Contracts from a dollar stop
The formula rounds down. Risk $200 with a 10-tick stop on MES: one tick is $1.25, so one contract risks $12.50, and 200 divided by 12.50 is 16 contracts. The same 10 ticks on ES are $125 a contract, so the same $200 is one contract. That gap is the reason a stock position-size calculator is the wrong page.
Fees are not in the stop. A round turn on a prop schedule can be a few dollars a contract. If the stop is tight, subtract the fee from the risk before you divide, or the fill will lose more than the number on this page. The fee calculator names the dated schedule it used.
This does not know the prop firm’s remaining drawdown. Size the trade here, then compare the dollar risk with the room on the firm’s dashboard. Topstep’s Maximum Loss Limit and Apex’s intraday threshold are different rooms. The firm page is the quote. The dashboard is official.
A second pass with fees: the 16 MES contracts from the $200 example each carry a round turn. If the dated schedule is about $1.50 a round turn, sixteen contracts are about $24 of fees on top of the $200 stop. The stop itself is still $200 of price risk. The account loses the fee as well if the stop fills. Subtract that fee from the dollars you are willing to lose, then divide again, if the fee is large next to the stop. The fee calculator names the schedule. This page will not subtract it for you, because the schedule depends on the firm and the platform.