Claude Fable 5 vs Claude Opus 5
Anthropic's Claude Fable 5 and Anthropic's Claude Opus 5 both target production language workloads, but they price and behave differently. Here is the side-by-side.
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The short answer
Claude Opus 5 is the cheaper option — roughly 2.0x less on a blended workload, and it suits most teams' best claude starting point. Claude Fable 5 justifies its premium when you need long-horizon agentic engineering.
Anthropic • Claude 5
$10.00 / $50.00
/ 1M tokens (input / output)
Anthropic's most capable widely released model, built for agents that run for hours rather than seconds. Adaptive thinking is always on and cannot be disabled, which is part of why it tops the Artificial Analysis Intelligence Index — and why its cost per task runs roughly triple GPT-5.6 Sol's for a one-point intelligence lead.
Anthropic • Claude 5
$5.00 / $25.00
/ 1M tokens (input / output)
A step change over Opus 4.8 on deep reasoning and long-horizon agentic work, at half Fable 5's price and with the freshest knowledge cutoff in the Claude line. Anthropic's own guidance is that most teams should benchmark Opus 5 before paying for Fable 5.
Input price
Claude Opus 5 is 50% cheaper than Claude Fable 5 on input tokens.
Output price
Claude Opus 5 is 50% cheaper than Claude Fable 5 on output tokens — usually the side that dominates the bill.
Monthly cost at three workload sizes
Standard (non-batch, non-cached) rates. Reasoning models will exceed these figures because thinking tokens bill as output.
| Workload | Claude Fable 5 | Claude Opus 5 | Difference |
|---|---|---|---|
| Light — 1M in / 200K out | $20 | $10 | $10 |
| Moderate — 10M in / 2M out | $200 | $100 | $100 |
| Heavy — 100M in / 20M out | $2,000 | $1,000 | $1,000 |
Specification comparison
| Attribute | Claude Fable 5 | Claude Opus 5 |
|---|---|---|
| Input (/ 1M tokens) | $10.00 | $5.00 |
| Output (/ 1M tokens) | $50.00 | $25.00 |
| Cached input | $1.00 | $0.50 |
| Context window | 1,000,000 tokens | 1,000,000 tokens |
| Max output | 128,000 tokens | 128,000 tokens |
| Native reasoning | Yes | Yes |
| Knowledge cutoff | 2026-01 | 2026-05 |
| Relative latency | high | medium |
| Open weights | No | No |
| API model ID | claude-fable-5 | claude-opus-5 |
| Status | stable | stable |
Claude Fable 5: 5-minute cache writes $12.50/MTok, 1-hour $20/MTok. Requires 30-day data retention, so not available under zero-data-retention terms.
Choose Claude Fable 5 if…
- Multi-hour autonomous coding runs
- Large codebase migrations
- Hard scientific workflows
- High-stakes legal and medical analysis
Choose Claude Opus 5 if…
- Agentic engineering with a cost ceiling
- Deep research and analysis
- Test-time compute scaling
- Production assistants needing recent knowledge
Frequently asked
Is Claude Fable 5 or Claude Opus 5 cheaper?
Claude Opus 5 is cheaper. On a blended 3:1 input-to-output workload it costs about 2.0x less than Claude Fable 5.
Which has the larger context window, Claude Fable 5 or Claude Opus 5?
Both accept up to 1M tokens, so context is not a differentiator here.
Should I use Claude Fable 5 or Claude Opus 5?
Pick Claude Fable 5 for long-horizon agentic engineering. Pick Claude Opus 5 for most teams' best claude starting point. If cost dominates the decision, Claude Opus 5 wins; if you need the capability ceiling, benchmark both on your own evals before committing.