Fable 5 vs GPT-5.1: token pricing & cost compared (July 2026)

How Fable 5 (Anthropic) and GPT-5.1 (OpenAI) actually compare on price — input, output, and total monthly cost at the MAU you care about. Updated against live OpenRouter pricing.

Anthropic

Fable 5

Input: $10.00 / 1M tokens
Output: $50.00 / 1M tokens
Output / Input ratio: 5.0×
Context window: 1,000K

OpenAI

GPT-5.1

Input: $1.25 / 1M tokens
Output: $10.00 / 1M tokens
Output / Input ratio: 8.0×
Context window: 400K

The short answer

GPT-5.1 is cheaper across the board for typical workloads.

Token pricing side-by-side

Fable 5
GPT-5.1

Cost at your usage

Avg input tokens / call

Avg output tokens / call

Calls per active user / day: 5

Active days / month: 20

MAU: 1,000

Fable 5

Per call

$0.03000

Per user / mo

$3.0000

Total / mo

$3,000

GPT-5.1

Per call

$0.00563

Per user / mo

$0.5625

Total / mo

$563

GPT-5.1 is cheaper by $2.4375/user/month — a saving of $2,438/month at 1,000 MAU.

Total monthly bill across MAU

Fable 5
GPT-5.1

Same usage profile applied to both models; only the per-token price differs.

Run this against your real numbers

The mini-calculator above is a preview. Use the full tools to model power-user blast radius, gross margin, and 12-month spend forecasts.

Other comparisons

DeepSeek V4 Pro vs GPT-5.1 Claude Sonnet 4.6 vs GPT-5.1 GPT-5.1 vs Claude Sonnet 4.5 Fable 5 vs GPT-5.5 Fable 5 vs Gemini 3.1 Pro Fable 5 vs Grok 4

Comparing Fable 5 vs GPT-5.1 on price alone never tells the whole story — output-token weighting, context length, and your usage profile change the answer dramatically. Use the calculators below for the full picture.