Claude Fable 5 vs GPT-5.4 Pro vs Claude Opus 4.5
Claude Fable 5 comes out ahead, 65 to 60 and 55 on our weighted score, though Claude Opus 4.5 is 2× cheaper per token.
- Our pick
AnthropicClaude Fable 5
65/100- ECI162.2
- Price$10.00 / $50.00
- Context1M
OpenAIGPT-5.4 Pro
60/100- ECI159.1
- Price$30.00 / $180.00
- Context1.05M
- Anthropic
Claude Opus 4.5
55/100- ECI150.1
- Price$5.00 / $25.00
- Context200K
Claude Fable 5 is our pick
Claude Fable 5 is the better all-round choice, scoring 65/100 against GPT-5.4 Pro (60) and Claude Opus 4.5 (55). It leads on capability. Claude Opus 4.5 wins on price. The score weighs capability 50%, price 25%, inputs & features 15%, context window 10%.
- CapabilityClaude Fable 5Capabilities Index (ECI): Claude Fable 5 162.2 · GPT-5.4 Pro 159.1 · Claude Opus 4.5 150.1
- Lowest priceClaude Opus 4.5Claude Opus 4.5 $10.00 · Claude Fable 5 $20.00 · GPT-5.4 Pro $67.50 per 1M tokens (3:1 blend)
- Longest contextGPT-5.4 ProGPT-5.4 Pro 1,050,000 · Claude Fable 5 1,000,000 · Claude Opus 4.5 200,000 tokens
- Widest inputsClaude Fable 5 and Claude Opus 4.5Claude Fable 5: Text, Images, PDFs · GPT-5.4 Pro: Text, Images · Claude Opus 4.5: Text, Images, PDFs
- Self-hostingNo open weightsAll three are available only through APIs
| Measure | Weight | Claude Fable 5 | GPT-5.4 Pro | Claude Opus 4.5 |
|---|---|---|---|---|
| CapabilityCapabilities Index (ECI) | 50% | 94 | 90 | 78 |
| Price | 25% | 0 | 0 | 2 |
| Inputs & features | 15% | 80 | 60 | 80 |
| Context window | 10% | 60 | 61 | 32 |
| Overall | 100% | 65/100 | 60/100 | 55/100 |
Every spec in one table
Highlighted cells lead their row. Dashes mean the data is not published.
| Specification | Claude Fable 5Anthropic | GPT-5.4 ProOpenAI | Claude Opus 4.5Anthropic |
|---|---|---|---|
| Capability | |||
| Capabilities Index (ECI) | 162.2 (best) | 159.1 | 150.1 |
| ECI rank | #7 of 148 (best) | #11 of 148 | #48 of 148 |
| GPQA DiamondGraduate-level science questions | 85.9% | 94.6% (best) | 86.1% |
| FrontierMath Tiers 1–3Research-level mathematics | 87.0% (best) | 82.5% | 34.4% |
| OTIS Mock AIME 2024–2025Competition mathematics | 100% (best) | — | 86.1% |
| SWE-bench VerifiedFixing real GitHub issues | — | — | 76.7% |
| SimpleQA VerifiedShort factual questions | 70.7% (best) | 46.3% | 45.7% |
| Price per million tokens | |||
| Input | $10.00 | $30.00 | $5.00 (best) |
| Output | $50.00 | $180.00 | $25.00 (best) |
| Cached input | $1.00 | — | $0.50 (best) |
| Blended (3:1) | $20.00 | $67.50 | $10.00 (best) |
| Long-context rate | Same rate | Over 272K: $60.00 / $270.00 | Same rate |
| Price source | Official Anthropic API | Official OpenAI API | Official Anthropic API |
| Limits | |||
| Context window | 1,000,000 tokens | 1,050,000 tokens (best) | 200,000 tokens |
| Max output | 128,000 tokens (best) | 128,000 tokens (best) | 64,000 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 | Yeslow · medium · high · xhigh · max | Yesmedium · high · xhigh | Yeslow · medium · high |
| Tool calling | Yes | Yes | Yes |
| Structured output | Yes | No | Yes |
| Availability | |||
| Weights | Proprietary | Proprietary | Proprietary |
| API model ID | claude-fable-5 | gpt-5.4-pro | claude-opus-4-5 |
| API providers | 38 (best) | 16 | 28 |
| Released | Jun 9, 2026 | Mar 5, 2026 | Nov 24, 2025 |
| Knowledge cutoff | Jan 31, 2026 | Aug 31, 2025 | May 2025 |
What would a month cost?
