The cost index is a single number showing how much construction costs have changed at a city versus a base date (base = 100). CPWD calculates it as a weighted blendof key materials and labour, and revises it every 6 months. Apply it as: adjusted rate = base rate × (index ÷ 100).
The CPWD Building Cost Index (BCI) is how a rate prepared at one point in time is adjusted to today's costs at a particular city. This guide explains what the index actually measures, how CPWD calculates it, and how you apply it to a DSR or Plinth Area Rate.
What the cost index means
A schedule of rates or a Plinth Area Rate (PAR) is prepared using prices from a fixed base date. Construction costs then move — cement, steel, and labour all change over time and differ from city to city. The cost index is a single number that answers: compared to the base date, how much have construction costs changed at this station?
A base value of 100 represents the reference date. An index of 125 means costs at that station are 25% higher than the base. CPWD publishes the index for each station/city, and revises it twice a year — on 1st April and 1st October.
How CPWD calculates the index
The index is not a single price — it is a weighted blend of the main cost components of a typical building. CPWD tracks a basket of roughly a dozen items (cement, steel, bricks, sand, aggregate, labour, and so on). Each item is given a weightage reflecting how much it contributes to a typical building's cost, so the index isn't distorted by any single premium material.
For each item in the basket, the contribution to the index is:
CI per item = Weightage × ( Current proportionate value ÷ Base proportionate value )The current market rate of each item is compared with its base-period rate to get its proportionate value, multiplied by that item's weightage, and the contributions are summed. The result is the overall cost index for that station for that half-year.
The main index families
| Index | What it applies to |
|---|---|
| Building Cost Index (BCI) | General building works / Plinth Area Rates |
| 10CC | Cost index used for civil and electrical (E&M) escalation |
| 10CA | Related escalation index used in CPWD contracts |
How to apply the cost index to a rate
Once you have the correct station index, applying it is straightforward. To bring a base-date rate to the current cost at a city:
Adjusted rate = Base rate × ( Cost index ÷ 100 )For example, a Plinth Area Rate of ₹20,000/m² at base 100, applied at a station with cost index 125:
The same principle adjusts DSR-based estimates for the location and period of your project.
Why it matters for tenders
Using the wrong index — an outdated period or the wrong station — is one of the most common estimation errors, and it directly changes the tender value. Because CPWD revises the index every six months, always confirm you are using the current notification for the correct station before finalising an estimate.
Look up live values: BCI, 10CC and 10CA figures, ready to use.
Open Cost Indices