Model comparison
gpt-oss-20b vs Gemini 2.5 Pro
- Input
- $0.029 / 1M tokens
- Output
- $0.14 / 1M tokens
- Context
- 131K
- Released
- 2025-08-05
- Input
- $1.25 / 1M tokens (prompts ≤200K); $2.50 / 1M tokens (prompts >200K)
- Output
- $10.00 / 1M tokens (prompts ≤200K); $15.00 / 1M tokens (prompts >200K)
- Context
- 1M
- Released
- 2025-03-25
Gemini 2.5 Pro scores higher on 3 of the 4 benchmarks both models report (the other leads on 1); gpt-oss-20b is cheaper on input tokens ($0 vs $1.3 per 1M, 43.1×); Gemini 2.5 Pro has the larger context window (1M vs 131K); gpt-oss-20b ships open weights while Gemini 2.5 Pro is API-only.
Specs and pricing side by side
| Spec | gpt-oss-20b | Gemini 2.5 Pro |
|---|---|---|
| Maker | OpenAI | |
| Released | 2025-08-05 | 2025-03-25 |
| Context window | 131K | 1M |
| Max output | 131K | 64K |
| Input price | $0.029 / 1M tokens | $1.25 / 1M tokens (prompts ≤200K); $2.50 / 1M tokens (prompts >200K) |
| Output price | $0.14 / 1M tokens | $10.00 / 1M tokens (prompts ≤200K); $15.00 / 1M tokens (prompts >200K) |
| Parameters | 20.9B total / 3.6B active (MoE) | Not disclosed |
| License | Apache 2.0 | Proprietary |
| Weights | Open weights | API only |
| Modalities | Text | Text, Vision, Audio, Video, PDF |
| Knowledge cutoff | June 2024 | January 2025 |
Benchmarks both models report
| Benchmark | gpt-oss-20b | Gemini 2.5 Pro |
|---|---|---|
| GPQA Diamond | 71.5% | 84% |
| AIME 2025 | 98.7% | 86.7% |
| SWE-bench Verified | 60.7% | 63.8% |
| Humanity's Last Exam | 17.3% | 18.8% |
Scores are as published by each maker or its cited source; harness, reasoning effort and date can differ between rows, so treat small gaps as ties. Sources are listed on each model page.
Which one should you pick?
Pick gpt-oss-20b if…
- You care about AIME 2025 (it scores higher on 1 shared benchmark).
- Cost matters: input tokens cost 43.1× less ($0 vs $1.3 per 1M).
- You want to self-host or fine-tune (open weights, Apache 2.0).
- Your use case is: on-device and local reasoning assistants that keep data off the cloud.
Pick Gemini 2.5 Pro if…
- You care about GPQA Diamond, SWE-bench Verified, Humanity's Last Exam (it scores higher on 3 shared benchmarks).
- You need the longer context (1M vs 131K).
- You need Vision / Audio / Video / PDF input, which gpt-oss-20b lacks.
- Your use case is: complex multi-step reasoning in math, science, and analysis.
FAQ
Which is better, gpt-oss-20b or Gemini 2.5 Pro?
Gemini 2.5 Pro scores higher on 3 of the 4 benchmarks both models report (the other leads on 1); gpt-oss-20b is cheaper on input tokens ($0 vs $1.3 per 1M, 43.1×); Gemini 2.5 Pro has the larger context window (1M vs 131K); gpt-oss-20b ships open weights while Gemini 2.5 Pro is API-only. The better pick depends on whether you value benchmark scores, price per token, context length or openness for your workload.
How much cheaper is gpt-oss-20b?
gpt-oss-20b: $0.029 / 1M tokens input, $0.14 / 1M tokens output. Gemini 2.5 Pro: $1.25 / 1M tokens (prompts ≤200K); $2.50 / 1M tokens (prompts >200K) input, $10.00 / 1M tokens (prompts ≤200K); $15.00 / 1M tokens (prompts >200K) output (list API prices as published by each maker).
What are the context windows of gpt-oss-20b and Gemini 2.5 Pro?
gpt-oss-20b offers 131K with up to 131K output; Gemini 2.5 Pro offers 1M with up to 64K output.
Is gpt-oss-20b newer than Gemini 2.5 Pro?
gpt-oss-20b was released 2025-08-05; Gemini 2.5 Pro was released 2025-03-25.