PPI vs WPI: What is Producer Price Index and why will it replace Wholesale Price Index in India?
India has begun phasing out the Wholesale Price Index (WPI) in favour of a new Producer Price Index (PPI), aligning the country's price-statistics framework with practice in most advanced economies.
Both WPI and the new PPI are being released in parallel for five years from the date of the revised series' release, to let businesses and contracts referencing WPI transition smoothly.
Alongside the PPI launch, the WPI's own base year has been updated to 2022-23 (from 2011-12), with both revised indices covering an expanded basket of items.
Contracts, escalation clauses and long-term agreements that currently reference WPI will need to be recalibrated to the new index before WPI is eventually discontinued.
Producer Price Index vs Wholesale Price Index: Conceptual Difference
The WPI measures prices of goods at the first wholesale transaction point, capturing a mix of ex-factory, wholesale and, in places, import prices, and it excludes services entirely. The PPI, by contrast, measures the price received by the producer at the "factory gate" for output, excluding indirect taxes and trade margins, and is designed to include a Services PPI as well — a segment WPI never covered. This makes PPI conceptually closer to the value addition at the production stage and more comparable with PPIs used by the US, UK and other G20 economies.
Key Details
- The new framework includes an Output PPI (OPPI), a trial Input PPI (IPPI), and a Service PPI covering sectors such as banking, securities transactions, insurance, pension fund management, railways, air passenger transport and telecom.
- Both the revised WPI and the new PPI use 2022-23 as the base year, replacing the 2011-12 base, and cover an enlarged basket of items compared to the earlier series.
- The transition follows recommendations aligned with International Monetary Fund (IMF) methodological guidance and global best practice on producer price statistics.
The article explains precisely this shift — PPI is not merely a renamed WPI but a methodologically distinct index (factory-gate pricing, services coverage) that will eventually supersede WPI once the five-year parallel-run period ends.
Base Year Revision in Index Construction
Any price or production index (WPI, CPI, IIP) needs periodic base-year revision so that the "basket" of goods/services and their relative weights reflect current consumption/production patterns rather than an outdated economic structure. A stale base year understates or overstates inflation/growth because weights no longer match reality (e.g., digital goods, new services). Base revisions are typically undertaken by the compiling authority in consultation with an expert working group, followed by a back-series to preserve time-series comparability.
Key Details
- WPI base year has moved from 2011-12 to 2022-23; CPI's base year (2012=100) and IIP's base year (moved to 2022-23) are revised on a similar rationale by their respective custodians.
- WPI (like the new PPI) is compiled by the Office of Economic Adviser under the Department for Promotion of Industry and Internal Trade (DPIIT), Ministry of Commerce and Industry — distinct from CPI, which MoSPI compiles.
- A "back series" is released so analysts can compare pre- and post-revision data on a consistent base.
The simultaneous base-year revision (to 2022-23) alongside the WPI-to-PPI transition is a rare instance of both the index methodology and its reference base changing together, which is why the transition period and back series matter for contract recalibration.
- New base year for both the revised WPI and the new PPI: 2022-23 (replacing 2011-12).
- WPI will continue to be published in parallel with PPI for five years from the revised series' release date before being discontinued.
- The PPI framework introduces an Output PPI, a trial Input PPI, and a Service PPI (covering seven services including banking, insurance, railways, air passenger transport and telecom).
- Both indices are compiled by the Office of Economic Adviser, DPIIT, Ministry of Commerce and Industry.