Compare / Claude Sonnet 4 vs Gemini 2.5 Flash
Claude Sonnet 4 vs Gemini 2.5 Flash
Which is cheaper, which is more capable, and which does better at each kind of work, from 15 results on 3 sources that measured both models.
Claude Sonnet 4 or Gemini 2.5 Flash? The short answer
- Gemini 2.5 Flash is cheaper: $0.85 against $6.00 per million tokens, 7.1 times less.
- Claude Sonnet 4 scores higher on the Artificial Analysis Intelligence Index: 18.9 against 13.1.
- On our business benchmarks, Claude Sonnet 4 ranks higher for reasoning and knowledge and writing.
- On our business benchmarks, Gemini 2.5 Flash ranks higher for agents and tool use and sticking to the facts.
At a glance
| Claude Sonnet 4 | Gemini 2.5 Flash | |
|---|---|---|
| Price per million tokens | $3.00 in · $15.00 out | $0.30 in · $2.50 out |
| Blended (3 in : 1 out) | $6.00 | $0.85 |
| Cheapest host, blended | $6.00 (Amazon Bedrock) | $0.42 (Google AI Studio) |
| Intelligence Index | 18.9 | 13.1 |
| Spring Prompt overall | – | – |
| Output speed, tokens a second | – | – |
| Context window | 200,000 tokens | 1,048,576 tokens |
| Weights | Closed | Closed |
| Developer based in | the US | the US |
Prices are the developer's list price where we have read it, otherwise the typical host on OpenRouter; see every model's price. Intelligence and speed from Artificial Analysis.
Which is better for what
Each model's rank among models available today, for each kind of work, from our own benchmarks and licensed sources. The better rank is in green.
| Use case | Claude Sonnet 4 | Gemini 2.5 Flash |
|---|---|---|
| Agents and tool useMulti-step tasks with tools: support desks, coding agents, function calls | 79 of 161 | 74 of 161 |
| Reasoning and knowledgeHard questions across science, maths and general knowledge | 111 of 195 | 115 of 195 |
| WritingWhat people prefer in blind comparisons, and judged writing quality | 68 of 187 | 93 of 187 |
| Sticking to the factsSummarising without inventing things, and factual answers | 88 of 153 | 66 of 153 |
Every shared result
| Benchmark | Metric | Claude Sonnet 4 | Gemini 2.5 Flash |
|---|---|---|---|
| Arena (formerly LMArena)reported | Business, management and financeArena rating | 1,387 | 1,399 |
| Arena (formerly LMArena)reported | Creative writingArena rating | 1,395 | 1,394 |
| Arena (formerly LMArena)reported | Expert promptsArena rating | 1,433 | 1,424 |
| Arena (formerly LMArena)reported | Instruction followingArena rating | 1,415 | 1,400 |
| Arena (formerly LMArena)reported | OverallArena rating | 1,402 | 1,409 |
| Arena (formerly LMArena)reported | Writing, literature and languageArena rating | 1,398 | 1,402 |
| Artificial Analysisreported | Artificial Analysis Intelligence Indexindex score | 18.9 | 13.1 |
| Artificial Analysisreported | GPQA Diamond% of questions | 77.7% | 79.0% |
| Artificial Analysisreported | Humanity's Last Exam% of questions | 10.7% | 12.1% |
| Artificial Analysisreported | IFBench% of instructions | 54.7% | 50.3% |
| Artificial Analysisreported | Long-context reasoning (AA-LCR)% of questions | 70.3% | 65.3% |
| Artificial Analysisreported | Terminal-Bench Hard% of tasks | 31.1% | 13.6% |
| Artificial Analysisreported | Τ²-bench telecom% of tasks | 64.6% | 31.6% |
| Vectara Hallucination Leaderboardreported | Answer rate% of documents | 98.6% | 99.0% |
| Vectara Hallucination Leaderboardreported | Hallucination rate% of summaries | 10.3% | 7.8% |
Bold green marks the better value on that metric. Where a source reports ranges that overlap, the difference may not be meaningful; see the benchmark page for ranges.
Quick answers
Is Claude Sonnet 4 better than Gemini 2.5 Flash?
It depends on the task. Among models available today, on our benchmarks and licensed sources, Claude Sonnet 4 ranks higher for reasoning and knowledge and writing; Gemini 2.5 Flash ranks higher for agents and tool use and sticking to the facts.
Which is cheaper, Claude Sonnet 4 or Gemini 2.5 Flash?
Gemini 2.5 Flash costs $0.85 per million tokens (three input to one output), against $6.00 for Claude Sonnet 4.
Run Claude Sonnet 4 and Gemini 2.5 Flash on your own prompt
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