GPT-6.1 Sol → Claude Sonnet 5.5: cost and quality on real tasks
On the six tasks below, Claude Sonnet 5.5 from Anthropic costs about the same as GPT-6.1 Sol per request at list prices. So this switch is about quality, not price: it only lowers your real cost per result if it works first time more often.
Price per million tokens
Standard list prices, checked 2026-11-12. Prices change often, so check the source before you rely on them.
| Model | Input | Cached input | Output | Source |
|---|---|---|---|---|
| GPT-6.1 Sol (current)openai/gpt-6.1-sol | $2.00 | $0.10 | $10.00 | OpenAI's pricing page |
| Claude Sonnet 5.5 (new)anthropic/claude-sonnet-5.5 | $2.00 | $0.10 | $10.00 | Anthropic's pricing page |
- Note on GPT-6.1 Sol: Long context (>272K input tokens): $4 in / $0.20 cached / $15 out. Named replacement for gpt-5.1 / gpt-5.3-codex (retiring 2027-04-01).
- Note on Claude Sonnet 5.5: Cache hits priced at 0.05x input. Cache writes: 5m $2.50, 1h $4. Batch 50% off.
Cost per 1,000 results on six common tasks
What 1,000 requests cost at list price, for six task shapes from different kinds of app. The token counts are illustrative, not measured: your prompts may be longer or shorter, and the switch test below shows your real ones.
| Task, and what goes in and out | Tokens in / out | GPT-6.1 Sol | Claude Sonnet 5.5 | Change | Break-even: Claude Sonnet 5.5 costs no more per result that works if it works first time at least |
|---|---|---|---|---|---|
| Support bot answerInstructions, three help-centre passages and the customer's question in; a short answer out. | 3,000 / 300 | $9.00 | $9.00 | Same | as often as GPT-6.1 Sol |
| Invoice field extractionInstructions and one invoice's text in; about 15 fields as JSON out. | 2,500 / 250 | $7.50 | $7.50 | Same | as often as GPT-6.1 Sol |
| Lead scoringScoring rules and one lead's form answers in; a score and a one-line reason out. | 1,200 / 100 | $3.40 | $3.40 | Same | as often as GPT-6.1 Sol |
| Email reply draftInstructions and the email thread so far in; a reply of about 300 words out. | 1,500 / 400 | $7.00 | $7.00 | Same | as often as GPT-6.1 Sol |
| TranslationInstructions and about 500 words of text in; the same text in another language out. | 900 / 800 | $9.80 | $9.80 | Same | as often as GPT-6.1 Sol |
| Search re-rankingA search query and 20 result snippets in; the ids of the best five, in order, out. | 4,000 / 50 | $8.50 | $8.50 | Same | as often as GPT-6.1 Sol |
Real cost per result: when a switch really saves
Real cost per result is what you actually pay for each result that worked, counting the failed tries. A result that fails gets tried again, and you pay for both tries.
So the price per request is only half the answer. Claude Sonnet 5.5 costs no more per result that works as long as it works first time at least as often as GPT-6.1 Sol. That's the new cost divided by the current cost, shown for each task in the last column above.
Example, with a made-up rate
Say 8 in 10 of GPT-6.1 Sol's support bot answers work first time. You pay $9.00 for 1,000 tries and get 800 that work, a real cost of $11.25 per 1,000 support bot answers that work. Claude Sonnet 5.5 costs $9.00 for 1,000 tries, so it matches that real cost if 80% of its support bot answers work first time, and costs less if more do.
Quality: test it on your own requests
This page can't tell you whether Claude Sonnet 5.5 handles your requests as well as GPT-6.1 Sol, and we don't publish quality scores. Quality depends on your prompts and your inputs: a model that answers short English questions well can still fail on long invoices, odd layouts or other languages.
The free model switch test runs your prompt and up to 20 of your real inputs on both models with your own key, through each provider's own API or OpenRouter. You see the answers side by side with the tokens and cost of each, and mark which ones worked.
Test both models on your promptsWhat to compare
- Format: does JSON still parse with the same field names, for extraction and scoring?
- Length and tone: are support answers and email drafts as short and polite as before?
- Refusals: does Claude Sonnet 5.5 decline requests that GPT-6.1 Sol handled?
- Hard inputs: long documents, other languages and messy formatting, not just the easy cases.
- Token counts: OpenAI and Anthropic count tokens differently, so the same request can cost more or less than the table says. The test shows the real counts.
Questions
Is Claude Sonnet 5.5 cheaper than GPT-6.1 Sol?
Per request, they cost about the same. GPT-6.1 Sol lists at $2.00 per million input tokens and $10.00 per million output tokens; Claude Sonnet 5.5 lists at $2.00 and $10.00 (GPT-6.1 Sol: price checked 12 nov 2026; unchanged since we started tracking it; Claude Sonnet 5.5: price checked 12 nov 2026; unchanged since we started tracking it). Per result that works, it depends on how often each model works first time on your inputs: Claude Sonnet 5.5 costs no more per result that works as long as it works first time at least as often as GPT-6.1 Sol.
How do I work out the break-even for my own app?
Divide what a request costs on Claude Sonnet 5.5 by what it costs on GPT-6.1 Sol, using your real token counts. Claude Sonnet 5.5 is cheaper per result that works as long as its share of results that work first time, divided by GPT-6.1 Sol's, is above that number. The model switch test gives you the token counts and cost of each request on both models.
Will Claude Sonnet 5.5 work as well as GPT-6.1 Sol for my app?
Nobody can tell you that from a price table or a general benchmark, because it depends on your prompts and inputs. Run 10 to 20 of your real requests through both models with the free model switch test, using your own provider key, and compare the answers side by side before you switch any users.