Claude Fable 5 vs GPT-5.6 Terra
Anthropic vs OpenAI · Prices checked 12 August 2026
GPT-5.6 Terra is the cheaper of the two by a wide margin: $5.00 per million tokens blended against $22.00, roughly 4.4× less. A single 100K-input, 10K-output job costs $0.320 on GPT-5.6 Terra against $1.50 on Claude Fable 5.
Across the 2 benchmarks both models report, they split the results evenly; neither has a clear capability edge on the public numbers. GPT-5.6 Terra takes a 1,050,000-token context window against 1,000,000, giving a modest edge for long documents or whole-codebase work.
Pricing and capacity
| Metric | Claude Fable 5 | GPT-5.6 Terra | Difference |
|---|---|---|---|
| Input / 1M tokens | $10.00 | $2.00 | 5.0× |
| Output / 1M tokens | $50.00 | $12.00 | 4.2× |
| Blended · 70/30calculated | $22.00 | $5.00 | 4.4× |
| Blended · 50/50calculated | $30.00 | $7.00 | 4.3× |
| Blended · 80/20calculated | $18.00 | $4.00 | 4.5× |
| Blended · 20/80calculated | $42.00 | $10.00 | 4.2× |
| Job cost · 100K + 10Kcalculated | $1.50 | $0.320 | 4.7× |
| Job cost · 1M + 100Kcalculated | $15.00 | $3.20 | 4.7× |
| Context window | 1,000,000 | 1,050,000 | 5% |
Input and output rates are as published by each provider. Blended and job-cost rows are calculated comparison metrics, not published prices — how they are derived.
Benchmarks
| Benchmark | Claude Fable 5 | GPT-5.6 Terra | Leader |
|---|---|---|---|
| GPQA Diamond | 95% | 92.9% | Claude Fable 5 |
| LMArena Elo | 1392 Elo | 1465 Elo | GPT-5.6 Terra |
Only suites both models report are listed, so a missing score is never shown as a loss. Figures are provider-published or from public leaderboards and are not independently re-run.
What each model is for
Claude Fable 5
Anthropic · Frontier
Anthropic's most powerful model, a new tier above Opus. Fable 5 keeps the 1M-token context window and multimodal input (text, image, file), and targets the hardest long-horizon agentic, coding and reasoning work. Priced at $10/$50 per MTok with $1.00 cached input.
- Most capable Claude to date
- State-of-the-art long-horizon agentic execution
- 1M-token context
- Text, image & file input
GPT-5.6 Terra
OpenAI · Balanced
The balanced everyday tier of GPT-5.6, which OpenAI describes as competitive with GPT-5.5 at a lower price. Terra is the cheaper path for scoped implementation work and first-pass review, where Sol's full reasoning budget is more than the task needs. Standard short-context pricing is $2/$12 per MTok with cached input at $0.20, roughly 60% below Sol for the same context window.
- GPT-5.5-class performance at lower cost
- Scoped implementation work
- First-pass code review
- Tool calling
Frequently asked questions
Which is cheaper, Claude Fable 5 or GPT-5.6 Terra?
GPT-5.6 Terra is the cheaper of the two by a wide margin: $5.00 per million tokens blended against $22.00, roughly 4.4× less. A single 100K-input, 10K-output job costs $0.320 on GPT-5.6 Terra against $1.50 on Claude Fable 5. Blended cost weights input at 70% and output at 30%; price your own token split for an exact answer, since the cheaper model on a blended basis is not always cheaper for your workload.
Which performs better, Claude Fable 5 or GPT-5.6 Terra?
Across the 2 benchmarks both models report, they split the results evenly; neither has a clear capability edge on the public numbers. These are the figures each provider or public leaderboard publishes, not results we re-run, and a benchmark average can hide the specific behaviour your workload depends on.
Which has the larger context window, Claude Fable 5 or GPT-5.6 Terra?
GPT-5.6 Terra takes a 1,050,000-token context window against 1,000,000, giving a modest edge for long documents or whole-codebase work. The context window caps everything in a single request: prompt, retrieved documents, conversation history and the model’s own output all share it.
Can I compare Claude Fable 5 and GPT-5.6 Terra on my own numbers?
Yes. Open both in the side-by-side comparison tool to see every field at once, or use the token calculator to price your actual prompt and monthly request volume against each model. Both are free and need no sign-up.
Price it for your own workload
Related matchups
Terms used on this page
Prices and scores are recomputed on every deploy from the catalogue. Prices checked 12 August 2026.