Calculator
Margin calculator
What a position actually blocks: SPAN worst-case move plus the exposure add-on, across up to two legs.
Estimate only. NSE publishes the SPAN risk array every morning; a short option also carries an ELM + MTM add-on on top.
₹5,88,000
margin blocked · 10× effective leverage
Hover a segment for value + share.
- Future₹4,41,000SPAN + 15% exposure. Exchange file changes daily.
- Equity₹1,47,0005.0% block — VaR + ELM + MTM. Intraday MIS is 20% (5x).
- Position value₹58,80,000
- Against ₹5,00,000 available117.6% used
Broker blocks are usually higher than the exchange minimum — check your broker's contract note for the figure that actually applies.
What this calculator answers
Margin is blocked on two separate things: a SPAN worst-case move for the day, and an exposure add-on. A long option blocks only the premium you paid; a short option blocks the larger of the worst plausible one-day loss and 12.5% of its strike value. Enter up to two legs to see the total block and the leverage it actually buys.
How it is calculated
Each leg contributes a SPAN estimate — for futures and short options the adverse one-sigma move in price (and, for options, in volatility), for a long option the premium itself — and then the block is the larger of that SPAN figure and the exposure floor. Equity legs use VaR + ELM + MTM as a flat percentage of position value (5% for a delivery block, 20% for intraday MIS). Legs are summed; effective leverage is position value ÷ total block.
This reproduces the method SPAN uses, not the exchange file itself — NSE republishes the risk array every morning, so only the broker's contract note carries the exact number. Broker blocks are usually higher than the exchange minimum, and ELM + MTM can be added on top.
Common questions
Is this the exact margin my broker will block?
No. SPAN is an exchange-published risk array that changes every morning and differs by strike and expiry. This shows the method and the order of magnitude so you can sanity-check a broker's figure — the contract note is the authority.
Why does a long option block less than a short one?
You have already paid the full premium, so there is nothing left to finance. On the short side the exchange has to cover what you owe if the move goes against you, which is why the strike-based exposure floor usually dominates.
What is exposure margin on top of SPAN?
An extra buffer the exchange adds beyond the modelled worst case — on short options it is expressed as a percentage of strike value. It exists so a gap or a volatility spike does not immediately trigger a margin call.
Source & freshness
- Source
- Deterministic formula in lib/calculators.ts
- Timeliness
- Static-verified
- Method
- calculated
- Note
- Illustrative projection from your inputs — not a market quote.