Compare / Gemini 2.5 Flash vs o3
Gemini 2.5 Flash vs o3
Which is cheaper, which is more capable, and which does better at each kind of work, from 22 results on 3 sources that measured both models.
Gemini 2.5 Flash or o3? The short answer
- Gemini 2.5 Flash is cheaper: $0.85 against $3.50 per million tokens, 4.1 times less.
- o3 scores higher on the Artificial Analysis Intelligence Index: 20.2 against 13.1.
- On our business benchmarks, Gemini 2.5 Flash ranks higher for sticking to the facts.
- On our business benchmarks, o3 ranks higher for agents and tool use, reasoning and knowledge and writing.
At a glance
| Gemini 2.5 Flash | o3 | |
|---|---|---|
| Price per million tokens | $0.30 in · $2.50 out | $2.00 in · $8.00 out |
| Blended (3 in : 1 out) | $0.85 | $3.50 |
| Cheapest host, blended | $0.42 (Google AI Studio) | – |
| Intelligence Index | 13.1 | 20.2 |
| Spring Prompt overall | – | – |
| Output speed, tokens a second | – | 126 |
| Context window | 1,048,576 tokens | 200,000 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 | Gemini 2.5 Flash | o3 |
|---|---|---|
| Agents and tool useMulti-step tasks with tools: support desks, coding agents, function calls | 74 of 161 | 13 of 161 |
| Reasoning and knowledgeHard questions across science, maths and general knowledge | 115 of 195 | 95 of 195 |
| WritingWhat people prefer in blind comparisons, and judged writing quality | 93 of 187 | 49 of 187 |
| Sticking to the factsSummarising without inventing things, and factual answers | 66 of 153 | 91 of 153 |
Every shared result
| Benchmark | Metric | Gemini 2.5 Flash | o3 |
|---|---|---|---|
| Arena (formerly LMArena)reported | OverallArena rating | 1,437 | 1,405 |
| Arena (formerly LMArena)reported | Business, management and financeArena rating | 1,399 | 1,426 |
| Arena (formerly LMArena)reported | Creative writingArena rating | 1,394 | 1,383 |
| Arena (formerly LMArena)reported | Expert promptsArena rating | 1,424 | 1,449 |
| Arena (formerly LMArena)reported | Instruction followingArena rating | 1,400 | 1,403 |
| Arena (formerly LMArena)reported | OverallArena rating | 1,409 | 1,432 |
| Arena (formerly LMArena)reported | Writing, literature and languageArena rating | 1,402 | 1,396 |
| Artificial Analysisreported | Artificial Analysis Intelligence Indexindex score | 13.1 | 20.2 |
| Artificial Analysisreported | GPQA Diamond% of questions | 79.0% | 82.7% |
| Artificial Analysisreported | Humanity's Last Exam% of questions | 12.1% | 20.1% |
| Artificial Analysisreported | IFBench% of instructions | 50.3% | 71.4% |
| Artificial Analysisreported | Long-context reasoning (AA-LCR)% of questions | 65.3% | 74.7% |
| Artificial Analysisreported | Terminal-Bench Hard% of tasks | 13.6% | 37.1% |
| Artificial Analysisreported | Τ²-bench telecom% of tasks | 31.6% | 80.7% |
| Berkeley Function Calling Leaderboard (BFCL) V4reported | Irrelevance detection% correct | 93.7% | 86.1% |
| Berkeley Function Calling Leaderboard (BFCL) V4reported | Memory% correct | 41.3% | 51.8% |
| Berkeley Function Calling Leaderboard (BFCL) V4reported | Multi-turn tasks% correct | 36.2% | 62.2% |
| Berkeley Function Calling Leaderboard (BFCL) V4reported | Overall accuracy% correct | 56.2% | 63.0% |
| Berkeley Function Calling Leaderboard (BFCL) V4reported | Relevance detection% correct | 75.0% | 93.8% |
| Berkeley Function Calling Leaderboard (BFCL) V4reported | Single-turn calls (curated)% correct | 88.1% | 81.9% |
| Berkeley Function Calling Leaderboard (BFCL) V4reported | Single-turn calls (user-contributed)% correct | 78.2% | 73.2% |
| Berkeley Function Calling Leaderboard (BFCL) V4reported | Web search% correct | 62.0% | 77.0% |
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 Gemini 2.5 Flash better than o3?
It depends on the task. Among models available today, on our benchmarks and licensed sources, Gemini 2.5 Flash ranks higher for sticking to the facts; o3 ranks higher for agents and tool use, reasoning and knowledge and writing.
Which is cheaper, Gemini 2.5 Flash or o3?
Gemini 2.5 Flash costs $0.85 per million tokens (three input to one output), against $3.50 for o3.
Run Gemini 2.5 Flash and o3 on your own prompt
Benchmarks aren't your data. Try both side by side in the playground, with the cost of every answer.