The number one reason accounts get wiped is not bad analysis — it is the wrong trade size. A trader with average analysis and disciplined sizing survives for years. A trader with excellent analysis and random sizing blows up in a month. Here is the exact formula.
Do it instantly: lot size calculator for gold and forex — enter your balance, risk % and stop loss to get the right lot.
The rule before the formula
Set a fixed percentage of your balance that you risk on a single trade. The common range among professionals: 1% to 2%. With a $1000 balance, that means the maximum loss on one trade is between $10 and $20.
Why a fixed percentage and not a fixed amount? Because it shrinks when you lose (protecting you from a spiral) and grows when you win.
The formula
Example 1 — EURUSD
- Balance: $1000
- Risk: 1% → $10
- Stop loss: 25 pips
- Pip value for a full lot on EURUSD: $10
The calculation: 10 ÷ (25 × 10) = 10 ÷ 250 = 0.04 lots
So you open the trade at 0.04. If the stop is hit, you lose exactly $10 — not a dollar more.
Example 2 — same balance, wider stop
- Same balance and the same 1% ($10)
- Stop loss: 60 pips instead of 25
The calculation: 10 ÷ (60 × 10) = 0.016 lots → round it to 0.01
The lesson: the wider the stop, the smaller the size must be. The two are linked — you cannot increase both at once.
Pip value — how to find it precisely
Pip value varies by pair and by broker, especially on gold and indices. Do not rely on numbers from the internet — read it from your platform:
- In MetaTrader 5, open the Market Watch window (Ctrl+M).
- Right-click the symbol → Specification.
- Look at Contract Size, Tick Value and Digits.
The easiest practical check: open a 0.01 trade on a demo account and watch how much the profit changes with each pip of movement. Multiply by 100 and you have the value for a full lot.
Mistakes that cost money
"I put the stop far away so it doesn't get hit"
A far stop is not protection — it is a postponed bigger loss. The right move is to reduce the size to match the far stop, not to increase the risk.
"This trade is a sure thing, I'll size up"
There is no sure trade. Most account wipeouts happen on a trade its owner was "certain" about.
Doubling the size after a loss
That is martingale in its manual form, and its ending is known mathematically. We explain it in detail in the types of robots guide.
Forgetting that leverage is not the risk
Leverage sets the maximum size you can open, not the size you should open. 1:500 leverage does not mean you open bigger — it means the broker allows you to, and that is your responsibility.
Quick table — $1000 balance, 1% risk
| Stop loss | Lot size (pair with $10 pip value) | Loss if hit |
|---|---|---|
| 10 pips | 0.10 | $10 |
| 20 pips | 0.05 | $10 |
| 50 pips | 0.02 | $10 |
| 100 pips | 0.01 | $10 |
Notice: the loss is the same in every case. That is the whole idea.
Sizing decides how much you lose; it does not decide whether you win. It keeps you in the game long enough to learn — it is not a substitute for a strategy.