Position sizing inside a drawdown framework

In a funded or challenge account, the maximum drawdown is not a suggestion — it is a wall. Hit it and the account is gone, regardless of how good your edge is. That changes the entire sizing question: you are no longer optimizing for the best trade, you are optimizing for survival across a sequence of trades.

Start from the floor and work backwards. If your hard limit is 10% and you want to survive a realistic losing streak, decide how many consecutive losses your sizing must absorb before you are near the wall. Risking 1% per trade lets you take roughly ten losers in a row before the floor; risking 3% gives you barely three. The smaller number buys you room to be wrong, which you will be.

Scale risk to distance from the floor, not to confidence. When you are fresh and far from the limit, a normal unit of risk is fine. As your equity drifts toward the drawdown line, cut size — half-risk, then quarter-risk. This is counter-intuitive because it slows your recovery, but it is exactly what stops a bad week from becoming a blown account.

Never average down into a loser to 'fix' a drawdown. Adding size to a losing position is how a 5% drawdown becomes a 10% one in a single afternoon. If the trade is wrong, the position is wrong; take the loss at your planned level and reset.

The traders who last are not the ones with the highest win rate — they are the ones who never let a single trade, or a single day, threaten the whole account. Size for the streak you hope never comes, and you will still be trading when it does.