SENSEX options, 1-minute replay
SENSEX option simulator: replay any minute since August 2023
Replay a real SENSEX options day, minute by minute. Choose a past session, trade from the chain as it stood, step the clock and watch the P&L, payoff and Greeks move. SENSEX data starts on 7 August 2023, in 1-minute steps, with a 35-day lag; SEBI requires 30. The tool below opens on SENSEX, and the preset days work without an account.
SENSEX is a BSE index, and our SENSEX replay is built on approximations that the NSE indices do not need. We say what they are further down, before you rely on any number. Everything else here is specific to SENSEX: two expiry-day changes in under two years, the lot size history, and the cost of a straddle. For the NSE indices see NIFTY and Bank Nifty, or the hub.
Calm day: 0.31% high-low range, India VIX 12.6.
Option chain
| Calls | Strike | Puts | ||||||
|---|---|---|---|---|---|---|---|---|
| OI · chg | IV | LTP · Δ | Buy or sell call | Strike | Buy or sell put | LTP · Δ | IV | OI · chg |
| Pick a date and time to load the chain. | ||||||||
| Leg | Entry | LTP | P&L | Status | Actions |
|---|---|---|---|---|---|
| No position yet. Click B or S on any strike in the chain. | |||||
| Greek | Position | Means |
|---|---|---|
| No position yet. | ||
- Nothing yet. Every entry and exit is written here with its minute.
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You've been trading this setup by hand. Tell us the logic, and Cookie will turn it into an algo you can backtest and review before anything goes live.
Historical replay for education and analysis. Past prices; not investment advice. Nothing here places orders.
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What is approximated in the SENSEX data
We want to be plain about this. For SENSEX, our data has no BSE settlement price file and no BSE margin file, the lot size history is written by hand from BSE circulars because there is no BSE bhavcopy to check it against, and the option chain is thinner than NIFTY's. Prices themselves are still traded prices, never modelled, and a strike that did not trade in a minute shows its last price, greyed.
Thinness is measurable. Between 09:15 and 09:20 on 3 June 2024, 50 SENSEX contracts traded, against 431 for NIFTY on the same morning, so the SENSEX preset for that day opens at 09:20. On 27 of 767 trading days there was no usable at-the-money straddle price at 09:20 in either of the two nearest expiries. For NIFTY it was 7 of 1,652. In practice:
- Use SENSEX to learn how a trade behaves through a day.
- Expect more greyed prices than on NIFTY, especially at the open and away from the money.
- Do not read a single SENSEX price, margin or settlement figure as exact.
How the SENSEX chain works in the replay
SENSEX strikes are 100 points apart. The chain shows 15 strikes either side of the at-the-money strike, so 1,500 points each way, with Delta, IV, OI and OI change beside each price. The expiry tabs list the contracts that traded on the date you chose.
Your first SENSEX trade, in two clicks
Pick a preset day from the chips under the date bar. In the chain, click B on the call and B on the put at the middle row, the at-the-money strike, to buy a straddle, or S on both to sell one. Each click adds one lot at that minute's price. If a strike has no price at all, the button asks for the price to use rather than inventing one. Then move the clock and watch the position panel.
Without an account you can place trades and move the clock once. To keep going you sign up free, and your trades come with you.
SENSEX lot size history
In our table the SENSEX lot is 10 for contracts expiring up to 3 January 2025, and 20 for expiries after that date. The change follows BSE's circular of late November 2024, and the weeks around it, when old and new contracts traded together, are not modelled. Check any figure you plan to rely on against the exchange.
SENSEX expiry history: Friday, Tuesday, Thursday
The first SENSEX weekly expiry in our data is Friday 11 August 2023, and Friday remained the weekly day until 3 January 2025. From 7 January 2025 it was Tuesday, and the last Tuesday expiry is 26 August 2025. The first Thursday expiry is 4 September 2025, and Thursday has been the day since. The 31 January 2025 monthly still expired on a Friday; monthlies were on Tuesday from February 2025 and on Thursday from September 2025. When the usual day is a holiday the expiry moves to an earlier day: Thursday 25 January 2024 is one example, because 26 January has no trading in our data.
Two weekday changes in under two years make SENSEX a useful index for one exercise. Replay the same stage of the weekly cycle under each expiry day, for example the day before expiry, and compare the straddle prices below.
