How the AUDUSD lot size is calculated
Position size = risk in dollars ÷ (stop distance × value per unit). On AUDUSD, one pip is worth $10.00 per standard lot, so a 18 pips stop costs $180.00 per lot. $100 ÷ $180.00 = 0.55 lots (rounded down to the 0.01 step).
Spread and commission add a little to the real cost of each trade, so many traders round down further. Calculated at the current AUDUSD price of 0.69447.
The $10K rules in AUDUSD price moves
Rules are set in dollars, but you watch the AUDUSD chart. This is how far price can move against a 0.55-lot position before each limit is reached:
- Classic: target $1,000 (181.8 pips) + $500 (90.9 pips), daily loss $400 (72.7 pips), max loss $800 (145.5 pips), all with 0.55 lots.
- At 1% risk per trade it takes 4 losing trades in a single day to hit the Classic daily limit.
- 1-Step: target $1,000 (181.8 pips), daily loss $300 (54.5 pips), max loss $600 trailing (109.1 pips), all with 0.55 lots.
- At 1% risk per trade it takes 3 losing trades in a single day to hit the 1-Step daily limit.
- Ascent: target $500 (90.9 pips) + $500 (90.9 pips) + $500 (90.9 pips), daily loss $300 (54.5 pips), max loss $600 (109.1 pips), all with 0.55 lots.
- At 1% risk per trade it takes 3 losing trades in a single day to hit the Ascent daily limit.
- Spark: target $800 (145.5 pips), daily loss $200 (36.4 pips), max loss $400 (72.7 pips), all with 0.55 lots.
- At 1% risk per trade it takes 2 losing trades in a single day to hit the Spark daily limit.
Maximum AUDUSD position size on $10K
With 1:100 leverage one lot needs about $694 of margin, so a $10K account could open about 14.39 lots in total. That is a margin ceiling, not a target: the daily loss limit is the real constraint.
When AUDUSD moves most
Moves during the Sydney/Tokyo session and on Australian employment data, RBA decisions and Chinese data releases. Size down around those moments: wider swings mean a wider stop, and a wider stop with the same risk means fewer lots.