Risk sizing

Most order forms ask how big a position you want. That is the wrong question. What a trader actually decides is how much they are willing to lose if the trade is wrong.

taker lets you say that directly:

long eth, risk $200, stop at 1800

What that does

taker computes the size such that being stopped out costs approximately $200 — not that the position is $200.

With ETH near 1900 and a stop at 1800, the distance is $100 per ETH. Risking $200 over a $100 move means a position of 2 ETH — roughly $3,800 notional, which at 5× uses about $760 of margin.

You say	taker computes
risk $200, stop 1800, price 1900	2 ETH ≈ $3,800 notional
risk $200, stop 1850, price 1900	4 ETH ≈ $7,600 notional
risk $200, stop 1700, price 1900	1 ETH ≈ $1,900 notional

Notice the pattern: a tighter stop buys a larger position for the same risk. That relationship is the whole point, and it is invisible in an interface that only asks for size.

Why this is the feature to learn

It inverts the decision into the one you can actually reason about. “How much do I lose if I’m wrong” is answerable. “How many ETH should I buy” depends on a calculation most people do in their head, badly, under time pressure.

Using it

In chat, name a risk amount and a stop:

short btc, risk $100, stop at 66000

On the trade page, set the size unit to Risk $ and enter the stop price in the field that appears.

The honest caveats

• Risk is an estimate, not a guarantee. A stop becomes a market order when it triggers, so a gapping market can cost more than the number you named. See Order types.
• Fees and funding are on top. The calculation covers price movement to your stop; the round-trip fee and any funding paid are additional.
• The stop has to make sense. A stop above the entry on a long is refused — that is not a stop, and taker will say so rather than sizing something absurd.
• Your risk limits still apply. A tight stop can imply a position larger than your max order size, in which case the order is refused and taker tells you what would fit.