Claude Sonnet 4.5 vs GPT-5.4 mini vs o3
GPT-5.4 mini comes out ahead, 63 to 58 and 55 on our weighted score, and it is the cheaper option too.
AnthropicClaude Sonnet 4.5
55/100- ECI146.8
- Price$3.00 / $15.00
- Context200K
- Our pick
OpenAIGPT-5.4 mini
63/100- ECI148.8
- Price$0.75 / $4.50
- Context400K
- OpenAI
o3
58/100- ECI146.9
- Price$2.00 / $8.00
- Context200K
GPT-5.4 mini is our pick
GPT-5.4 mini is the better all-round choice, scoring 63/100 against o3 (58) and Claude Sonnet 4.5 (55). It leads on capability, price and context window. The score weighs capability 50%, price 25%, inputs & features 15%, context window 10%.
- CapabilityGPT-5.4 miniCapabilities Index (ECI): GPT-5.4 mini 148.8 · o3 146.9 · Claude Sonnet 4.5 146.8
- Lowest priceGPT-5.4 miniGPT-5.4 mini $1.69 · o3 $3.50 · Claude Sonnet 4.5 $6.00 per 1M tokens (3:1 blend)
- Longest contextGPT-5.4 miniGPT-5.4 mini 400,000 · Claude Sonnet 4.5 200,000 · o3 200,000 tokens
- Widest inputsClaude Sonnet 4.5 and o3Claude Sonnet 4.5: Text, Images, PDFs · GPT-5.4 mini: Text, Images · o3: Text, Images, PDFs
- Self-hostingNo open weightsAll three are available only through APIs
| Measure | Weight | Claude Sonnet 4.5 | GPT-5.4 mini | o3 |
|---|---|---|---|---|
| CapabilityCapabilities Index (ECI) | 50% | 74 | 77 | 74 |
| Price | 25% | 13 | 39 | 24 |
| Inputs & features | 15% | 80 | 70 | 80 |
| Context window | 10% | 32 | 44 | 32 |
| Overall | 100% | 55/100 | 63/100 | 58/100 |
Every spec in one table
Highlighted cells lead their row. Dashes mean the data is not published.
| Specification | Claude Sonnet 4.5Anthropic | GPT-5.4 miniOpenAI | o3OpenAI |
|---|---|---|---|
| Capability | |||
| Capabilities Index (ECI) | 146.8 | 148.8 (best) | 146.9 |
| ECI rank | #64 of 148 | #56 of 148 (best) | #63 of 148 |
| GPQA DiamondGraduate-level science questions | 82.3% | 86.9% (best) | 81.8% |
| FrontierMath Tiers 1–3Research-level mathematics | 23.9% | 51.2% (best) | 33.3% |
| OTIS Mock AIME 2024–2025Competition mathematics | 77.8% | 88.9% (best) | 84.4% |
| SWE-bench VerifiedFixing real GitHub issues | 71.3% (best) | — | 62.3% |
| SimpleQA VerifiedShort factual questions | 30.7% | 29.4% | 49.4% (best) |
| Price per million tokens | |||
| Input | $3.00 | $0.75 (best) | $2.00 |
| Output | $15.00 | $4.50 (best) | $8.00 |
| Cached input | $0.30 | $0.075 (best) | $0.50 |
| Blended (3:1) | $6.00 | $1.69 (best) | $3.50 |
| Long-context rate | Same rate | Same rate | Same rate |
| Price source | Official Anthropic API | Official OpenAI API | Official OpenAI API |
| Limits | |||
| Context window | 200,000 tokens | 400,000 tokens (best) | 200,000 tokens |
| Max output | 64,000 tokens | 128,000 tokens (best) | 100,000 tokens |
| Inputs and features | |||
| Text | Yes | Yes | Yes |
| Images | Yes | Yes | Yes |
| PDFs | Yes | No | Yes |
| Audio | No | No | No |
| Video | No | No | No |
| Reasoning | Yes | Yeslow · medium · high · xhigh | Yeslow · medium · high |
| Tool calling | Yes | Yes | Yes |
| Structured output | Yes | Yes | Yes |
| Availability | |||
| Weights | Proprietary | Proprietary | Proprietary |
| API model ID | claude-sonnet-4-5 | gpt-5.4-mini | o3 |
| API providers | 28 | 29 (best) | 18 |
| Released | Sep 29, 2025 | Mar 17, 2026 | Apr 16, 2025 |
| Knowledge cutoff | Jul 31, 2025 | Aug 31, 2025 | May 2024 |
What would a month cost?
