What Is Cost Inflation Index (CII) and How It Impacts Your Capital Gains Tax in India

Written by Jainam Resources

Last Updated on: November 19, 2025

Introduction

Back in 2005, you might have bought a cozy flat for ₹40 lakh — a big step, a proud moment. Fast-forward twenty years: property prices have soared, and inflation has quietly eroded the value of money. Now, as you prepare to sell, the price looks like a fortune on paper. But the moment you start calculating capital gains, you realize the taxman doesn’t see inflation — only numbers.

That’s where the Cost Inflation Index (CII) steps in. It’s a tool the Central Board of Direct Taxes (CBDT) updates every year to ensure that inflation doesn’t inflate your tax bill. In this blog, we’ll explore what is cost inflation index, how it works, and why it’s crucial for calculating your capital gains tax in India — explained through stories, data, and real-life logic.

What Is the Cost Inflation Index (CII)?

The Cost Inflation Index (CII) is a tool used to calculate long-term capital gains when you sell or transfer a capital asset. Capital assets include things like land, buildings, stocks, trademarks, patents, and other valuable properties.

In most cases, long-term assets are recorded in the books at their original purchase price. Since these values are not updated over time, the rising market prices are not reflected. So, when you finally sell the asset years later, the selling price looks much higher compared to the old purchase price — which results in higher taxable gains.

To correct this mismatch, the government uses the Cost Inflation Index. CII adjusts the original purchase price for inflation. Once the cost is inflation-adjusted, the taxable gain reduces, and the tax liability becomes more realistic and fair.

Important Points to Remember

• If you inherit a property through a will, you must use the CII of the year in which the previous owner purchased the asset.
• Any cost of improvement done before 1st April 2001 has to be ignored.
• Indexation is not allowed on bonds or debentures, except for:
  • Capital indexation bonds
  • Sovereign Gold Bonds (SGBs) issued by RBI
• From 1st April 2023, indexation benefits are not available for Debt Mutual Funds.
• From 23rd July 2024, indexation benefits are discontinued for all assets.
  • However, for land and buildings bought before 23rd July 2024, you can choose between:
    • 12.5% tax rate without indexation, or
    • 20% tax rate with indexation
  • For land or buildings purchased on or after 23rd July 2024, the tax rate will be 12.5% without indexation for long-term assets.

For FY 2025–26, the CII stands at 376, as per CBDT Notification No. 70/2025 dated 1st July, 2025

A Cost Inflation Index table is used to determine the indexed cost of acquisition or improvement when computing long-term capital gains on the sale or transfer of capital assets such as land, buildings, shares, and other investments.

What Is the Purpose of CII?

Taxes are meant to be fair — and fairness demands context. The purpose of the cost inflation index is exactly that: to prevent taxpayers from being penalized by inflation. Without CII, an investor who bought an asset 20 years ago would pay tax on an artificially inflated gain, even if the “profit” was just the result of money losing value over time.

The CII neutralizes this distortion by adjusting the purchase cost according to inflation. This ensures that your long-term capital gains are taxed only on real appreciation. The annual increase in the index, such as the jump from 363 (FY 2024–25) to 376 (FY 2025–26), directly reflects the government’s attempt to keep taxation aligned with rising price levels.

What Does a Base Year in CII Mean?

When you hear “cost inflation index base year India,” it refers to the starting point for all index calculations. Earlier, the base year was 1981–82, but valuing old assets based on that year was difficult and often unrealistic.

To simplify, the government shifted the base year to 2001–02, assigning it a value of 100. This change took effect from FY 2017–18.

If you bought an asset before 2001–02, you can use the higher of its actual cost or fair market value (FMV) as on 1 April 2001 and then apply indexation from that year onward.

This change, known as the cost inflation index change of base year in India, made long-term capital gains calculation fairer and more practical.

How Is Indexation Applied for Long-Term Capital Assets?

When you sell a long-term capital asset — say, listed shares or mutual fund units held for more than 12 months — the taxable gain isn’t calculated on face value. Instead, it’s adjusted for inflation using indexation.

The formula is simple:

Indexed Cost of Acquisition = (Original Cost × CII of Year of Sale) ÷ (CII of Year of Purchase)

You can also apply indexation to any improvement or additional investment made later, using the CII for the financial year when those costs were incurred. This approach ensures inflation is factored in before determining how much of your sale proceeds are considered actual profit for tax purposes.

Let’s understand this with an example.

(Resident individual, land acquired before 23 July 2024, sold in FY 2025–26)

Scenario

• A resident individual bought a plot of land in January 2016 (FY 2015–16) for ₹1,40,000.
  
• The land is sold in August 2025 (FY 2025–26) for ₹2,60,000.
  

Because:

1. The asset is land (immovable property),
   
2. It was acquired before 23-07-2024, and
   

It is held for more than 24/36 months (long-term),

The seller can choose between:

• 12.5% tax without indexation (new rule), or
  

20% tax with indexation (old rule, allowed under the grandfathering option).

