Claude Sonnet 4.5 vs Gemini 2.5 Flash
At a Glance
| Compare | Claude Sonnet 4.5Anthropic |  Gemini 2.5 FlashGoogle DeepMind |
|---|---|---|
| Intelligence, Cost, and Efficiency | ||
| IntelligenceHigher is better · MM Intelligence v2.5 | #36 of 4627.7 score · 2/3 sources · provisional · missing LiveBench · full-core range 18.5–51.8 | UnrankedNot in the 46-model eligible cohort |
| Pricing and Limits | ||
| Input priceFrom · USD / 1M tokens | $3.00Anthropic ↗ · Sep 3, 2026 | $0.30Google AI ↗ · Aug 29, 2026 |
| Output priceFrom · USD / 1M tokens | $15.00Anthropic ↗ · Sep 3, 2026 | $2.50Google AI ↗ · Aug 29, 2026 |
| Context windowMaximum documented tokens | 200K | 1,049K |
| Model facts checked | Sep 3, 2026View model evidence → | Aug 29, 2026View model evidence → |
Token prices are the lowest available sourced USD rates; input and output may use different providers. Cost ranking estimates output spend on LiveBench, not a full request bill. Ranking methodology →
Available Benchmarks
| Benchmark | Claude Sonnet 4.5 | Gemini 2.5 Flash |
|---|---|---|
| Berkeley Function Calling Leaderboardv4-ede5081a24bc · overall_accuracy · leader | 24.9049% of row best · percent · Claude-Sonnet-4-5-20250929 (Prompt) | 50.90100% of row best · percent · Gemini-2.5-Flash (Prompt) |
| LMArena Text Arenatext-2026-09-13-d25aabda0010 · arena_rating · leader | 1,433.94100% of row best · rating · claude-sonnet-4-5-20250929-high-32k; 95% CI [1431.13982742, 1436.74901697]; votes 80980; rank 81 | 1,417.2799% of row best · rating · gemini-2.5-flash; 95% CI [1414.83704531, 1419.70406968]; votes 122732; rank 116 |
| ToneBench2026-09-11-10-task-4ef099199c9c · overall_score · unverified | 77.25100% of row best · points · Claude Sonnet 4.5 · 7,415 output tokens / case | 72.1793% of row best · points · Gemini 2.5 Flash · 4,399 output tokens / case |
| Overall ResultCounted from the protocol-matched rows above | 1 benchmark winNo overall winner | 1 benchmark winNo overall winner |
Third-party benchmark Only like-for-like primary-publisher results are shown; raw scores, relative scores, configuration, and token spend remain visible.
Side-by-Side Facts
| Field | Claude Sonnet 4.5 | Gemini 2.5 Flash |
|---|---|---|
| Developer | Anthropic | Google DeepMind |
| Family | Claude 4 | Gemini 2 5 |
| Model | Claude Sonnet 4.5 | Gemini 2.5 Flash |
| Version | Claude Sonnet 4.5 | Gemini 2.5 Flash |
| Lifecycle | active | active |
| Released | 2025-09-29 | Unknown |
| Knowledge cutoff | 2025-01-01 | 2025-01-01 |
| Input modalities | Text, Image | Text, Image, Video, Audio |
| Output modalities | Text | Text |
| Context window | 200K | 1,049K |
| 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) | Google AI (Standard), Google Gemini (Standard) |
| Capabilities | chat, generation, reasoning, structured_outputs, tools | chat, generation, reasoning, tools |
Claude Sonnet 4.5 Capabilities
Gemini 2.5 Flash Capabilities
Related Comparisons
All text comparisons →| A | Pair | B | Context |
|---|---|---|---|
Claude Sonnet 4.5Anthropic | vs |  GPT-6 AstraOpenAI | cross-developer peersimage, text |
Claude Fable 5.1Anthropic | vs | Claude Sonnet 4.5Anthropic | family variantsimage, text |
Claude Sonnet 4.5Anthropic | vs | Gemini 3.1 ProGoogle DeepMind | cross-developer peerstext |
Claude Sonnet 4.5Anthropic | vs |  DeepSeek-V4.1-FlashDeepSeek | cross-developer peersimage, text |
Claude Sonnet 4.5Anthropic | vs | Grok 4.6xAI | cross-developer peersimage, text |
Claude Sonnet 4.5Anthropic | vs |  Qwen3.8-MaxQwen | cross-developer peersimage, text |
Claude Sonnet 4.5Anthropic | vs |  Kimi-K3Moonshot AI | cross-developer peersimage, text |
 MiniMax-M3MiniMax | vs | Claude Sonnet 4.5Anthropic | cross-developer peersimage, text |
Claude Sonnet 4.5Anthropic | vs |  GLM-5.3Z.ai | cross-developer peerstext |
Claude Sonnet 4.5Anthropic | vs |  Hy4 previewTencent | cross-developer peerstext |
Claude Sonnet 4.5Anthropic | vs | Seed 2.1 ProByteDance Seed | cross-developer peersimage, text |
Claude Sonnet 4.5Anthropic | vs |  Mistral Large 3Mistral AI | cross-developer peersimage, text |
Primary Evidence
Sources and Freshness
Questions
Claude Sonnet 4.5 vs Gemini 2.5 Flash FAQs
Is Claude Sonnet 4.5 or Gemini 2.5 Flash better for coding?+
This comparison does not currently contain a protocol-matched coding benchmark for both Claude Sonnet 4.5 and Gemini 2.5 Flash, so Model Markets cannot name a coding leader from pricing, context size, or capability labels alone.
Which is cheaper, Claude Sonnet 4.5 or Gemini 2.5 Flash?+
Claude Sonnet 4.5 is $3.00 and Gemini 2.5 Flash is $0.30 per million tokens, so Gemini 2.5 Flash is cheaper on this metric. Claude Sonnet 4.5 is $15.00 and Gemini 2.5 Flash is $2.50 per million tokens, so Gemini 2.5 Flash is cheaper on this metric.
Which has a larger context window, Claude Sonnet 4.5 or Gemini 2.5 Flash?+
Gemini 2.5 Flash has the larger sourced context window. Claude Sonnet 4.5 supports 200K and Gemini 2.5 Flash supports 1,049K.
Which performs better in benchmarks, Claude Sonnet 4.5 or Gemini 2.5 Flash?+
There is no overall benchmark winner: The verified common benchmarks do not produce a majority winner.
Can Claude Sonnet 4.5 or Gemini 2.5 Flash be self-hosted?+
Both models have the same recorded self-hosting status: unsupported. Claude Sonnet 4.5 is not marked open weight; Gemini 2.5 Flash is not marked open weight.
Can Claude Sonnet 4.5 and Gemini 2.5 Flash understand images?+
Claude Sonnet 4.5 is documented with image input; Gemini 2.5 Flash is documented with image input. This reflects supported input modalities, not vision quality.
Which can generate longer answers, Claude Sonnet 4.5 or Gemini 2.5 Flash?+
Gemini 2.5 Flash has the larger sourced maximum output: Claude Sonnet 4.5 supports 64K and Gemini 2.5 Flash supports 66K output tokens.
Do Claude Sonnet 4.5 and Gemini 2.5 Flash support reasoning and tool use?+
Claude Sonnet 4.5: reasoning, tool calling, and image input. Gemini 2.5 Flash: 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 Gemini 2.5 Flash?+
Claude Sonnet 4.5 has 1 sourced provider route; Gemini 2.5 Flash has 2, so Gemini 2.5 Flash has broader tracked availability.
Which offers better value, Claude Sonnet 4.5 or Gemini 2.5 Flash?+
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.