Margin Calculator

How Margin Works in Indian F&O Markets

Margin is the money you deposit with your broker as collateral before entering a futures or options position. You are not paying the full contract value — you are putting up a fraction of it to control a much larger notional position. That leverage is what makes derivatives both powerful and dangerous.

In India, NSE computes margin requirements daily using the SPAN (Standard Portfolio Analysis of Risk) model — the same system used by CME in the US. SPAN calculates the worst-case loss your portfolio could suffer across 16 different market scenarios (different combinations of price and volatility moves). The highest loss across those 16 scenarios becomes your SPAN margin requirement.

On top of SPAN, your broker also collects Exposure Margin — an additional buffer typically set at 3% to 5% of the contract value for index futures and up to 5% for stock futures. SPAN protects against one-day moves; Exposure Margin is the cushion for residual risk SPAN might underestimate.

SEBI Peak Margin Rules — What Changed in 2021

Before May 2021, traders could trade in the morning and arrange margin by end of day. SEBI shut that window. The peak margin rule now requires you to maintain full margin at the highest intraday usage point — not just at end of day. Brokers check margin 4 random times per day and report the peak. Shortfall at any snapshot triggers a penalty.

Penalty for margin shortfall: 0.5% per day for the first 3 days, rising to 1% per day thereafter. For a ₹5 lakh shortfall held for a week, that's ₹17,500 in penalties — directly eating into trading capital.

The practical impact: intraday leverage dried up. Pre-2021, some discount brokers offered 20x leverage on intraday. Today, effective intraday leverage on Nifty futures is roughly 1.5x to 2x, depending on the broker's product offering. The free lunch of high leverage on zero margins ended.

Nifty and BankNifty Margin Reference

Lot sizes change periodically as SEBI keeps contract values between ₹5 lakh and ₹10 lakh. The figures below are illustrative based on typical margin requirements — always verify current figures on NSE's margin calculator or your broker's platform before trading.

Intraday vs. Overnight Margin — A Big Difference

Intraday positions (MIS/BO/CO orders on Zerodha, Groww, Upstox) attract the same full SEBI margin during market hours because of peak margin rules. What changes is that brokers square off your position before 3:20 PM so the risk does not carry overnight.

Overnight positions (NRML) must maintain full SPAN + Exposure margin through the night. Margins often increase before major events — RBI policy meetings, US Fed decisions, election results. NSE may hike margins by 25-50% in anticipation. If you hold overnight and wake up to a margin call, you have until the end of that trading day to top up, or the broker squares off.

One practical tip: keep at least 30% extra cash buffer above the required margin. Markets gap up or down — especially after 3 PM US trading — and you want that buffer to absorb a surprise without a forced exit at the worst possible price.

Options Margin — Buyer vs. Seller Asymmetry

Options buyers pay only the premium upfront. If you buy 1 lot of Nifty 24000 CE at ₹100, you pay ₹100 × 75 = ₹7,500. That is your maximum loss. No additional margin is needed because your risk is fully defined.

Options sellers face full margin requirements because their theoretical loss is unlimited (for naked calls) or large (for puts). Selling 1 lot of the same Nifty CE requires roughly ₹1.2-1.5 lakh in margin. Selling spreads reduces this — a 24000/24100 bull call spread needs far less margin than a naked 24000 CE sale because the 24100 CE purchase caps your upside loss.

This margin asymmetry is why most retail traders gravitate toward buying options. The defined-risk structure of buying requires far less capital. The flip side: option buyers need to be right on direction AND timing AND magnitude of move. Sellers collect premium with time on their side but require significantly more capital.