Step 1 – Tax under the new 12.5% regime (no indexation)

• Long-term capital gain (without indexation)
  
  • Sale price: ₹2,60,000
    
  • Less: Cost of purchase: ₹1,40,000
    
  • Gain = ₹2,60,000 – ₹1,40,000 = ₹1,20,000
    
• Tax at 12.5% (no indexation)
  
  • Tax = 12.5% of ₹1,20,000
    
  • Tax = ₹15,000
    

Step 2 – Tax under the old 20% regime (with indexation)

Cost Inflation Index (CII) values:

• FY 2015–16 = 254
  
• FY 2025–26 = 376
  

• Indexed cost of acquisition
  
  • Indexed cost = Original cost × (CII of year of sale ÷ CII of year of purchase)
    
  • Indexed cost = ₹1,40,000 × (376 ÷ 254)
    
  • Indexed cost ≈ ₹2,07,244
    
• Long-term capital gain with indexation
  
  • Sale price: ₹2,60,000
    
  • Less: Indexed cost: ₹2,07,244
    
  • Indexed gain ≈ ₹52,756
    
• Tax at 20% with indexation
  
  • Tax = 20% of ₹52,756
    
  • Tax ≈ ₹10,551
    

Step 3 – Apply the grandfathering rule

Compare both options:

• New rule (12.5% without indexation) → Tax = ₹15,000
  

Old rule (20% with indexation) → Tax ≈ ₹10,551

Since the tax with indexation (₹10,551) is lower, the seller can choose the 20% with indexation option under the grandfathering provision for land/building acquired before 23 July 2024.

• Final tax payable on this transaction (after using CII and grandfathering): approximately ₹10,551.
  
• Taxable long-term capital gain after indexation: approximately ₹52,756.

Note: For transfers on or after 23 July 2024, long-term capital gains on most assets are taxed at 12.5% without indexation.

For land and buildings acquired before 23 July 2024, resident individuals and HUFs may choose between:

• 12.5% without indexation, or
  
• 20% with indexation (using the Cost Inflation Index),
  and can opt for whichever option results in lower tax. Indexation does not apply to listed equity and equity mutual funds under Section 112A.

Things to Note about Cost Inflation Index in India

If you’ve spent on improvements — say, renovating your house — you can combine the cost inflation index and improvement cost in India by applying the CII of the year the expense occurred.

Understanding how to use the cost inflation index in India is essential: identify the CII of the purchase year and sale year, use the formula, and compute your indexed cost correctly.

For assets bought before the base year, investors often wonder what happens if an asset was acquired before the base year under the cost inflation index in India. In such cases, you can take the FMV as of 1 April 2001 (if higher than the actual cost) and apply indexation from there.

Also, remember that the cost inflation index vs consumer price index in India are not the same. The CPI tracks consumer price movements, while the CII is a taxation tool for adjusting long-term asset values.

The Finance (No. 2) Act, 2024 has removed the indexation benefit for long-term capital assets and introduced a uniform long-term capital gains tax rate of 12.5% for all transfers made on or after 23 July 2024. This means indexation can no longer be used while computing long-term capital gains under the new regime. However, the government has provided a grandfathering relief specifically for resident individuals and resident HUFs. Under this provision, indexation can still be applied to land or buildings acquired before 23 July 2024, allowing taxpayers to compute tax at the earlier rate of 20% with indexation. This grandfathering option can be used only if the tax payable under the new law—12.5% without indexation—results in a higher tax liability.

Ultimately, the cost inflation index benefits in India are clear: it brings fairness, reduces tax liability, and aligns your capital gains tax with inflation-adjusted growth.

How Indexation Reduces LTCG Tax: A Simple Story

Consider Raj and Sita, who bought a plot of land in 2004 for ₹ 20 lakh. Two decades later, in 2024, they sell it for ₹ 1 crore. At first glance, that looks like an ₹ 80 lakh gain — but that’s nominal, not real.

Applying CII changes the picture:

• CII for FY 2004–05 = 113
  
• CII for FY 2024–25 = 363
  

Indexed cost = ₹ 20 lakh × (363 ÷ 113) ≈ ₹ 64.2 lakh
Taxable gain ≈ ₹ 35.8 lakh

So instead of paying tax on ₹ 80 lakh, they’re taxed on ₹ 35.8 lakh — a realistic figure once inflation is factored in.

As of November 2025, with the CII at 376 for FY 2025–26, this system continues to cushion taxpayers against inflation’s silent impact.

FAQs

Conclusion

In a country where inflation touches every pocket, understanding what is cost inflation index isn’t optional — it’s essential. The CII ensures that you’re taxed on real wealth creation, not on the illusion of nominal price rise.

As FY 2025–26 begins with a new CII of 376, indexation continues to be a key relief mechanism for investors and property owners. But as rules evolve, always check the latest CBDT notifications or consult a tax professional before filing returns.

Because while you can’t control inflation, you can make sure it doesn’t unfairly inflate your taxes.

Disclaimer

Investments in securities markets are subject to market risks. This content is for informational and educational purposes only and should not be construed as investment or tax advice. Past performance is not indicative of future results. Please consult a qualified financial or tax advisor before making investment decisions.