OpenAI still sells a 2022 embedding model at five times the price of its better replacement

Embedding models are the least glamorous part of an AI price list and the easiest to forget about once wired in. They turn text into vectors of numbers so that a system can measure how related two pieces of text are — the machinery behind search, clustering, recommendations and classification. Nobody demos them. They just sit in a pipeline and bill. Which is what makes the current OpenAI price list worth reading twice. **The same vector, one fifth of the money.** text-embedding-ada-002 shipped on 15 December 2022 and became the default of the early retrieval era. Its successors arrived on 25 January 2024. On OpenAI's own published figures, ada-002 scores 31.4% on MIRACL (multilingual retrieval) and 61.0% on MTEB (English); text-embedding-3-small scores 44.0% and 62.3%. Both produce 1,536-dimension vectors. The new one is better on both axes at the same output size — and is priced at $0.02 per million tokens against ada-002's $0.10. **The larger model makes the gap starker.** text-embedding-3-large reaches 54.9% on MIRACL and 64.6% on MTEB, at $0.13 per million tokens — three cents more than the model it replaced. And OpenAI notes something in the fine print of the 2024 announcement that is easy to miss: the new vectors can be truncated. Shortened to 256 dimensions, a text-embedding-3-large vector still beats a full 1,536-dimension ada-002 vector on MTEB. Six times smaller storage, better score, and still on the cheaper side of the comparison only if you count per token — per stored dimension it is not close. **Why the old model is still sold.** There is a real reason, and it is not sentiment. Embeddings are not portable between models: a vector from ada-002 and a vector from 3-small describe the same sentence in incompatible coordinate systems. Switching means re-embedding an entire corpus and rebuilding the index — for a large document store, a genuine engineering project. OpenAI has not announced a retirement date for ada-002, so nobody is being forced through that migration. The price difference is, in effect, what the vendor charges for not doing it. **A second, quieter case of a frozen price.** The same list holds TTS-1, OpenAI's first text-to-speech model. At launch on 6 November 2023 the company quoted $0.015 per 1,000 characters. Today it quotes $15 per million characters. Those are the same number: nearly three years, two generations of audio models, and no movement in either direction. **What this does not prove.** These are list prices for models that remain available, not evidence of anything hidden — OpenAI publishes all of it openly, and both older models still work exactly as documented. Nor is ada-002 a bad model; it was the best available when it shipped. The point is narrower and more practical: a default chosen in 2023 and never revisited is now the most expensive way to buy the weakest embeddings in the catalogue. wujec.ai has added profiles for all six models today, with the published benchmark figures side by side.