Claude Fable 5 vs GPT-5.6 Luna
Anthropic vs OpenAI · Prices checked 12 August 2026
On blended cost GPT-5.6 Luna undercuts Claude Fable 5 by about 44.0×: $0.500 per million tokens versus $22.00. A single 100K-input, 10K-output job costs $0.032 on GPT-5.6 Luna against $1.50 on Claude Fable 5.
On shared benchmarks it is a draw: 2 suites in common and honours even. On context, GPT-5.6 Luna is the larger at 1,050,000 tokens versus 1,000,000.
Pricing and capacity
| Metric | Claude Fable 5 | GPT-5.6 Luna | Difference |
|---|---|---|---|
| Input / 1M tokens | $10.00 | $0.200 | 50.0× |
| Output / 1M tokens | $50.00 | $1.20 | 41.7× |
| Blended · 70/30calculated | $22.00 | $0.500 | 44.0× |
| Blended · 50/50calculated | $30.00 | $0.700 | 42.9× |
| Blended · 80/20calculated | $18.00 | $0.400 | 45.0× |
| Blended · 20/80calculated | $42.00 | $1.00 | 42.0× |
| Job cost · 100K + 10Kcalculated | $1.50 | $0.032 | 46.9× |
| Job cost · 1M + 100Kcalculated | $15.00 | $0.320 | 46.9× |
| 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 Luna | Leader |
|---|---|---|---|
| GPQA Diamond | 95% | 92.3% | Claude Fable 5 |
| LMArena Elo | 1392 Elo | 1451 Elo | GPT-5.6 Luna |
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 Luna
OpenAI · Efficient
The fastest and most affordable GPT-5.6 tier, a deliberately low-reasoning lane for high-volume work where speed and cost are the binding constraints rather than depth. It keeps the family's 1M-token context window at $0.20/$1.20 per MTok, which is 25× cheaper than Sol on input, with cached input at $0.02.
- Lowest cost in the GPT-5.6 family, 25× cheaper input than Sol
- Fast responses
- High-volume throughput
- 1M-token context
Frequently asked questions
Which is cheaper, Claude Fable 5 or GPT-5.6 Luna?
On blended cost GPT-5.6 Luna undercuts Claude Fable 5 by about 44.0×: $0.500 per million tokens versus $22.00. A single 100K-input, 10K-output job costs $0.032 on GPT-5.6 Luna 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 Luna?
On shared benchmarks it is a draw: 2 suites in common and honours even. 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 Luna?
On context, GPT-5.6 Luna is the larger at 1,050,000 tokens versus 1,000,000. 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 Luna 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.