Position size calculator
Computes the trade size from your deposit in two modes — fixed percentage and fixed amount — and shows what happens to the account after a run of losses.
Trade size
$20.00
That is 2.00% of the deposit
After 5 losses
$903.92
Drawdown 9.6%
Losses to lose half
35
In a row, without a single win
Trade after the streak
$18.08
The percentage lowered the size on its own
What a run of losses does
| Loss | Trade size | Deposit left | Risk share |
|---|---|---|---|
| 1 | $20.00 | $980.00 | 2.00% |
| 2 | $19.60 | $960.40 | 2.00% |
| 3 | $19.21 | $941.19 | 2.00% |
| 4 | $18.82 | $922.37 | 2.00% |
| 5 | $18.45 | $903.92 | 2.00% |
A fixed percentage brakes you on a drawdown and accelerates you on growth by itself — the size never needs recalculating by hand.
Why position size is worth calculating
Trade size is the only risk parameter entirely in your hands. The payout is set by the platform and the outcome of any single trade cannot be predicted, but exactly how much you lose on a loss is your own decision, made before you enter.
In binary options the calculation is simpler than on other markets: a loss takes the whole trade amount, so the risk equals the size. No stop-losses, no counting pips — just a percentage of the deposit.
Trade size = deposit × risk percentage
Two modes, and why they are not the same thing
Fixed percentage. The trade is computed from the current deposit. The deposit grows — the trade grows; it dips — the trade shrinks. The share of risk stays constant automatically.
Fixed amount. The trade is set in money and does not move. Easy to execute, but in a drawdown its share of the deposit rises.
The difference shows up over a run of losses. A $1,000 deposit, 2% risk against a fixed $20:
| After losses | Fixed percentage | Fixed amount |
|---|---|---|
| 5 in a row | trade $18.08, share 2% | trade $20, share 2.2% |
| 10 in a row | trade $16.34, share 2% | trade $20, share 2.5% |
| 20 in a row | trade $13.35, share 2% | trade $20, share 3.3% |
A fixed percentage puts the brakes on for you in a drawdown. A fixed amount asks you to do it by hand — and a drawdown is precisely where discipline is thinnest.
How many losses in a row the account survives
The key figure the calculator gives: how many consecutive losses cut the deposit in half.
| Risk per trade | Losses to lose half |
|---|---|
| 1% | 69 |
| 2% | 35 |
| 3% | 23 |
| 5% | 14 |
| 10% | 7 |
The gap between 1% and 5% reads like "five times the risk", but in practice it is the difference between 69 and 14 losses in a row — that is, between a statistically impossible event and a perfectly ordinary bad week.
Where people go wrong
- Raising the size to recover faster. That doubles the speed of travel in whichever direction the account is already going.
- Taking the percentage from the starting deposit instead of the current one. Percentage mode then turns into a fixed amount, with all its drawbacks.
- Sizing "by feel" on a confident signal. Confidence does not change your win rate, while a bigger size does change the size of the loss.
FAQ
What percentage of the deposit should go into one trade?
1% for a beginner, up to 2% with experience. Above 2% is no longer money management: at a 5% risk a run of five losses takes about a quarter of the account, and ten losses take almost half. The percentage is fixed before the session and does not change along the way.
Which is better — a fixed percentage or a fixed amount?
The percentage, unless you recalculate the amount by hand. It shrinks the trade in a drawdown and grows it on the way up on its own, so the share of risk stays constant. A fixed amount does none of that: as the deposit falls its share rises, and risk quietly increases exactly when it should be coming down.
Why does the calculator model a run of losses rather than a single trade?
Because one trade decides nothing while a run decides everything. The difference between 1% and 3% risk looks trivial on a single trade, but after ten losses in a row it is the difference between a 10% and a 26% drawdown — and climbing out of the second takes several times longer.
Does the calculation account for the asset's payout?
No, and that is deliberate. Position size answers the question “how much do I lose if the trade is a loss”, and in binary options a loss always takes the whole amount regardless of the payout. The payout matters for the breakeven threshold — a separate calculation.
Do you need to recalculate the amount after every trade?
In percentage mode — yes, by definition: the trade is always computed from the current deposit. In practice it is enough to recalculate after every noticeable move in the account, say every 10%. In fixed-amount mode the recalculation is manual and mandatory, otherwise the share of risk drifts.