OpenAI's $100 Codex plan may have quietly lost 11% of its value

Bottom line

A careful user test points to an 11% reduction in the $100 Codex plan's effective weekly allowance. That looks like OpenAI trimming a heavily subsidized subscription, but one account cannot establish a universal policy change. The bigger problem is that OpenAI publishes a relative 5x promise, not a fixed weekly allowance, leaving paying users unable to audit changes.

OpenAI appears to be giving at least some $100 Codex subscribers less usage for the same monthly price.

That is the finding from one unusually careful user experiment shared on July 23. The user took more than 20 measurements on each of two test days, compared the change in Codex’s weekly usage meter with the tokens recorded by the open-source ccusage tool, and used linear regression to estimate the full allowance.

The result: the same $100 subscription appeared to fall from roughly $675 of API-equivalent weekly usage on July 13 to $600 on July 23.

That is a reduction of $75, or 11.1%, in ten days.

It is tempting to call this a confirmed price increase by stealth. The evidence does not support that conclusion yet. It comes from one account, may reflect an A/B test, and assumes Codex’s percentage meter maps consistently to API-equivalent token costs. OpenAI has not announced a broad 11% cut.

But the measurement exposes a real weakness in AI subscriptions: customers pay a fixed price for a usage allowance the vendor does not define in fixed units. If that hidden allowance changes, there is no public baseline against which to check it.

What the user actually measured

The original Reddit post is more rigorous than the usual “my limit feels worse” complaint.

The author, RealSuperdau, tracked the $100 Pro tier that Codex internally identifies as Pro Lite. On both July 13 and July 23, they ran heavy Codex tasks and repeatedly recorded two values:

the percentage of the weekly allowance still showing in Codex;
the API list-price equivalent of the input, cached input, and output tokens reported by ccusage.

They then fitted the observations to estimate the cost-equivalent value at which the weekly meter would reach zero.

Test date	Measurements	Observed sample	Estimated full weekly allowance
July 13	20+	About 28% of the meter and $193 API-equivalent	About $675
July 23	20+	About 16% of the meter and $96 API-equivalent	About $600

The author says alternative regression methods designed to account for Codex rounding its meter to whole percentages produced estimates within about $5 of each other.

They also tried to keep the workload comparable, using GPT-5.6 at high through ultra reasoning in non-fast mode, with occasional automatic fallback to GPT-5.5. That does not eliminate every variable, but it makes the result more useful than a comparison based on time spent in the app or number of prompts.

Why “API-equivalent” is not OpenAI’s actual cost

The $675 and $600 figures do not mean OpenAI paid those amounts to serve the account.

They represent what the recorded token mix would have cost a customer at published API rates. OpenAI’s underlying compute cost is lower than its retail API price, and a ChatGPT subscription can use different routing, caching, batching, or metering rules.

The comparison still matters because it holds the measuring stick constant. If similar work moved the same displayed weekly meter by more on July 23 than it did on July 13, the customer received less included usage even if the precise dollar conversion is imperfect.

This is best understood as a change in the plan’s implicit subsidy. At the earlier estimate, a power user could consume about 6.75 times the monthly subscription price in API-equivalent work every week. At the later estimate, that multiple fell to about 6 times.

The plan remains heavily discounted relative to buying the same measured tokens through the API. The complaint is not that $600 of weekly API-equivalent work is poor value for $100 a month. It is that the included value may be shrinking without a disclosed change to the product.

What OpenAI officially promises

OpenAI’s current plan documentation does not promise $675, $600, a token total, or any other fixed weekly allowance.

The company describes the $100 Pro tier as offering 5x more usage than Plus. Its Codex pricing page publishes estimated message ranges for five-hour windows, then adds that additional weekly limits may apply. It also explains that task consumption varies with the model, prompt size, codebase, task complexity, and where the task runs.

That wording gives OpenAI substantial room to rebalance the product. The $100 tier is defined relative to Plus, not by a fixed quantity of tokens, tasks, compute, or API-equivalent credit. If the Plus baseline or internal metering changes, the $100 plan can still be presented as 5x even while its absolute allowance falls.

