Claude Fable 5 vs GPT-5.6 Terra — Side-by-side pricing
Side-by-side API pricing and tokenizer details for Claude Fable 5 (Anthropic) and GPT-5.6 Terra (OpenAI).
Side-by-side pricing
| Feature | Claude Fable 5 | GPT-5.6 Terra |
|---|---|---|
| Provider | Anthropic | OpenAI |
| Input (per 1M tokens) | $10.00 | $2.50 |
| Output (per 1M tokens) | $50.00 | $15.00 |
| Long-context pricing | Flat rate at any prompt size | Over 272K tokens: $5.00 in / $22.50 out |
| Context caching | Yes — 90% off cached tokens | Yes — 90% off cached tokens |
| Batch API discount | 50% off | 50% off |
| Context window | 1M tokens | 1.1M tokens |
| Tokenizer | Anthropic tokenizer (Opus 4.7+) | o200k_base (tiktoken) |
Real-world cost example
1,000 API requests per month, each with 500 input tokens and 200 output tokens (500K input + 200K output total).
Claude Fable 5
$15.0000
Input: $5.0000 +Output: $10.0000
GPT-5.6 Terra
$4.2500
Input: $1.2500 +Output: $3.0000
GPT-5.6 Terra is 72% cheaper for this workload — saving $10.7500 per month at this volume.
Frequently asked questions
No, GPT-5.6 Terra is cheaper for the typical workload above. At $2.50/1M input and $15.00/1M output tokens, it costs $4.2500 versus $15.0000 for Claude Fable 5 — a 72% difference. Note that GPT-5.6 Terra switches to long-context pricing above 272K prompt tokens, so for very long prompts this gap does not scale linearly.
Claude Fable 5 supports a 1M token context window. GPT-5.6 Terra supports a 1.1M token context window. A larger context window lets you include more text — documents, conversation history, or code — in a single API call.
Claude Fable 5 supports context caching (90% off repeated tokens). It offers a 50% Batch API discount. GPT-5.6 Terra supports context caching (90% off repeated tokens). It offers a 50% Batch API discount.
No, they use different tokenizers. Claude Fable 5 uses the Anthropic tokenizer (Opus 4.7+), while GPT-5.6 Terra uses o200k_base (tiktoken). Different tokenizers split text differently, so the same prompt will produce different token counts on each model — the effective cost difference may be larger or smaller than the per-token price difference alone suggests.
Claude Fable 5 (Anthropic): $10 input / $50 output per 1M tokens. GPT-5.6 Terra (OpenAI): $2.5 input / $15 output per 1M tokens. Rates shown before caching or batch discounts.
For an 80% output / 20% input workload — typical for code generation or long-form writing — Claude Fable 5 costs $42.0000 per 1M total tokens and GPT-5.6 Terra costs $12.5000. GPT-5.6 Terra is 70% cheaper for this pattern. For your exact ratio, paste a real prompt into the calculator above.
Claude Fable 5 has a 1M-token context window — approximately 750K words or ~3K pages of standard text. GPT-5.6 Terra has a 1.1M-token context window — approximately 788K words or ~3K pages. (Estimates assume ~0.75 words per token.)
Calculate costs for your actual prompt
Paste your prompt into the calculator and get exact token counts using each model's real tokenizer — all in your browser.
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