ZMIME
Comparison · 2 models · Updated Nov 2, 2026

Claude Fable 5.1 vs GLM-5.3

Claude Fable 5.1 comes out ahead, 66 to 63 on our weighted score, though GLM-5.3 is 9.3× cheaper per token.

  1. Our pick

    Anthropic

    Claude Fable 5.1

    Released Sep 1, 2026

    66/100
    • ECI166.4
    • Price$10.00 / $50.00
    • Context1M
    Full specs Remove Claude Fable 5.1

  2. Z.ai (Zhipu)

    GLM-5.3

    Released Aug 14, 2026

    63/100
    • ECI156.2
    • Price$1.40 / $4.40
    • Context1M
    Full specs Remove GLM-5.3

  3. Add a model

    Make it a three-way comparison.

01 — Verdict

Claude Fable 5.1 is our pick

Claude Fable 5.1 is the better all-round choice, scoring 66/100 against GLM-5.3 (63). It leads on capability and inputs & features. GLM-5.3 wins on price. The score weighs capability 50%, price 25%, inputs & features 15%, context window 10%.

  • CapabilityClaude Fable 5.1Capabilities Index (ECI): Claude Fable 5.1 166.4 · GLM-5.3 156.2
  • Lowest priceGLM-5.3GLM-5.3 $2.15 · Claude Fable 5.1 $20.00 per 1M tokens (3:1 blend)
  • Longest contextAbout the sameClaude Fable 5.1 1,000,000 · GLM-5.3 1,000,000 tokens
  • Widest inputsClaude Fable 5.1Claude Fable 5.1: Text, Images, PDFs · GLM-5.3: Text
  • Self-hostingGLM-5.3Publishes downloadable weights
How the score is built
MeasureWeightClaude Fable 5.1GLM-5.3
CapabilityCapabilities Index (ECI)50%9784
Price25%033
Inputs & features15%8045
Context window10%6060
Overall100%66/10063/100
02 — Side by side

Every spec in one table

Highlighted cells lead their row. Dashes mean the data is not published.

Claude Fable 5.1 vs GLM-5.3 specifications side by side
SpecificationClaude Fable 5.1AnthropicGLM-5.3Z.ai (Zhipu)
Capability
Capabilities Index (ECI)166.4 (best)156.2
ECI rank#6 of 165 (best)#33 of 165
GPQA DiamondGraduate-level science questions—90.9%
FrontierMath Tiers 1–3Research-level mathematics90.2% (best)68.8%
OTIS Mock AIME 2024–2025Competition mathematics100% (best)91.1%
SimpleQA VerifiedShort factual questions70.8% (best)41.0%
Price per million tokens
Input$10.00$1.40 (best)
Output$50.00$4.40 (best)
Cached input$0.25 (best)$0.26
Blended (3:1)$20.00$2.15 (best)
Long-context rateSame rateSame rate
Price sourceOfficial Anthropic APIOfficial Z.AI API
Limits
Context window1,000,000 tokens1,000,000 tokens
Max output128,000 tokens131,072 tokens (best)
Inputs and features
TextYesYes
ImagesYesNo
PDFsYesNo
AudioNoNo
VideoNoNo
ReasoningYeslow · medium · high · xhigh · maxYeslow · high · max
Tool callingYesYes
Structured outputYesYes
Availability
WeightsProprietaryOpen
API model IDclaude-fable-5-1glm-5.3
API providers3783 (best)
ReleasedSep 1, 2026Aug 14, 2026
Knowledge cutoffJun 2026—
03 — Cost

What would a month cost?

Enter your expected volume in millions of tokens. List prices only; caching and batch discounts would lower these.

  • Claude Fable 5.1$200.00
  • GLM-5.3$22.80
04 — Questions

Which should you choose?

Which is better: Claude Fable 5.1 or GLM-5.3?

Claude Fable 5.1 is the better all-round choice, scoring 66/100 against GLM-5.3 (63). It leads on capability and inputs & features. GLM-5.3 wins on price. The score weighs capability 50%, price 25%, inputs & features 15%, context window 10%.

Which is cheaper, Claude Fable 5.1 or GLM-5.3?

GLM-5.3 is cheaper at $1.40 input / $4.40 output per million tokens (official Z.AI API price). Claude Fable 5.1 costs $10.00 input / $50.00 output per million tokens (official Anthropic API price). At a typical mix of three input tokens to one output token, that is $2.15 per million tokens for GLM-5.3 versus $20.00 for Claude Fable 5.1 (9.3× as much).

Which scores higher on benchmarks?

Claude Fable 5.1 scores higher on the Capabilities Index (ECI): Claude Fable 5.1 166.4 (#6 of 165) and GLM-5.3 156.2 (#33 of 165). Their confidence ranges do not overlap (163.6–170.8 vs 154.3–158.5), so the gap is a real one. On individual benchmarks: FrontierMath Tiers 1–3 — Claude Fable 5.1 90.2%, GLM-5.3 68.8%; OTIS Mock AIME 2024–2025 — Claude Fable 5.1 100%, GLM-5.3 91.1%; SimpleQA Verified — Claude Fable 5.1 70.8%, GLM-5.3 41.0%.

Which is better for coding?

There are no published SWE-bench Verified results for Claude Fable 5.1 and GLM-5.3 yet, so there is no like-for-like coding score. On overall capability, Claude Fable 5.1 leads, which tends to carry over to coding, but test on your own codebase. Both support tool calling for agent workflows.

Which has the bigger context window?

Claude Fable 5.1 and GLM-5.3 share the same 1,000,000-token context window. Maximum output per response: Claude Fable 5.1 up to 128,000, GLM-5.3 up to 131,072 tokens.

Which can read images, PDFs, audio or video?

Claude Fable 5.1 accepts text, images and PDFs; GLM-5.3 accepts text. Claude Fable 5.1 handles the widest range of inputs.

Are any of these open source?

GLM-5.3 publishes its weights and can be self-hosted; Claude Fable 5.1 is proprietary.

Which is newer?

Claude Fable 5.1 is the newest, released Sep 1, 2026. GLM-5.3 came out Aug 14, 2026. Knowledge cutoff: Claude Fable 5.1 Jun 2026.

How do you decide the winner?

Each model gets a 0–100 score on capability (50%, independent benchmark results); price (25%, blended price per million tokens (3 input : 1 output), log scale); inputs & features (15%, image, PDF, audio and video input, tool calling, structured output and reasoning); context window (10%, maximum tokens per request, log scale). Dimensions missing for any model are dropped and the remaining weights rescaled, so every model is judged on the same evidence. Specs and prices come from public model listings and the labs’ own API pages; capability scores come from independent benchmark runs. Data updated Nov 2, 2026.

05 — Keep comparing

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