What it is — Position Sizing
Position sizing is choosing how many lots to trade so that hitting your stop loses a predetermined amount — typically 1% of the account. It connects three numbers: account risk budget, stop distance in pips, and pip value per lot.
The formula: lots = risk $ ÷ (stop pips × pip value per lot). Risk $100, stop 25 pips, pip value $10/lot → 100 ÷ 250 = 0.4 lots. Same $100 with a 100-pip stop → 0.1 lots. The risk stays constant; only the size breathes.
Why it matters — Position Sizing
- It is the whole game. Entries and indicators decide when; sizing decides whether you survive to be right.
- It normalizes every trade to equal risk, so your results measure skill, not luck of stop distances.
- It kills the account-killer: oversizing after losses (“win it back” sizing) is how small edges die.
The formula, on a real account
Balance $1,000, risk 1% = $10. Stop distance 25 pips. Pip value on EURUSD: $10 per standard lot. Lot size = $10 ÷ (25 × $10) = 0.04 lots. That is the whole method: (Balance × Risk %) ÷ (Stop pips × Pip value). Change any input and the size follows: a $2,500 account with a 15-pip stop at the same 1% gives $25 ÷ (15 × $10) = 0.16 lots. Notice what is not in the formula: leverage, gut feeling, and how sure you are. The Position Size Calculator exists so you never do this arithmetic with money on the line.
Size follows the stop, not the confidence
Same $10 risk budget, three stops: a 10-pip scalp stop sizes to 0.10 lots; the 25-pip chart stop sizes to 0.04; a wide 50-pip swing stop sizes to 0.02. Tighter stops always produce bigger sizes — which is exactly why “just tighten the stop” is not free: tight stops in noise get hit more often. The professional loop runs one direction: read the chart for the invalidation level, measure the honest pip distance, let the formula produce the size. Confidence is not an input anywhere in that chain — and that is the point.
Frequently asked questions — Position Sizing
Is 1% per trade really enough to grow?
Yes — compounding math: risking 1% to make 2% (1:2), a 40%-win system adds ~0.2R per trade ≈ meaningful monthly growth at hundreds of trades a year. Survival first, speed later.
What lot size should I trade with a $100 account?
At 1% risk that is $1: a 10-pip stop on EURUSD sizes to 0.01 lots — one micro lot. Honest answer: at $100, most meaningful stop distances price you out of real-money trading, which is what demo accounts are for.
Does position size change when leverage changes?
No. Pip value depends on lot size and pair; leverage only changes the margin locked. Your 0.04-lot position risks the same per pip at 1:30 or 1:500.
What if my broker’s lot size makes the risk 1.3%?
Round down. Micro lots (0.01) exist precisely for fine-grained sizing — being under budget by a little is fine; over is not.
Related terms — Position Sizing
Related tools — Position Sizing
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