Customers can see their remaining percentage in the Codex usage dashboard or with /status. They cannot see a published historical allowance for their tier or audit whether the denominator behind that percentage changed.

This is why the subsidy interpretation is persuasive. AI companies sold generous flat subscriptions to accelerate adoption of expensive agentic tools. As usage grows and users learn to keep agents running for longer, the vendor has three levers: raise prices, enforce stricter limits, or make each unit of included usage drain faster. Only the first is obvious on a billing page.

There are important reasons to be cautious

One user’s regression is evidence, not a global audit.

The author explicitly acknowledges that limits might differ between accounts or be part of an A/B test. The test windows also used different portions of the weekly meter, and Codex can change the model used during a task. An API-equivalent calculation may not perfectly match the internal weights OpenAI applies to different models, reasoning levels, speed settings, cached tokens, or tool use.

There is also a recent operational precedent that should not be confused with a deliberate plan cut. In late June, OpenAI investigated reports of Codex allowances depleting too quickly and said some accounts had been incorrectly rate-limited by abuse and fraud systems. OpenAI marked that incident resolved on June 29 and said it had not observed broader degradation.

That incident does not explain a July 13-to-July 23 decline. It does show that a meter draining faster can result from a bug or account-specific enforcement rather than an intentional commercial decision.

The strongest defensible conclusion today is narrow: this account’s measured effective weekly allowance fell by about 11%, and OpenAI’s public documentation does not give customers enough fixed information to determine why.

Why this matters beyond one Codex tier

Software subscriptions used to be easy to understand. You paid for a feature set, storage capacity, number of seats, or a clearly stated transaction allowance.

Agent subscriptions sell something less stable: a claim on future inference. The cost of fulfilling that claim changes with the model, reasoning depth, context length, tool calls, caching, and the user’s ability to run multiple long jobs. Providers want the simplicity of a flat monthly price without committing to a fixed amount of the expensive resource underneath it.

That creates a black-box contract:

the price is exact;
the advertised multiplier is relative;
the real allowance is hidden;
the meter is rounded;
and the vendor can change models or internal weights.

A reduction does not need to appear in the plan name or monthly bill. It can arrive as a task that used to consume 3% now consuming 4%, a weekly reset that lasts five days instead of six, or a model that is quietly weighted more heavily against the same percentage bar.

For individual users, that makes comparison shopping unusually difficult. For businesses building workflows around subscriptions, it makes capacity planning fragile. A workflow that fits comfortably within a plan this month may require top-up credits next month even when its prompts and output remain unchanged.

What OpenAI should publish

OpenAI does not need to guarantee unlimited use. It does need to make paid allowances legible.

A useful disclosure would include:

the fixed weekly credit or compute allowance for each plan;
the rate at which each model, reasoning level, and speed setting consumes it;
a dated history of allowance or weighting changes;
account-specific restrictions clearly separated from the standard plan limit;
unrounded usage data that customers can export;
advance notice when the effective included allowance is reduced.

OpenAI already has a credit rate card for usage beyond included limits. Extending that clarity to the subscription allowance would let users distinguish a policy change from a bug, a more expensive model, or an unusually heavy task.

The bottom line

The viral summary gets the direction right but overstates the certainty.

A $100 Codex subscriber produced a credible measurement showing that their weekly API-equivalent allowance declined from about $675 to $600 between July 13 and July 23. That is an 11.1% loss of effective included value while the subscription price stayed the same.

It looks like a reduction in OpenAI’s subscription subsidy. It is not yet proof that every $100 account was cut, nor proof that OpenAI deliberately changed the plan rather than testing new limits or mis-metering some users.

The part that is already confirmed is the transparency failure. OpenAI tells customers the tier offers 5x Plus usage, but it does not state a fixed weekly allowance. Until that changes, users are left reverse-engineering a product they pay $100 a month to use.