Enter your expected volume in millions of tokens. List prices only; caching and batch discounts would lower these.
- Claude Sonnet 4.5$60.00
- GPT-5.4 mini$16.50
- o3$36.00
Which should you choose?
Which is better: Claude Sonnet 4.5, GPT-5.4 mini or o3?
GPT-5.4 mini is the better all-round choice, scoring 63/100 against o3 (58) and Claude Sonnet 4.5 (55). It leads on capability, price and context window. The score weighs capability 50%, price 25%, inputs & features 15%, context window 10%.
Which is cheaper, Claude Sonnet 4.5, GPT-5.4 mini or o3?
GPT-5.4 mini is cheaper at $0.75 input / $4.50 output per million tokens (official OpenAI API price). o3 costs $2.00 input / $8.00 output per million tokens (official OpenAI API price); Claude Sonnet 4.5 costs $3.00 input / $15.00 output per million tokens (official Anthropic API price). At a typical mix of three input tokens to one output token, that is $1.69 per million tokens for GPT-5.4 mini versus $3.50 for o3 (2.1× as much) and $6.00 for Claude Sonnet 4.5 (3.6× as much).
Which scores higher on benchmarks?
GPT-5.4 mini scores higher on the Capabilities Index (ECI): GPT-5.4 mini 148.8 (#56 of 148), o3 146.9 (#63 of 148) and Claude Sonnet 4.5 146.8 (#64 of 148). The confidence ranges of the top two overlap (147.1–150.5 vs 144.9–148.6), so treat the gap as small. On individual benchmarks: GPQA Diamond — GPT-5.4 mini 86.9%, Claude Sonnet 4.5 82.3%, o3 81.8%; FrontierMath Tiers 1–3 — GPT-5.4 mini 51.2%, o3 33.3%, Claude Sonnet 4.5 23.9%; OTIS Mock AIME 2024–2025 — GPT-5.4 mini 88.9%, o3 84.4%, Claude Sonnet 4.5 77.8%; SimpleQA Verified — o3 49.4%, Claude Sonnet 4.5 30.7%, GPT-5.4 mini 29.4%.
Which is better for coding?
There are no published SWE-bench Verified results for GPT-5.4 mini yet, so there is no like-for-like coding score. On overall capability, GPT-5.4 mini leads, which tends to carry over to coding, but test on your own codebase. All three support tool calling for agent workflows.
Which has the bigger context window?
GPT-5.4 mini has the largest context window at 400,000 tokens, against 200,000 for Claude Sonnet 4.5 and 200,000 for o3. Maximum output per response: Claude Sonnet 4.5 up to 64,000, GPT-5.4 mini up to 128,000, o3 up to 100,000 tokens.
Which can read images, PDFs, audio or video?
Claude Sonnet 4.5 accepts text, images and PDFs; GPT-5.4 mini accepts text and images; o3 accepts text, images and PDFs. Claude Sonnet 4.5 handles the widest range of inputs.
Are any of these open source?
No. Claude Sonnet 4.5, GPT-5.4 mini and o3 are proprietary and only available through APIs and apps.
Which is newer?
GPT-5.4 mini is the newest, released Mar 17, 2026. Claude Sonnet 4.5 came out Sep 29, 2025; o3 came out Apr 16, 2025. Knowledge cutoff: Claude Sonnet 4.5 Jul 31, 2025, GPT-5.4 mini Aug 31, 2025, o3 May 2024.
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.
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