Head to head · prices checked 15 October 2026

Claude Opus 5.5 vs GPT-6.1 Sol

There is no quality verdict yet: the AIGROW small-business benchmark has not run either model. On price, GPT-6.1 Sol costs less: $2 in and $10 out per million tokens, against $4 in and $20 out for Claude Opus 5.5.

What a job costsEvery model

US dollars, standard rate, shortest context band. Price only: the benchmark has not run both.

1,000 support replies
2×what Claude Opus 5.5 costs next to GPT-6.1 Sol
Claude Opus 5.5
$20.00
GPT-6.1 Sol
$10.00
Claude Opus 5.5, per M tokens
$4 / $20
GPT-6.1 Sol, per M tokens
$2 / $10

3,000 tokens in and 400 out each, at list price.

Two models pitched at complex coding work, with Sol at half the Opus price. 1,000 support replies cost $20.00 on Claude Opus 5.5 and $10.00 on GPT-6.1 Sol, so Claude Opus 5.5 costs twice as much. Claude Opus 5.5 was released on 22 Sep 2026, GPT-6.1 Sol was released on 29 Sep 2026.

What each one costs

The API price per million tokens and the cheapest app plan with each model, from the makers’ own pages. Each name opens that model’s full price page.

Claude Opus 5.5
On the Anthropic API, Claude Opus 5.5 costs $4 per million input tokens and $20 per million output tokens. In Claude, the cheapest plan with it is Pro at $20/mo. Plan prices read 20 October 2026. AIGROW API credit runs Claude Opus 5.5 at $1.00 / $5.00 per million input / output tokens, up to 75% below list price. See API credit
GPT-6.1 Sol
On the OpenAI API, GPT-6.1 Sol costs $2 per million input tokens and $10 per million output tokens. In ChatGPT, the cheapest plan with it is Plus at $20/mo. Plan prices read 14 October 2026. AIGROW API credit runs GPT-6.1 Sol at $1.00 / $6.25 per million input / output tokens, up to 50% below list price. See API credit

Side by side

Each maker’s published rate for its standard tier. Cached input is what a repeated prompt prefix costs once the provider has stored it.

Claude Opus 5.5 and GPT-6.1 Sol: list prices and specifications
FactClaude Opus 5.5GPT-6.1 Sol
MakerAnthropicOpenAI
TierFlagshipsWorkhorses
Input, per M tokens$4.00$2.00
Output, per M tokens$20.00$10.00
Cached input$0.20$0.10
Context window1M1.05M
Released22 Sep 202629 Sep 2026
WeightsClosed weightsClosed weights

What a job costs on each

1,000 runs of each job at the two list prices. The gap moves from job to job because the models price input, output and cached context differently.

Cost of 1,000 runs of three jobs on Claude Opus 5.5 and GPT-6.1 Sol
JobClaude Opus 5.5GPT-6.1 SolCheaper
Support reply3,000 in, 400 out.$20.00$10.00GPT-6.1 Sol, 50% less
Document summary25,000 in, 1,000 out.$120$60.00GPT-6.1 Sol, 50% less
Agent task80,000 in (70,000 cached), 3,000 out.$114$57.00GPT-6.1 Sol, 50% less

The token counts are ours, chosen to look like real work; the prices are the makers’. A model with no published cache price bills the agent task’s repeated context at its full input rate.

The small print

What each base rate leaves out, from the makers’ own pages: surcharges, discounts, promotions and cache pricing.

Claude Opus 5.5
Cache read is 0.05x input on this model ($0.20). Cache write $5 (5 min) or $8 (1 h). Fast mode $8 / $40. Batch API 50% off. US-only inference bills 1.1x. Full context window billed at standard rates. Max output 128K. Anthropic’s pricing page
GPT-6.1 Sol
OpenAI recommends it to balance intelligence and cost. Requests above 272K input tokens bill 2x input and 1.5x output ($4 / $15, cached $0.20). Cache write $2.50. Batch and Flex 50% off, Fast mode 2x, Ultrafast mode $12 / $60. Data residency adds 10%. Context 1,050,000 with max input 922K. OpenAI’s pricing page

Other comparisons

Every head to head on the list that involves Claude Opus 5.5 or GPT-6.1 Sol.

Run both up to 75% below list price

AIGROW API credit covers Claude Opus 5.5 and GPT-6.1 Sol at published rates never above the list prices here, and $25 buys $100 of credit.

See API creditCompare every model

Prices checked 15 October 2026