On August 16, 2026, a post appeared on Reddit's r/codex claiming that Codex Plus's weekly cap may have effectively been cut in half. The poster, AppropriateRanger401, said that estimates from NerfTrack—a tool that reads local usage history—dropped from roughly $160 in the previous week to roughly $80 in the current week. If the figures are accurate and comparing like with like, this would represent an early detection of an anomaly in a flat-rate plan's weekly allowance.
However, as of August 21, OpenAI has not published numerical weekly caps for any of its plans, including Plus, and no official response to this post has been confirmed. Both the roughly $160 and roughly $80 figures are not billing amounts but estimates that NerfTrack converts using API pricing tables. It's necessary to separate what can be judged from a user's screen and what cannot.
From $160 to $80: The Change the Poster Claims
AppropriateRanger401 wrote that the previous week's estimate was about $160 and the current week's was about $80—a difference of about $80, or a 50% decrease week over week. The poster also claimed that usage dropped 40% in the first two days after the reset, followed by an additional 10% decrease.
Accounts in the comments section don't align. Some users say their usage on the 20x plan appears to have been cut roughly in half, while others report using up their Luna allowance on the $100 plan within two days, and still others claim usage appears to have doubled since August 9. Given that these user reports differ in model, usage pattern, and reset timing, it cannot be said that the same change affected all users across Plus, Pro 5x, and Pro 20x.
Still, for a service that doesn't disclose actual weekly cap numbers, attempts to convert usage history into a common yardstick have value. The question is how well that yardstick actually reflects the "weekly cap."
The $80 Figure Is an API-Converted Estimate, Not a Billed Amount
NerfTrack does not read, display, or convert Codex credits. Instead, it prices uncached input, cached input, and output tokens recorded in local JSONL files using API unit prices, then back-calculates a full-week API-equivalent amount from the ratio against the interval where the weekly usage rate increased. The formula is: estimated_weekly_api_equivalent_usd = cost_delta_usd / (percent_delta / 100).
For example, if the API-equivalent cost increased by $0.80 during an interval when the weekly used_percent rose by 1 percentage point, the estimate would be $0.80 divided by 0.01, yielding $80. This is an example illustrating the calculation method—not the poster's raw data. Nor does this figure represent the amount actually paid on a flat-rate ChatGPT plan, or the cost OpenAI internally allocates.
Per-model unit price differences are also significant. Under OpenAI's current API pricing—listed in order of input, cached input, and output per million text tokens—GPT-5.6 Sol costs $5.00, $0.50, and $30.00; Terra costs $2.00, $0.20, and $12.00; and Luna costs $0.20, $0.02, and $1.20. For requests exceeding 272,000 input tokens, input for the entire request doubles and output increases 1.5x. Cache writes also cost 1.25x uncached input.
NerfTrack's headline figure is the median of the latest seven valid cumulative estimates. Intervals are held or excluded when the cost delta is zero or negative, when there's no change in usage rate, when pricing is unknown, or when the interval crosses a reset boundary. Fast mode applies a 2.0x correction for GPT-5.4 and a 2.5x correction for GPT-5.5, GPT-5.6, and unknown future models—but only when an explicit configuration record exists. This means the dollar-converted value can shift even for the same weekly cap, depending on which model or settings were used.
Cross-Week Comparisons and Within-Week Corrections Are Different Things
NerfTrack's current comparison code requires that when comparing two points from different weekly epochs, both must have medium or high confidence, be finalized, not be heartbeat-based, and have a percentageCoverage of at least 10. Mature values from separate weeks that pass these conditions can serve as anomaly detection for cap changes—but only when the user's usage composition is similar across weeks.
On the other hand, values within the same epoch are not treated as comparable for calibration purposes. This calculation alone cannot distinguish between an estimator converging as usage history accumulates and the service actually changing the cap mid-week. The poster's claim of "a 40% drop followed by an additional 10%" does not constitute evidence that OpenAI reduced the cap in stages.
The original data and model configuration behind the posted screenshot have not been verified. Confidence level, percentageCoverage, epoch, and Fast mode settings are all unknown, and it's unclear whether the roughly $160 and roughly $80 figures were mature values that passed the comparison gate. If usage composition shifted—from reasoning-heavy tasks to image generation, for instance—the difference in API-equivalent amount cannot be attributed to the weekly cap alone.
What's Officially Documented Only Covers the 5-Hour Window
OpenAI's pricing page explains that local messages and cloud chat share a 5-hour window. The monthly prices for Plus, Pro 5x, and Pro 20x, along with approximate local message counts by model, are as follows. Regarding weekly limits, the page only states that "additional weekly limits may apply," without providing specific figures.
| Plan | Monthly Price | Sol (5-hour) | Terra (5-hour) | Luna (5-hour) |
|---|---|---|---|---|
| Plus | $20 | 10–100 | 25–200 | 250–2,000 |
| Pro 5x | From $100 | 50–500 | 125–1,000 | 1,250–10,000 |
| Pro 20x | $200 | 200–2,000 | 500–4,000 | 5,000–40,000 |
This table does not substantiate any claim about weekly caps. OpenAI itself explains that how much a single message consumes varies not only by model but also by usage conditions ranging from context to caching. Nor can the remaining weekly allowance be accurately estimated from prompt character count alone.
The publicly disclosed 5-hour window and the externally invisible weekly cap exist on separate layers. This is precisely why the roughly $80 estimate cannot be read at face value as "Plus's new official cap."
Verifying the Claim Requires Recording Specific Conditions
To properly investigate this report, one would need to measure multiple weeks using the same model, the same speed settings, and similar task composition. For each week, NerfTrack's confidence, percentageCoverage, and epoch would need to be disclosed, and only finalized values that passed the comparison gate should be compared against each other. Whether Fast mode was enabled is also a condition that cannot be omitted.
If OpenAI were to explain baseline weekly figures, whether any changes occurred, or how to interpret usage displays, this could be cross-checked against user-side estimates. Until official weekly figures exist, the key test for whether a single $80 reading can truly be called a halved cap is whether mature values under identical conditions repeatedly show a decline.