o3 vs Qwen3.5 Plus
Qwen3.5 Plus comes out ahead, 66 to 58 on our weighted score, and it is the cheaper option too.
OpenAIo3
58/100- ECI146.9
- Price$2.00 / $8.00
- Context200K
- Our pick
Alibaba (Qwen)Qwen3.5 Plus
66/100- ECI146.8
- Price$0.40 / $2.40
- Context1M
Add a model
Make it a three-way comparison.
Qwen3.5 Plus is our pick
Qwen3.5 Plus is the better all-round choice, scoring 66/100 against o3 (58). It leads on price and context window. o3 wins on inputs & features. The score weighs capability 50%, price 25%, inputs & features 15%, context window 10%.
- Capabilityo3Capabilities Index (ECI): o3 146.9 · Qwen3.5 Plus 146.8
- Lowest priceQwen3.5 PlusQwen3.5 Plus $0.90 · o3 $3.50 per 1M tokens (3:1 blend)
- Longest contextQwen3.5 PlusQwen3.5 Plus 1,000,000 · o3 200,000 tokens
- Widest inputsSame inputso3: Text, Images, PDFs · Qwen3.5 Plus: Text, Images, Video
- Self-hostingNo open weightsBoth are available only through APIs
| Measure | Weight | o3 | Qwen3.5 Plus |
|---|---|---|---|
| CapabilityCapabilities Index (ECI) | 50% | 74 | 74 |
| Price | 25% | 24 | 52 |
| Inputs & features | 15% | 80 | 70 |
| Context window | 10% | 32 | 60 |
| Overall | 100% | 58/100 | 66/100 |
Every spec in one table
Highlighted cells lead their row. Dashes mean the data is not published.
| Specification | o3OpenAI | Qwen3.5 PlusAlibaba (Qwen) |
|---|---|---|
| Capability | ||
| Capabilities Index (ECI) | 146.9 (best) | 146.8 |
| ECI rank | #63 of 148 (best) | #65 of 148 |
| GPQA DiamondGraduate-level science questions | 81.8% | 84.9% (best) |
| FrontierMath Tiers 1–3Research-level mathematics | 33.3% | — |
| OTIS Mock AIME 2024–2025Competition mathematics | 84.4% | 86.7% (best) |
| SWE-bench VerifiedFixing real GitHub issues | 62.3% | — |
| SimpleQA VerifiedShort factual questions | 49.4% (best) | 25.4% |
| Price per million tokens | ||
| Input | $2.00 | $0.40 (best) |
| Output | $8.00 | $2.40 (best) |
| Cached input | $0.50 | — |
| Blended (3:1) | $3.50 | $0.90 (best) |
| Long-context rate | Same rate | Same rate |
| Price source | Official OpenAI API | Official Alibaba API |
| Limits | ||
| Context window | 200,000 tokens | 1,000,000 tokens (best) |
| Max output | 100,000 tokens (best) | 65,536 tokens |
| Inputs and features | ||
| Text | Yes | Yes |
| Images | Yes | Yes |
| PDFs | Yes | No |
| Audio | No | No |
| Video | No | Yes |
| Reasoning | Yeslow · medium · high | Yes |
| Tool calling | Yes | Yes |
| Structured output | Yes | No |
| Availability | ||
| Weights | Proprietary | Proprietary |
| API model ID | o3 | qwen3.5-plus |
| API providers | 18 (best) | 10 |
| Released | Apr 16, 2025 | Feb 16, 2026 |
| Knowledge cutoff | May 2024 | Apr 2025 |
What would a month cost?
Enter your expected volume in millions of tokens. List prices only; caching and batch discounts would lower these.
- o3$36.00
- Qwen3.5 Plus$8.80
Which should you choose?
Which is better: o3 or Qwen3.5 Plus?
Qwen3.5 Plus is the better all-round choice, scoring 66/100 against o3 (58). It leads on price and context window. o3 wins on inputs & features. The score weighs capability 50%, price 25%, inputs & features 15%, context window 10%.
Which is cheaper, o3 or Qwen3.5 Plus?
Qwen3.5 Plus is cheaper at $0.40 input / $2.40 output per million tokens (official Alibaba API price). o3 costs $2.00 input / $8.00 output per million tokens (official OpenAI API price). At a typical mix of three input tokens to one output token, that is $0.90 per million tokens for Qwen3.5 Plus versus $3.50 for o3 (3.9× as much).
Which scores higher on benchmarks?
o3 scores higher on the Capabilities Index (ECI): o3 146.9 (#63 of 148) and Qwen3.5 Plus 146.8 (#65 of 148). The confidence ranges of the top two overlap (144.9–148.6 vs 144.6–148.1), so treat the gap as small. On individual benchmarks: GPQA Diamond — Qwen3.5 Plus 84.9%, o3 81.8%; OTIS Mock AIME 2024–2025 — Qwen3.5 Plus 86.7%, o3 84.4%; SimpleQA Verified — o3 49.4%, Qwen3.5 Plus 25.4%.
Which is better for coding?
There are no published SWE-bench Verified results for Qwen3.5 Plus yet, so there is no like-for-like coding score. On overall capability, o3 leads, which tends to carry over to coding, but test on your own codebase. Both support tool calling for agent workflows.
Which has the bigger context window?
Qwen3.5 Plus has the largest context window at 1,000,000 tokens, against 200,000 for o3. Maximum output per response: o3 up to 100,000, Qwen3.5 Plus up to 65,536 tokens.
Which can read images, PDFs, audio or video?
o3 accepts text, images and PDFs; Qwen3.5 Plus accepts text, images and video. They handle the same number of input types.
Are any of these open source?
No. o3 and Qwen3.5 Plus are proprietary and only available through APIs and apps.
Which is newer?
Qwen3.5 Plus is the newest, released Feb 16, 2026. o3 came out Apr 16, 2025. Knowledge cutoff: o3 May 2024, Qwen3.5 Plus Apr 2025.
How do you decide the winner?
Each model gets a 0–100 score on capability (50%, independent benchmark results); price (25%, blended price per million tokens (3 input : 1 output), log scale); inputs & features (15%, image, PDF, audio and video input, tool calling, structured output and reasoning); context window (10%, maximum tokens per request, log scale). Dimensions missing for any model are dropped and the remaining weights rescaled, so every model is judged on the same evidence. Specs and prices come from public model listings and the labs’ own API pages; capability scores come from independent benchmark runs. Data updated Oct 4, 2026.
Related comparisons
- Add Gemini 2.5 ProThree-way comparison
- o3 vs Gemini 2.5 ProGoogle · ECI 145.3
- o3 vs Claude Sonnet 4.5Anthropic · ECI 146.8
- o3 vs Qwen3 MaxAlibaba (Qwen) · ECI 142.4
- o3 vs GLM-5Z.ai (Zhipu) · ECI 145.8
- Qwen3.5 Plus vs MiniMax-M2.5MiniMax · ECI 146.7
- Qwen3.5 Plus vs Nemotron 3 Ultra 550B A55BNVIDIA · ECI 146.2
