Gemini 2.5 Flash vs o4-mini
Gemini 2.5 Flash (2025) and o4-mini (2025) are frontier reasoning models from Google DeepMind and OpenAI. Gemini 2.5 Flash ships a 1m-token context window, while o4-mini ships a 200k-token context window. On MMLU PRO, Gemini 2.5 Flash leads by 5.2 pts. On pricing, Gemini 2.5 Flash costs $0.30/1M input tokens versus $1/1M for the alternative. This comparison covers specs, pricing, API access, capabilities, benchmarks, input and output token costs, and production fit for coding and agent workloads.
Gemini 2.5 Flash is ~233% cheaper at $0.30/1M; pay for o4-mini only for coding workflow support.
Decision scorecard
Local evidence first| Signal | Gemini 2.5 Flash | o4-mini |
|---|---|---|
| Best for | multimodal apps, tool-calling agents, and long-context analysis | reasoning-heavy apps, multimodal apps, and tool-calling agents |
| Decision fit | Coding, RAG, and Agents | Coding, RAG, and Agents |
| Context window | 1m | 200k |
| Cheapest output | $2.50/1M tokens | $4/1M tokens |
| Provider routes | 6 tracked | 4 tracked |
| Shared benchmarks | MMLU PRO leader | 6 shared |
Decision tradeoffs
- Gemini 2.5 Flash holds a shared-benchmark lead on MMLU PRO, ahead by 5.2 points.
- Gemini 2.5 Flash has the larger context window for long prompts, retrieval packs, or transcript analysis.
- Gemini 2.5 Flash has the lower cheapest tracked output price at $2.50/1M tokens.
- Gemini 2.5 Flash has broader tracked provider coverage for fallback and route flexibility.
- Local decision data tags Gemini 2.5 Flash for Coding, RAG, and Agents.
- o4-mini holds a shared-benchmark lead on LiveCodeBench, ahead by 11.1 points.
- o4-mini uniquely exposes Reasoning in local model data.
- Local decision data tags o4-mini for Coding, RAG, and Agents.
Monthly cost at traffic
Estimate token spend from the cheapest tracked input and output route or tier on this page.
Gemini 2.5 Flash
$865
Cheapest tracked route/tier: Google AI Studio
o4-mini
$1,800
Cheapest tracked route/tier: Replicate API
Estimated monthly gap: $935. Batch, cache, alternate speed tiers, and negotiated pricing are excluded from this local estimate.
Switch friction
- Provider overlap exists on OpenRouter, Replicate API, and Vercel AI Gateway; start route-level A/B tests there.
- o4-mini is $1.50/1M tokens higher on cheapest tracked output pricing, so quality gains need to justify the spend.
- o4-mini adds Reasoning in local capability data.
- Provider overlap exists on Replicate API, OpenRouter, and Vercel AI Gateway; start route-level A/B tests there.
- Gemini 2.5 Flash is $1.50/1M tokens lower on cheapest tracked output pricing before cache, batch, or negotiated discounts.
- Check replacement coverage for Reasoning before moving production traffic.
Specs
| Specification | ||
|---|---|---|
| Released | 2025-06-17 | 2025-04-16 |
| Context window | 1m | 200k |
| Parameters | — | — |
| Architecture | Decoder Only | Decoder Only |
| License | Proprietary | Proprietary |
| Openness | Proprietary | Proprietary |
| Weights | Not released | Not released |
| Code | Unknown | Unknown |
| Commercial use | Commercial use: conditional | Commercial use: conditional |
| Knowledge cutoff | 2025-01 | 2025-08 |
Pricing and availability
| Pricing attribute | Gemini 2.5 Flash | o4-mini |
|---|---|---|
| Input price | $0.30/1M tokens | $1/1M tokens |
| Output price | $2.50/1M tokens | $4/1M tokens |
| Providers |
Capabilities
| Capability | Gemini 2.5 Flash | o4-mini |
|---|---|---|
| Vision | Yes | Yes |
| Multimodal | Yes | Yes |
| Reasoning | No | Yes |
| JSON / Tool use | Yes | Yes |
| Structured outputs | Yes | Yes |
| Code execution | Yes | Yes |
| IDE integration | No | No |
| Computer use | No | No |
| Parallel agents | No | No |
Benchmarks
| Benchmark | Gemini 2.5 Flash | o4-mini |
|---|---|---|
| MMLU PRO | 88.4 | 83.2 |
| Google-Proof Q&A | 82.8 | 81.4 |
| LiveCodeBench | 76.2 | 87.3 |
| Massive Multi-discipline Multimodal Understanding | 79.7 | 81.6 |
| Aider Polyglot | 55.1 | 72.0 |
| BFCL | 56.2 | 53.2 |
Continue comparing
- Gemini 2.5 Flash vs o3 Deep Research
- Gemini 2.5 Flash vs Phi-4 Mini Flash Reasoning
- Gemini 2.5 Flash Live API vs o3 Deep Research
- Gemini 2.5 Pro Preview 05-06 vs o4-mini
- Gemini 2.5 Flash vs Grok 4
- DeepSeek V4 Pro vs Gemini 2.5 Flash
- Gemini 2.5 Flash vs Grok 4.3
- DeepSeek V4 Flash vs Gemini 2.5 Flash
- DeepSeek R1 vs Gemini 2.5 Flash
- DeepSeek R1 vs o4-mini
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Last reviewed: 2026-06-29. Data sourced from public model cards and provider documentation.