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LLM Toolkit

Model comparison

Claude Fable 5 vs GPT-5

Verified pricing, context windows and real-workload costs for both models — computed from official provider rates as of 2026-09-02.

Cheaper input

GPT-5

$1.25 /1M in

Cheaper output

GPT-5

$10.00 /1M out

Bigger context

Claude Fable 5

1M tokens

Head to head

Spec Claude Fable 5 GPT-5
Input / 1M tokens $10.00 $1.25
Cached input / 1M $1.00 $0.125
Output / 1M tokens $50.00 $10.00
Context window 1M 400K
Provider Anthropic OpenAI
Price verified 2026-09-02 2026-08-26

Monthly cost at three real workloads

Workload Claude Fable 5 GPT-5 Winner
Side-project chatbot 30K req · 2,000 in / 500 out · 40% cached $1,134/mo $198.00/mo GPT-5
Coding agent 500K req · 12,000 in / 1,500 out · 70% cached $59,700/mo $10,275/mo GPT-5
Bulk extraction 2,000K req · 800 in / 120 out · 20% cached $25,120/mo $4,040/mo GPT-5

Computed from list prices verified 2026-09-02. Cache savings blend normal and cached input rates by the hit rate; models without published cached rates use the base input price. Adjust every parameter yourself on the API Cost Calculator.

Pick Claude Fable 5 if…

  • You prefer its $10.00 input rate for read-heavy workloads.
  • You need the larger 1M context window.
  • You value its provider ecosystem and tooling.

Pick GPT-5 if…

  • You generate long outputs — $10.00 per 1M output vs $50.00 adds up fast.
  • Its 400K window covers your typical request with headroom.
  • You want cheaper total spend at your exact volumes — verify with the calculator above.

Frequently asked questions

Is Claude Fable 5 cheaper than GPT-5?

GPT-5 is cheaper on input at $1.25 per 1M tokens vs $10.00 — input pricing is 8.0× more expensive. On output, GPT-5 wins at $10.00 vs $50.00. At a balanced workload (100K requests, 2K in / 500 out), GPT-5 runs $750.00/mo vs $4,500/mo — a 6.0× difference.

Claude Fable 5 vs GPT-5: which has the bigger context window?

Claude Fable 5, with 1M tokens vs 400K — 2.5× more room. Filling Claude Fable 5's window once costs $10.00 at list price, vs $0.500 for the smaller window.

Should I switch from Claude Fable 5 to GPT-5?

Switch if your bottleneck matches GPT-5's strengths: its 400K context fits your documents and cheaper output tokens ($10.00 vs $50.00). Stay on Claude Fable 5 if your workload already fits its limits. Test both with your real token counts before committing.

Keep comparing

Or measure your real usage with the AI Token Counter and browse all rates on the Pricing Comparison.