Claude Sonnet 5 vs GPT-5.5
Benchmark Performance
Available Benchmarks
| Benchmark | Claude Sonnet 5 | GPT-5.5 |
|---|---|---|
| LMArena Agent Arenaagent-2026-08-31-011508720696 · outcome_score · statistical tie | 7.48100% of row best · score · Claude Sonnet 5 (High); 95% CI [5.31247081, 9.65098366]; sessions 27467; observations 2696236; rank 8 | 4.8498% of row best · score · GPT 5.5; 95% CI [3.96340788, 5.71819765]; sessions 77762; observations 1908513; rank 18 |
| LMArena Document Arenadocument-2026-07-30-011508720696 · arena_rating · statistical tie | 1,470.2299% of row best · rating · claude-sonnet-5-high; 95% CI [1459.84859101, 1480.59820001]; votes 3601; rank 14 | 1,480.30100% of row best · rating · gpt-5.5; 95% CI [1473.46488383, 1487.13183487]; votes 17286; rank 9 |
| LMArena Text Arenatext-2026-09-01-011508720696 · arena_rating · leader | 1,442.9598% of row best · rating · claude-sonnet-5-high; 95% CI [1438.22001632, 1447.67497803]; votes 31096; rank 56 | 1,466.80100% of row best · rating · gpt-5.5; 95% CI [1462.99653821, 1470.60035247]; votes 64686; rank 27 |
| LMArena Vision Arenavision-2026-08-27-011508720696 · arena_rating · leader | 1,277.9499% of row best · rating · claude-sonnet-5-high; 95% CI [1269.73992861, 1286.14906472]; votes 8522; rank 29 | 1,294.36100% of row best · rating · gpt-5.5-high; 95% CI [1287.65516407, 1301.05910249]; votes 20121; rank 18 |
| Overall ResultCounted from the protocol-matched rows above · 2 ties | 0 benchmark wins | 2 benchmark winsOverall lead |
Third-party benchmark Only like-for-like primary-publisher results are shown; raw scores, relative scores, configuration, and token spend remain visible.
Technical Differences
Side-by-Side Facts
| Field | Claude Sonnet 5 | GPT-5.5 |
|---|---|---|
| Developer | Anthropic | Openai |
| Family | Claude 5 | Gpt 5 5 |
| Model | Claude Sonnet 5 | GPT-5.5 |
| Version | Claude Sonnet 5 | GPT-5.5 |
| Lifecycle | active | active |
| Released | 2026-06-30 | 2026-04-23 |
| Knowledge cutoff | Unknown | 2025-12-01 |
| Input modalities | Unknown | Unknown |
| Output modalities | Unknown | Unknown |
| Context window | 1,000,000 | 1,050,000 |
| Total parameters | Unknown | Unknown |
| Active parameters | Unknown | Unknown |
| License | Unknown | Unknown |
| Open weights | No | No |
| API available | Yes | Yes |
| Self-hostable | No | No |
| Provider access | Anthropic (Standard), Deepinfra (Standard), Openrouter (Standard) | Openai (Standard), Openrouter (Standard) |
| Capabilities | chat, generation, reasoning, tools | chat, generation, reasoning, structured_outputs, tools |
12 comparable fields · 8 material differences · Interactive comparison only; indexing gate not met
Claude Sonnet 5 Capabilities
GPT-5.5 Capabilities
Internal Comparison Graph
Related Comparisons
| A | Pair | B | Context |
|---|---|---|---|
Claude Fable 5.1Anthropic | vs | Claude Sonnet 5Anthropic | family variantsimage, text |
Claude Mythos 5.1Anthropic | vs | Claude Sonnet 5Anthropic | family variantsimage, text |
GPT-5.4OpenAI | vs | GPT-5.5OpenAI | family variantsimage, text |
GPT-5.4 ProOpenAI | vs | GPT-5.5OpenAI | family variantsimage, text |
GPT-5.1OpenAI | vs | GPT-5.5OpenAI | family variantsimage, text |
Claude Sonnet 4.6Anthropic | vs | Claude Sonnet 5Anthropic | family variantsimage, text |
Claude Sonnet 4.5Anthropic | vs | Claude Sonnet 5Anthropic | family variantsimage, text |
Claude Opus 4.6Anthropic | vs | GPT-5.5OpenAI | cross-developer peersimage, text |
Claude Opus 4.7Anthropic | vs | GPT-5.5OpenAI | cross-developer peersimage, text |
GPT-5.5OpenAI | vs | cross-developer peersimage, text | |
GPT-5.5OpenAI | vs | GPT-5.6 SolOpenAI | family variantsimage, text |
Claude Sonnet 5Anthropic | vs |  Qwen3.7 FlashQwen | cross-developer peersimage, text |
Primary Evidence
Sources and Freshness
Questions
Claude Sonnet 5 vs GPT-5.5 FAQs
Is Claude Sonnet 5 or GPT-5.5 better for coding?+
This comparison does not currently contain a protocol-matched coding benchmark for both Claude Sonnet 5 and GPT-5.5, so Model Markets cannot name a coding leader from pricing, context size, or capability labels alone.
Which is cheaper, Claude Sonnet 5 or GPT-5.5?+
Claude Sonnet 5 is $2.00 and GPT-5.5 is $5.00 per million tokens, so Claude Sonnet 5 is cheaper on this metric. Claude Sonnet 5 is $10.00 and GPT-5.5 is $30.00 per million tokens, so Claude Sonnet 5 is cheaper on this metric.
Which has a larger context window, Claude Sonnet 5 or GPT-5.5?+
GPT-5.5 has the larger sourced context window. Claude Sonnet 5 supports 1,000,000 and GPT-5.5 supports 1,050,000.
Which performs better in benchmarks, Claude Sonnet 5 or GPT-5.5?+
There is no overall benchmark winner: An overall winner requires at least two decisive benchmarks from at least two original publishers.
Can Claude Sonnet 5 or GPT-5.5 be self-hosted?+
Both models have the same recorded self-hosting status: unsupported. Claude Sonnet 5 is not marked open weight; GPT-5.5 is not marked open weight.
Can Claude Sonnet 5 and GPT-5.5 understand images?+
Claude Sonnet 5 is not documented with image input; GPT-5.5 is not documented with image input. This reflects supported input modalities, not vision quality.
Which can generate longer answers, Claude Sonnet 5 or GPT-5.5?+
Neither has a larger sourced maximum output. Claude Sonnet 5 is 128,000 and GPT-5.5 is 128,000.
Do Claude Sonnet 5 and GPT-5.5 support reasoning and tool use?+
Claude Sonnet 5: reasoning and tool calling. GPT-5.5: reasoning and tool calling. Feature support does not establish relative quality.
Which is available from more inference providers, Claude Sonnet 5 or GPT-5.5?+
Claude Sonnet 5 has 3 sourced provider routes; GPT-5.5 has 2, so Claude Sonnet 5 has broader tracked availability.
Which offers better value, Claude Sonnet 5 or GPT-5.5?+
There is no universal value winner. Compare the input and output prices above with the matched benchmark result for your workload: cheaper tokens can be offset by different quality, token usage, latency, or provider availability.