THE VERDICT
● GPT-5.6 Sol is now $4 / $20 per million, down from $5 / $30. Announced Friday 21 August.
● The catch: it lasts three months. Around 21 November it reverts unless OpenAI extends it.
● Claude Sonnet 5 goes the other way on 1 September — $2 / $10 becomes $3 / $15, plus a tokenizer change adding 10 to 35 percent tokens on code.
● Do not migrate on this alone. A three-month promo is not a reason to rewrite a production integration.
What actually changed
OpenAI said on Friday it is cutting developer pricing on its frontier model by more than 20 percent for the next three months, citing competition from Anthropic and Chinese labs.
| Model |
Input / 1M |
Output / 1M |
Note |
| GPT-5.6 Sol |
$4 (was $5) |
$20 (was $30) |
3 months only |
| GPT-5.6 Terra |
$2 |
$12 |
Cut 20% on 30 July |
| GPT-5.6 Luna |
$0.20 |
$1.20 |
Cut 80% on 30 July |
| Claude Sonnet 5 |
$2 → $3 |
$10 → $15 |
Rises 1 September |
| Claude Opus 5 |
$5 |
$25 |
Unchanged |
| Claude Fable 5 |
$10 |
$50 |
Unchanged |
| Grok 4.6 |
$2 |
$6 |
Doubles above 200K input |
The cut applies to the API and rolls out as credits across eligible ChatGPT Work and Codex plans. Pro, Plus and Business subscription pricing is unchanged. That split is deliberate — OpenAI is protecting consumer revenue while discounting for the usage-heavy developers most likely to test another stack.
Do not confuse this with last week's OpenRouter promo
TWO DIFFERENT THINGS, FOUR DAYS APART
On 18 August a Hacker News thread ran with "GPT-5.6 Sol Pricing Cut by 50%". That was an OpenRouter promo on non-BYOK traffic at an effective $2.50 / $15 — not an OpenAI change. OpenAI's own rate was untouched at the time.
Friday's announcement is the real thing: OpenAI's own rate card, $4 / $20, temporary.
The three-month clause is the whole story
A permanent cut and a three-month promotion produce identical spreadsheets and completely different decisions.
If you migrate a production workload to Sol on the strength of $4 / $20, you are betting the price holds past roughly 21 November. Nothing has been said about what happens then. The July cuts to Luna and Terra were framed as permanent, passing on serving efficiency gains. This one is explicitly for three months and explicitly attributed to competition.
That distinction tells you what it is: a customer-retention move aimed at developers currently evaluating Anthropic and the Chinese labs, not a change in what inference costs OpenAI to serve.
What the two directions actually mean
OpenAI cutting while Anthropic raises is not one company winning. It is two companies with different problems.
OpenAI is defending volume. It filed a confidential S-1 in June, its CFO committed to a 2027 listing this week, and reported figures put it near 2 billion dollars a month in revenue while losing roughly 1.22 dollars for every dollar earned. Developer count and usage growth are the metrics that matter in that story.
Anthropic is defending margin. It reported first operating profit of 559 million dollars on 10.9 billion in Q2 revenue, two years ahead of its own schedule. A company that has just proven it can be profitable raises prices; a company that needs a listing narrative buys usage.
What to actually do
| If you are... |
Do this |
| Already on Sol |
Nothing. Enjoy three months, diarise 21 November |
| On Sonnet 5, watching 1 September |
Model the tokenizer change too. On code the effective rise exceeds the 50% sticker |
| Tempted to migrate to Sol |
Price it at $5 / $30, the rate after November. If it still wins, migrate |
| Running high-volume cheap tasks |
Luna at $0.20 / $1.20 is a permanent cut and an order of magnitude below all of this |
| On a consumer subscription |
Unaffected. Pro, Plus and Business are unchanged |
| Undecided |
Route through an aggregator so the next repricing is a config change |
The general rule this fortnight keeps demonstrating: price a promotional rate at its post-promotional value. Migration costs engineering time, and three months of savings rarely covers it.
FAQ
What is GPT-5.6 Sol's new price?
4 dollars per million input tokens and 20 dollars per million output, for standard short-context use, down from 5 and 30. Announced Friday 21 August 2026.
How long does the cut last?
Three months, per OpenAI. That puts the revert around 21 November 2026 unless extended. No commitment beyond that has been made.
Does it affect ChatGPT Plus or Pro?
No. The cut applies to the API and to credits on eligible ChatGPT Work and Codex plans. Pro, Plus and Business subscription pricing is unchanged.
Is Claude now more expensive than GPT-5.6 Sol?
Depends which Claude. Opus 5 at 5 and 25 sits above Sol's promotional 4 and 20 but below its standard 5 and 30. Sonnet 5 stays cheaper even after rising to 3 and 15 on 1 September. Fable 5 at 10 and 50 is a different tier entirely.
Was there not a 50 percent Sol cut last week?
No. That was an OpenRouter promotion on non-BYOK traffic at an effective 2.50 and 15, widely misreported as an OpenAI price change. OpenAI's own rate was unchanged until Friday.
Should I switch from Claude to GPT-5.6 Sol?
Not on price alone, and not on a three-month price. Run your own eval on tasks you care about, then price the winner at post-promotional rates. A cheaper model that needs two attempts is not cheaper.