What percent of my account is at risk if my 0DTE or short-dated options expire worthless?

How this is calculated

• Total premium at risk equals contracts multiplied by premium per share multiplied by 100 shares per standard contract.
• This assumes full loss of premium, which is what happens when a long option expires with no intrinsic value left. It doesn't apply the same way to spreads, credit strategies, or positions you plan to close before expiration.
• Same-day (0DTE) and other short-dated options are especially prone to expiring worthless from a small stock move, or no move at all, since there's little time left for the trade to work. A losing 0DTE trade usually means the full premium is gone, not a partial loss.
• There's no universal "safe" percentage. This tool flags common reference points: under 2% of an account on a single short-dated options trade is closer to how professional risk managers size speculative bets, 2% to 5% is elevated, and above 5% on a trade that can go to zero within hours is a concentration many traders regret after the fact.