Enter your expected volume in millions of tokens. List prices only; caching and batch discounts would lower these.
- Claude Fable 5$200.00
- GPT-5.4 Pro$660.00
- Claude Opus 4.5$100.00
Which should you choose?
Which is better: Claude Fable 5, GPT-5.4 Pro or Claude Opus 4.5?
Claude Fable 5 is the better all-round choice, scoring 65/100 against GPT-5.4 Pro (60) and Claude Opus 4.5 (55). It leads on capability. Claude Opus 4.5 wins on price. The score weighs capability 50%, price 25%, inputs & features 15%, context window 10%.
Which is cheaper, Claude Fable 5, GPT-5.4 Pro or Claude Opus 4.5?
Claude Opus 4.5 is cheaper at $5.00 input / $25.00 output per million tokens (official Anthropic API price). Claude Fable 5 costs $10.00 input / $50.00 output per million tokens (official Anthropic API price); GPT-5.4 Pro costs $30.00 input / $180.00 output per million tokens (official OpenAI API price). At a typical mix of three input tokens to one output token, that is $10.00 per million tokens for Claude Opus 4.5 versus $20.00 for Claude Fable 5 (2× as much) and $67.50 for GPT-5.4 Pro (6.8× as much).
Which scores higher on benchmarks?
Claude Fable 5 scores higher on the Capabilities Index (ECI): Claude Fable 5 162.2 (#7 of 148), GPT-5.4 Pro 159.1 (#11 of 148) and Claude Opus 4.5 150.1 (#48 of 148). The confidence ranges of the top two overlap (159.6–166.1 vs 156.5–161.9), so treat the gap as small. On individual benchmarks: GPQA Diamond — GPT-5.4 Pro 94.6%, Claude Opus 4.5 86.1%, Claude Fable 5 85.9%; FrontierMath Tiers 1–3 — Claude Fable 5 87.0%, GPT-5.4 Pro 82.5%, Claude Opus 4.5 34.4%; SimpleQA Verified — Claude Fable 5 70.7%, GPT-5.4 Pro 46.3%, Claude Opus 4.5 45.7%.
Which is better for coding?
There are no published SWE-bench Verified results for Claude Fable 5 and GPT-5.4 Pro yet, so there is no like-for-like coding score. On overall capability, Claude Fable 5 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 Pro has the largest context window at 1,050,000 tokens, against 1,000,000 for Claude Fable 5 and 200,000 for Claude Opus 4.5. Maximum output per response: Claude Fable 5 up to 128,000, GPT-5.4 Pro up to 128,000, Claude Opus 4.5 up to 64,000 tokens.
Which can read images, PDFs, audio or video?
Claude Fable 5 accepts text, images and PDFs; GPT-5.4 Pro accepts text and images; Claude Opus 4.5 accepts text, images and PDFs. Claude Fable 5 handles the widest range of inputs.
Are any of these open source?
No. Claude Fable 5, GPT-5.4 Pro and Claude Opus 4.5 are proprietary and only available through APIs and apps.
Which is newer?
Claude Fable 5 is the newest, released Jun 9, 2026. GPT-5.4 Pro came out Mar 5, 2026; Claude Opus 4.5 came out Nov 24, 2025. Knowledge cutoff: Claude Fable 5 Jan 31, 2026, GPT-5.4 Pro Aug 31, 2025, Claude Opus 4.5 May 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.
