Claude Sonnet 4.5 vs GPT-5 Nano
Benchmark Performance
Available Benchmarks
| Benchmark | Claude Sonnet 4.5 | GPT-5 Nano |
|---|---|---|
| ARC-AGI-1verified-v1-b2e2a31b3d53 · verified_score · leader | 63.67100% of row best · percent · Claude Sonnet 4.5 (Thinking 32K) | 20.7133% of row best · percent · GPT-5 Nano (Medium) |
| ARC-AGI-2verified-v2-326661568d5f · verified_score · leader | 13.61100% of row best · percent · Claude Sonnet 4.5 (Thinking 32K) | 2.6119% of row best · percent · GPT-5 Nano (High) |
| Berkeley Function Calling Leaderboardv4-ede5081a24bc · overall_accuracy · leader | 24.9090% of row best · percent · Claude-Sonnet-4-5-20250929 (Prompt) | 27.55100% of row best · percent · GPT-5-nano-2025-08-07 (Prompt) |
| LMArena Text Arenatext-2026-09-01-011508720696 · arena_rating · leader | 1,433.95100% of row best · rating · claude-sonnet-4-5-20250929-high-32k; 95% CI [1431.13754052, 1436.75329939]; votes 81031; rank 79 | 1,319.8492% of row best · rating · gpt-5-nano-high; 95% CI [1312.99438214, 1326.68844296]; votes 8128; rank 214 |
| ToneBench2026-08-28-10-task-cd9819ab6e4d · overall_score · leader | 77.25100% of row best · points · Claude Sonnet 4.5 · 2,441 output tokens / case | 61.6280% of row best · points · GPT-5 nano · 7,465 output tokens / case |
| Overall ResultCounted from the protocol-matched rows above | 4 benchmark winsOverall lead | 1 benchmark win |
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 4.5 | GPT-5 Nano |
|---|---|---|
| Developer | Anthropic | OpenAI |
| Family | Claude 4 | Gpt 5 |
| Model | Claude Sonnet 4.5 | GPT-5 Nano |
| Version | Claude Sonnet 4.5 | GPT-5 Nano |
| Lifecycle | active | active |
| Released | 2025-09-29 | 2025-08-07 |
| Knowledge cutoff | 2025-01-01 | 2024-05-31 |
| Input modalities | Text, Image | Text, Image |
| Output modalities | Text | Text |
| Context window | 200,000 | 400,000 |
| 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) | Openai (Standard), Openrouter (Standard) |
| Capabilities | chat, generation, reasoning, structured_outputs, tools | chat, generation, reasoning, structured_outputs, tools |
15 comparable fields · 8 material differences · Pair passes the primary-source comparison gate
Claude Sonnet 4.5 Capabilities
GPT-5 Nano Capabilities
Internal Comparison Graph
Related Comparisons
| A | Pair | B | Context |
|---|---|---|---|
Claude Sonnet 4.5Anthropic | vs | Claude Sonnet 4.6Anthropic | family variantsimage, text |
GPT-5 NanoOpenAI | vs | GPT-5.4 NanoOpenAI | family variantsimage, text |
Claude Opus 4.5Anthropic | vs | Claude Sonnet 4.5Anthropic | family variantsimage, text |
GPT-5 NanoOpenAI | vs | GPT-5.3-CodexOpenAI | family variantsimage, text |
Claude Sonnet 4.5Anthropic | vs | Claude Sonnet 5Anthropic | family variantsimage, text |
Claude Sonnet 4.5Anthropic | vs | o3OpenAI | cross-developer peersimage, text |
Claude Sonnet 4.5Anthropic | vs | o3-proOpenAI | cross-developer peersimage, text |
GPT-5 NanoOpenAI | vs | Grok 4.5xAI | cross-developer peersimage, text |
Claude Sonnet 4.5Anthropic | vs |  Qwen3 VL FlashQwen | cross-developer peersimage, text |
GPT-5 NanoOpenAI | vs | Qwen3 VL PlusQwen | cross-developer peersimage, text |
Claude Sonnet 4.5Anthropic | vs | GPT-5 ProOpenAI | cross-developer peersimage, text |
Claude Sonnet 4.5Anthropic | vs | GPT-5.3-CodexOpenAI | cross-developer peersimage, text |
Primary Evidence
Sources and Freshness
Questions
Claude Sonnet 4.5 vs GPT-5 Nano FAQs
Is Claude Sonnet 4.5 or GPT-5 Nano better for coding?+
This comparison does not currently contain a protocol-matched coding benchmark for both Claude Sonnet 4.5 and GPT-5 Nano, so Model Markets cannot name a coding leader from pricing, context size, or capability labels alone.
Which is cheaper, Claude Sonnet 4.5 or GPT-5 Nano?+
Claude Sonnet 4.5 is $3.00 and GPT-5 Nano is $0.025 per million tokens, so GPT-5 Nano is cheaper on this metric. Claude Sonnet 4.5 is $15.00 and GPT-5 Nano is $0.20 per million tokens, so GPT-5 Nano is cheaper on this metric.
Which has a larger context window, Claude Sonnet 4.5 or GPT-5 Nano?+
GPT-5 Nano has the larger sourced context window. Claude Sonnet 4.5 supports 200,000 and GPT-5 Nano supports 400,000.
Which performs better in benchmarks, Claude Sonnet 4.5 or GPT-5 Nano?+
Claude Sonnet 4.5 leads the current overall benchmark count. The result uses 5 protocol-matched benchmarks from 4 publishers; it is not a universal quality score.
Can Claude Sonnet 4.5 or GPT-5 Nano be self-hosted?+
Both models have the same recorded self-hosting status: unsupported. Claude Sonnet 4.5 is not marked open weight; GPT-5 Nano is not marked open weight.
Can Claude Sonnet 4.5 and GPT-5 Nano understand images?+
Claude Sonnet 4.5 is documented with image input; GPT-5 Nano is documented with image input. This reflects supported input modalities, not vision quality.
Which can generate longer answers, Claude Sonnet 4.5 or GPT-5 Nano?+
GPT-5 Nano has the larger sourced maximum output: Claude Sonnet 4.5 supports 64,000 and GPT-5 Nano supports 128,000 output tokens.
Do Claude Sonnet 4.5 and GPT-5 Nano support reasoning and tool use?+
Claude Sonnet 4.5: reasoning, tool calling, and image input. GPT-5 Nano: reasoning, tool calling, and image input. Feature support does not establish relative quality.
Which is available from more inference providers, Claude Sonnet 4.5 or GPT-5 Nano?+
Claude Sonnet 4.5 has 1 sourced provider route; GPT-5 Nano has 2, so GPT-5 Nano has broader tracked availability.
Which offers better value, Claude Sonnet 4.5 or GPT-5 Nano?+
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.