What a SENSEX at-the-money straddle cost, from our data
For each trading day from 7 August 2023 to 11 September 2026 (740 of 767 days had usable prices), we took the close of the 09:19 minute, the at-the-money strike, and the call and put of the nearest expiry at least a day away. Implied volatility is solved from both legs with Black-76 on the forward the pair implies. Medians are shown, with the 10th to 90th percentile range in brackets.
- Implied volatility at 09:20, all days: 14.5% (10.4% to 21.7%)
- By year: 2023 from August 12.9%, 2024 16.0%, 2025 12.7%, 2026 so far 15.6%
- Straddle price, Friday era to 3 January 2025: 835 points, 1.12% of the index (0.73% to 1.65%)
- Tuesday era, 7 January to 26 August 2025: 984 points (1.25%)
- Thursday era from 4 September 2025: 855 points (1.07%); one day before expiry 589 points (0.73%); four to seven days out 1,049 points (1.28%)
Multiply points by the lot to get rupees: for straddles four to seven days from expiry since September 2025, about 21,000 rupees per lot at 20. The price is the premium of both legs together. Because of the thin chain described above, read single-day prices as indicative.
Three SENSEX days to replay
7 July 2025: a calm session
SENSEX opened -0.04% and closed +0.01% inside a 0.31% range, with India VIX at 12.6. At 09:20 the 83,400 straddle for the next day's Tuesday expiry was priced at 552.2 points, 0.66% of the index, at an implied volatility of 14.1%. A quiet day to learn the chain on. Open 7 July 2025 at 09:20.
22 November 2024: a Friday expiry day
The weekly contract expired that afternoon. SENSEX opened +0.25%, ranged 2.58% and closed +2.54%. At 09:20 the 77,400 straddle of that day's own contract was priced at 513.2 points (0.66%), and the same strike a week out was priced at 1,292.3 (1.67%). Open 22 November 2024 at 09:20.
7 April 2025: a volatility spike
SENSEX gapped down 5.19% and India VIX rose 66.1% on the day. The index recovered 2.36% from the open and closed 2.95% below the previous close. By 09:20 the 72,200 straddle for the 8 April expiry was priced at 1,824.4 points, 2.53% of the index, an implied volatility above 50%. Start at 09:15 to trade the open. Open 7 April 2025 at 09:15.
After the replay
Once a SENSEX idea works by hand, give Cookie the rules: entry time, strikes as distance from the at-the-money strike, and the exit. Cookie writes the algo, you backtest it, and deploy with your broker when ready. Algo trading carries risk, and a backtest describes the past. The manual replay to algo guide shows the steps. The historical option chain guide explains how the chain you just used is built.
Questions traders ask
Is SENSEX option data in the simulator exact?
Prices are traded prices and are never modelled. But SENSEX is a BSE index, and our data has no BSE settlement or margin file, a hand-written lot history, and a thinner chain than NIFTY. Use it to learn how a trade behaves.
Which day does the SENSEX weekly expire in the replay?
Friday from 11 August 2023 to 3 January 2025, Tuesday from 7 January 2025 to 26 August 2025, and Thursday from 4 September 2025. Holidays move an expiry to an earlier day.
How far back does the SENSEX data go?
To 7 August 2023, in 1-minute steps. The most recent replayable day is 35 days old; SEBI requires 30. The preset days work without an account, and a free Tradetron login opens every trading day.
What is the SENSEX lot size in the simulator?
10 for contracts expiring up to 3 January 2025, and 20 after that. The table is written by hand from BSE circulars, so check it against the exchange before relying on it.
Why do some SENSEX strikes show greyed prices?
The SENSEX chain is thinner than NIFTY's. When a strike did not trade in a minute, you see its last traded price, greyed, never a model price. It happens more often further from the money and at the open.
Can I compare SENSEX with NIFTY in the same replay?
Yes. The NIFTY simulator uses the same tool. Replay 7 April 2025 on both indices and compare how the two chains behave at the open.
Keep reading
- Free NIFTY & Bank Nifty option simulator: replay a real day
- NIFTY option simulator
- Bank Nifty option simulator
- Historical option chain data, explained
- How to practise options trading with replay
- The option payoff graph, explained
- From manual replay to algo
Historical replay for education and analysis. Past prices; not investment advice. Nothing here places orders. Algo trading carries risk.