currency, which the calculator applies automatically.
Lot size for a 10 000 USD account
What each combination of risk and stop distance works out to. Read it as a sanity check on the number the calculator gives you.
| Risk | 50 points | 100 points | 200 points | 400 points |
|---|---|---|---|---|
| 0.5 % | 1 | 0.5 | 0.25 | 0.12 |
| 1 % | 2 | 1 | 0.5 | 0.25 |
| 2 % | 4 | 2 | 1 | 0.5 |
| 3 % | 6 | 3 | 1.5 | 0.75 |
Frequently asked questions
How much is one point worth on SPX500?
On a standard lot of 1 contract, one point of 1 is worth 1 USD. A mini lot is a tenth of that and a micro lot a hundredth. If your account is not in USD, multiply by the current rate from USD to your account currency.
What lot size should I use on SPX500?
There is no single right size: it depends on how much you are willing to lose and where your stop sits. Decide the loss first — most traders cap it at 1% to 2% of the account per trade — then divide that amount by the loss per lot at your stop distance. The calculator above does exactly that and rounds down to your broker's step.
Why does my broker show a different SPX500 lot size?
Almost always because the contract or the point definition differs. Open your platform's contract specification for SPX500, compare the contract size against 1 and the tick against 1, and correct them under "broker settings" above. The second cause is the conversion rate when your account currency is not USD; you can override that too.
What contract size does SPX500 use?
This page assumes 1 USD per point per lot, which is the most common setup, but it is not universal — $5, $10 and $25 contracts all exist. Check yours once in the contract specification and save it as a template; getting this wrong scales every size you calculate by the same factor.
Educational tool. Check the size in your platform before trading; leveraged trading carries a risk of loss.