How the calculator works
The implied gap is the difference between where GIFT Nifty trades now and where the Nifty stood at the last close:
Implied gap = GIFT Nifty − premium − Nifty reference
Gap % = implied gap ÷ Nifty reference × 100
The verdict uses simple bands: under 0.15% either way reads as a flat opening, 0.15% to 0.5% as a mild gap, and above 0.5% as a strong gap. These bands are rules of thumb for a Nifty near 24,000, not exchange definitions.
Which Nifty number to use
- Nifty 50 futures close (best). GIFT Nifty is a futures price, so comparing it with domestic Nifty futures removes most of the premium automatically. Set the premium field to 0.
- Nifty 50 index close (common). This is the number on TV and in news. If you use it, enter yesterday's futures premium, roughly the gap between Nifty futures and the index at 3:30 PM, so the result is not inflated.
Why the premium matters is explained in GIFT Nifty vs Nifty 50.
How to read the result
| Implied gap | Typical reading |
|---|---|
| Within ±0.15% | Flat opening. Overnight news has had little effect. |
| +0.15% to +0.5% | Mild gap-up. Often driven by a positive US close or firm Asian markets. |
| Above +0.5% | Strong gap-up. Usually a clear global trigger, such as a sharp fall in crude oil or a positive policy surprise. |
| −0.15% to −0.5% | Mild gap-down. |
| Below −0.5% | Strong gap-down. Expect volatility in the first minutes. |
The actual open is set in NSE's pre-open session from 9:00 to 9:08 AM, so the gap can differ from the estimate, especially if news comes out between 8:30 and 9:00 AM.
Tips for better readings
- Use the GIFT Nifty level after 8:30 AM. Earlier readings miss Hong Kong's open at 7:00 AM IST and the latest news.
- Use the near-month contract. Far-month contracts carry a bigger premium.
- Near monthly expiry the premium shrinks to almost zero, so the index close becomes a fair reference.
- After a holiday in India while GIFT Nifty kept trading, the gap may reflect more than one day of news.
Frequently asked questions
How do I know if Nifty will open gap-up or gap-down today?
Compare GIFT Nifty after 8:30 AM with Nifty futures' last close. A difference above about +0.5% usually means a gap-up; below about −0.5% usually means a gap-down.
Why does the calculator show a gap-up when news says the market will open flat?
You probably compared GIFT Nifty with the Nifty 50 index without removing the futures premium. Enter the premium, or use Nifty futures as the reference.
Is this calculator a prediction?
No. It only shows what the current GIFT Nifty price implies. The open can be different, and the calculator is not investment advice.