The Submo AI Subscription Price Index

The index tracks the published US list price of one named plan per product. Where a vendor sells both an entry tier and a premium one, both are listed separately rather than averaged. Collapsing a $20 plan and a $200 plan into a single series would hide the only thing that has actually changed in this category.

The headline average covers the three entry tiers only. They are substitutes: people pick an assistant, they do not stack three. A premium tier is not a price increase on the entry tier, and this index does not treat it as one.

Microsoft 365 is tracked as the counter-example. It is not an AI assistant subscription, but in January 2025 Microsoft bundled Copilot into the consumer suite and raised the price 43% at the same time, the first increase in twelve years, and the clearest documented case of AI raising the price of a subscription people already had.

Prices are recorded in the month they took effect for new subscribers. Existing subscribers are typically moved one to two billing cycles later, so an individual bill may lag the series by a month or two.

Every price point cites the report that documented the change. When a report states a new price “up from $X”, or dates the previous increase, we treat that article as a record of the earlier point as well. Nothing is interpolated: a service holds its last documented price until the next documented change, which is why the chart steps rather than slopes.

It is based at February 2024, the month Google One AI Premium launched and the first month all three entry tiers were on sale at once. ChatGPT Plus had been charging $20 for a year by then, and has charged it ever since.

This category is young, and a flat line over two and a half years is a short record. Read it as “the entry price has not moved yet”, not as evidence that it will not.

It also tracks list prices only, and this is the category where that gap is widest: usage limits, rate caps and included model access have changed repeatedly underneath an unchanged price. Twenty dollars in 2023 and twenty dollars today do not buy the same thing, in either direction, and no price series can capture that.

Per-token API pricing, which is how most AI spending actually happens at scale, is out of scope entirely. This is a consumer subscription index.

It is US-only, and it contains no Submo user data of any kind. Every number on this page comes from public reporting, and can be checked against the sources below.