How is the Sensex calculated?

Sensex is calculated by summing the free-float market caps of its 30 constituents, dividing by an index divisor, and multiplying by 100. The index divisor is adjusted for corporate actions and constituent changes to maintain continuity. The methodology is the same free-float market cap weighting used by most global equity benchmarks.

What is the difference between Sensex and Nifty 50?

Sensex tracks 30 stocks on BSE; Nifty 50 tracks 50 stocks on NSE. Both use free-float market cap methodology and are reviewed semi-annually. Sensex was established in 1986 with a base of 100; Nifty 50 in 1996 with a base of 1,000. Both are highly correlated and serve as India's primary large-cap equity benchmarks.

What is Nifty Next 50?

Nifty Next 50 (also called Nifty Junior) tracks the 50 companies ranked 51–100 by market cap on NSE — the tier immediately below the Nifty 50 constituents. These companies are large-cap stocks and candidates for future Nifty 50 inclusion. The index shows higher return volatility than Nifty 50 but has historically delivered stronger long-term performance.

Sensex Index: Composition, Calculation & Nifty 50 Comparison

Q: What is the Sensex index?

Sensex is BSE's flagship equity index, tracking 30 large-cap stocks listed on the Bombay Stock Exchange. Established in 1986 with a base year of 1978-79 and base value of 100, it uses free-float market capitalisation methodology. The composition is reviewed semi-annually by the S&P BSE Index Committee.

Sensex Index: What It Is, How It Is Calculated and How It Compares to Nifty 50

Team Sahi

Published: 4 Mar 2026, 05:30 AM IST (15 hours ago)

Last Updated: 4 Mar 2026, 05:38 PM IST (3 hours ago)

5 min read

The Sensex index is India's oldest equity benchmark, tracking 30 large-cap stocks listed on the Bombay Stock Exchange (BSE). It is one of two primary indicators of Indian stock market direction — the other being NSE's Nifty 50.

What Is the Sensex Index?

Sensex is short for Sensitive Index. It was created by BSE in 1986 and uses 1978-79 as its base year, with a base value of 100. As of 2025, Sensex has crossed 80,000 — reflecting four decades of Indian equity market growth from the base of 100.

The Sensex is a free-float market capitalisation-weighted index. Each stock's weight is based on the portion of its total shares available for public trading — not the total issued share capital. This methodology is standard across major global indices.

How Is Sensex Calculated?

The Sensex calculation follows a four-step process:

For each of the 30 constituent stocks, calculate the free-float market cap (current price × free-float shares outstanding)
Sum the free-float market caps of all 30 stocks
Divide by the index divisor — a fixed number maintained by BSE
Multiply by 100 to express the result relative to the base year value

The index divisor is adjusted whenever there are corporate actions (bonus issues, stock splits, rights issues) or constituent changes. This adjustment ensures continuity — the index level does not jump artificially when a company is added or removed.

Sensex Index Composition

The 30 Sensex constituents are selected by the S&P BSE Index Committee using these criteria:

Listed on BSE for at least 12 months
Among the largest companies by free-float market capitalisation
High trading frequency and liquidity
Positive earnings track record
Sector representation across the Indian economy

The composition is reviewed semi-annually. Sectors represented include financials, information technology, FMCG, energy, metals, pharmaceuticals, telecommunications, and consumer goods.

Sensex vs Nifty 50: Key Differences

Aspect	Sensex	Nifty 50
Exchange	BSE	NSE
Number of stocks	30	50
Base year	1978-79 (base value: 100)	1995-96 (base value: 1,000)
Methodology	Free-float market cap weighted	Free-float market cap weighted
Review frequency	Semi-annual	Semi-annual
Administrator	S&P BSE Indices	NSE Indices Ltd

Both Sensex and Nifty 50 track large-cap Indian equities and are highly correlated. The Nifty 50 covers a broader set of companies. For most purposes, the two move together — divergences are typically small and short-lived.

What Is the Bank Nifty Index?

The Bank Nifty index — officially Nifty Bank — is a sectoral index on NSE tracking 12 large and liquid Indian banking stocks. Unlike Sensex and Nifty 50, which are diversified across sectors, Bank Nifty is concentrated entirely in banking.

Bank Nifty is India's most actively traded derivative index by volume. It is used to take directional or hedging positions on the banking sector specifically. Bank Nifty can diverge significantly from Nifty 50 when banking-specific catalysts drive sentiment — RBI rate decisions, credit growth data, or major bank earnings results.

Nifty Next 50 and Nifty Midcap 100

Beyond large-cap benchmarks, NSE maintains indices for other market-cap segments:

Nifty Next 50: Also called Nifty Junior. Tracks the 50 companies ranked 51–100 by market cap on NSE — immediately below the Nifty 50 constituents. These are large-cap companies that are candidates for eventual Nifty 50 inclusion.
Nifty Midcap 100: Tracks 100 midcap companies listed on NSE, typically ranked between 101 and 250 by full market capitalisation. This index captures growth segments of the Indian economy not yet in large-cap benchmarks.

Nifty Next 50 and Nifty Midcap 100 have historically shown higher return volatility than Nifty 50 but have delivered stronger long-term returns during extended bull cycles. Both are used as benchmarks for midcap and small-cap fund performance.

How to Track Sensex Live

Sensex today live data is available on:

BSE India website (bseindia.com) — official source for real-time Sensex levels
NSE India website (nseindia.com)
Indian broker trading terminals
Financial news platforms and data aggregators

Sensex trades during market hours from 9:15 AM to 3:30 PM IST on trading days. A pre-market session runs from 9:00 AM to 9:08 AM IST, during which opening levels are determined. After-hours Sensex data reflects the closing price until the next trading session opens.