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Official sourcesSpecifications & API prices · checked Oct 9, 2026
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MODEL ARENA / SIDE BY SIDE

Claude Sonnet 5.5 vs GPT-6.1 Sol

Official specifications and direct API prices. Your task decides the right fit.

MODEL A
MODEL B
MODEL A
Anthropic

Claude Sonnet 5.5

Text and code workflows with adaptive thinking.

activeText outputVerified 2026-10-09
Context tokens1,000,000
Input / 1M$2.00
Output / 1M$10.00

Full specifications & sources

MODEL B
OpenAI

GPT-6.1 Sol

Coding and reasoning with a lower listed price than Astra.

activeText outputVerified 2026-10-09
Context tokens1,050,000
Input / 1M$2.00
Output / 1M$10.00

Full specifications & sources

A CLOSER LOOK / REVIEWED 2026-10-09

Claude Sonnet 5.5 vs GPT-6.1 Sol: integration & API costs

For an application integration, Sonnet 5.5 and GPT-6.1 Sol start with matching base input and output prices. The useful decision is how their documented interfaces and limits fit your workload.

Equal base prices need equal billing assumptions

The reviewed base rates are $2 input and $10 output per million text tokens for both models. Cache reads have their own rate and reasoning output is billable. Equal prices do not guarantee equal cost for the same text: tokenization, output length and request-tier conditions still matter.

Plan around the interface you will actually use

Sonnet's model ID is claude-sonnet-5-5 on Anthropic Messages; Sol's is gpt-6.1-sol on OpenAI Responses. The Developer view exposes verified feature support and keeps unverified fields explicit. An unknown capability here is a research gap, not proof that a provider lacks it.

Use a concrete acceptance test

Both document up to 128,000 output tokens, while their shared context windows differ. Before changing a coding or document workflow, compare required output formats, validation failures and task correctness on the same acceptance set. This page supplies cost and specification evidence, not an unsupported coding winner.

Official sources behind this guide

Documented specifications and standard direct API rates, manually checked 2026-10-09. Evaluation suggestions are editorial guidance; no measured comparative quality or speed is claimed.

Key differences

Everyday overview
Specification
SpecificationMODEL AClaude Sonnet 5.5MODEL BGPT-6.1 Sol
Shared context window1,000,0001,050,000
Input token limitNot verified922,000
Maximum output tokens128,000128,000
Accepted inputtext, imagetext, image
Outputtexttext
ReasoningSupportedSupported

Unknown fields are not evidence of equal capabilities. Specifications describe support, not comparative answer quality.

BENCHMARK EVIDENCE

No reliable data available

Comparable results with confirmed reuse permission have not been published here yet.

A published result must include the exact model version, benchmark version, original value and unit, test date, conditions and source. No scores or overall rankings are inferred.

Official API pricing

USD / 1M text tokens · Standard
Token rate / condition
Token rate / conditionMODEL AClaude Sonnet 5.5MODEL BGPT-6.1 Sol
Base input / 1M$2.00$2.00
Base output / 1M$10.00$10.00
Cached input read / 1M$0.10$0.10
Higher tier above input tokensNo tier documented272,000
Higher-tier input / 1MNot verified$4.00
Higher-tier output / 1MNot verified$15.00
Higher-tier cache read / 1MNot verified$0.20
Price review required afterNo expiry documentedNo expiry documented
MODEL A · Claude Sonnet 5.5

Official pricing source · verified 2026-10-09

Text tokens only. Output includes thinking tokens. Cache reads are a subset of input. Cache creation, tools and media fees are excluded.

MODEL B · GPT-6.1 Sol

Official pricing source · verified 2026-10-09

Text tokens only. Billable output includes reasoning tokens where applicable. Excludes cache creation, tools, media and regional or processing-tier uplifts.

Default 30-minute cache writes use 1.25× uncached input pricing as a replacement rate. V1 live trials request explicit-only caching with no breakpoints.

KNOW YOUR API COST

A small prompt. A clearer budget.

Same token counts for both models. Standard paid text rates in USD. Output must include all billable reasoning tokens.

Cached input is included in total input. No cache creation/storage, tools, media, taxes or regional/priority/Batch fees. Tokenizers differ; equal token counts do not imply equal text length.

OFFICIAL API COST ESTIMATEUSD
MODEL AClaude Sonnet 5.5
$7.000000

Base tier · Official rates · verified 2026-10-09

MODEL BGPT-6.1 Sol
$7.000000

Base tier · Official rates · verified 2026-10-09

Total API cost$14.000000
14 estimated credits / comparison14,000 credits across 1,000 comparisons.Reference estimate only. Playground uses verified OpenRouter charges; 1,000 credits = $1. A + B round up together once for each comparison.

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