SPAN Margin Calculator

NRML (Normal) is the product type for overnight positions — the broker blocks the full SPAN + Exposure margin as published by the exchange, and you can carry the trade past the closing bell. MIS (Margin Intraday Square-off) is intraday-only — brokers offer additional leverage (typically 3-5×, sometimes higher) by reducing the margin requirement, but the position is auto-squared-off by ~3:15 PM (~11:30 PM for currency / commodity). MIS uses less capital but gives no overnight protection — if the exchange raises SPAN intraday or the position moves against you, the broker can square off without warning. Many traders use MIS to reduce capital lock-up on day trades and switch to NRML only when they intend to hold.

For option buyers (long calls / long puts), your maximum loss is the premium you pay — there is no obligation beyond that, so SPAN margin equals the full premium. A 1-lot Nifty call at ₹150 premium needs only ₹150 × 75 = ₹11,250 (plus a tiny 1% exposure buffer the broker may add). Option sellers (writers) are a different story — they face theoretically unlimited risk if the underlying moves against them, so SPAN charges roughly 13% of the underlying value, reduced by the premium received. Selling a Nifty call without owning the underlying can therefore block ₹2 Lakh+ per lot.

SPAN is volatility-driven — calmer underlyings need less margin. The exchange measures the price-scan range from each contract's historical volatility, then applies the 16-scenario risk array. Low-beta names like HDFC Bank or large-cap PSUs may carry SPAN as low as 10-11%, while high-volatility mid-caps or recently listed F&O stocks can carry 18-20%+. Indices (Nifty / BankNifty) sit around 12-13% on average. Currency futures (USDINR) are famously the cheapest at ~1.5% SPAN because RBI manages the daily range tightly. Commodity futures (Crude, Silver) sit at the high end (8-10%) because of overnight gap risk from international markets.

If the exchange raises SPAN intraday (volatility spike, large overnight gap) or the position moves against you, your account margin can drop below the SPAN + Exposure requirement — this is called a margin shortfall. Brokers typically issue a margin call by SMS/email and give you a window (often a few hours, or until end of day) to add funds. If you don't, the broker will square off positions — usually the most loss-making ones first — to bring the account back above requirement. SEBI's peak margin rules also penalise shortfalls: a fixed percentage penalty (0.5% to 5%) is levied for shortfalls on more than 3 occurrences in a month or shortfalls > ₹1 Lakh. Always keep a buffer of 15-20% above the SPAN requirement.