Price Deflation Index
What is price deflation index?
The Price Deflation Index tracks how much cheaper a model has become relative to January 2023 baselines. GPT-4o-mini has a PDI of 0.25 — meaning it costs 99.75% less than the equivalent capability in January 2023. This is the metric that makes the AI cost revolution concrete and trackable over time. sourc.dev computes PDI for every model with both a current price and a historical baseline.
Why it matters
AI pricing has collapsed faster than any technology in history. GPT-4o-mini costs 99.75% less than the equivalent capability in January 2023. The Price Deflation Index makes this concrete and trackable per model. When you see a PDI of 4.17 for GPT-4o, that means it costs 4.17% of the January 2023 baseline. This is the number that tells investors and planners how fast the floor is falling.
Where models stand
Data available for 13 of 271 tracked entities. Last updated 2026-03-31.
How sourc.dev tracks this
sourc.dev verifies price deflation index manually from official provider documentation, API responses, and published specifications. Every data point includes a source URL and verification date. When a value changes, the old value is preserved in the history table and the new value is recorded alongside it. Nothing is overwritten — the full timeline is always available.
sourc.dev verifies this attribute manually from provider documentation. Every data point includes a source URL and verification date. Changes are recorded in the history table — nothing is overwritten.
This attribute is verified periodically against provider documentation. When sourc.dev detects a change, the new value is recorded alongside the old one with full provenance.
Understanding price deflation index helps developers make informed decisions when choosing between models and providers. Rather than relying on marketing claims, sourc.dev provides verified, dated, source-linked data so the data decides.