ZMIME
Comparison · 2 models · Updated Nov 2, 2026

Claude Sonnet 5.5 vs GLM-5.3

Claude Sonnet 5.5 comes out ahead, 72 to 63 on our weighted score, though GLM-5.3 is 46% cheaper per token.

  1. Our pick

    Anthropic

    Claude Sonnet 5.5

    Released Sep 28, 2026New

    72/100
    • ECI166.7
    • Price$2.00 / $10.00
    • Context1M
    Full specs Remove Claude Sonnet 5.5

  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 Sonnet 5.5 is our pick

Claude Sonnet 5.5 is the better all-round choice, scoring 72/100 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 Sonnet 5.5Capabilities Index (ECI): Claude Sonnet 5.5 166.7 · GLM-5.3 156.2
  • Lowest priceGLM-5.3GLM-5.3 $2.15 · Claude Sonnet 5.5 $4.00 per 1M tokens (3:1 blend)
  • Longest contextAbout the sameClaude Sonnet 5.5 1,000,000 · GLM-5.3 1,000,000 tokens
  • Widest inputsClaude Sonnet 5.5Claude Sonnet 5.5: Text, Images, PDFs · GLM-5.3: Text
  • Self-hostingGLM-5.3Publishes downloadable weights
How the score is built
MeasureWeightClaude Sonnet 5.5GLM-5.3
CapabilityCapabilities Index (ECI)50%9784
Price25%2033
Inputs & features15%8045
Context window10%6060
Overall100%72/10063/100
02 — Side by side

Every spec in one table

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

Claude Sonnet 5.5 vs GLM-5.3 specifications side by side
SpecificationClaude Sonnet 5.5AnthropicGLM-5.3Z.ai (Zhipu)
Capability
Capabilities Index (ECI)166.7 (best)156.2
ECI rank#5 of 165 (best)#33 of 165
GPQA DiamondGraduate-level science questions95.6% (best)90.9%
FrontierMath Tiers 1–3Research-level mathematics88.8% (best)68.8%
OTIS Mock AIME 2024–2025Competition mathematics100% (best)91.1%
SimpleQA VerifiedShort factual questions46.5% (best)41.0%
Price per million tokens
Input$2.00$1.40 (best)
Output$10.00$4.40 (best)
Cached input$0.10 (best)$0.26
Blended (3:1)$4.00$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-sonnet-5-5glm-5.3
API providers3483 (best)
ReleasedSep 28, 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 Sonnet 5.5$40.00
  • GLM-5.3$22.80
04 — Questions

Which should you choose?

Which is better: Claude Sonnet 5.5 or GLM-5.3?

Claude Sonnet 5.5 is the better all-round choice, scoring 72/100 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 Sonnet 5.5 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 Sonnet 5.5 costs $2.00 input / $10.00 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 $4.00 for Claude Sonnet 5.5 (1.9× as much).

Which scores higher on benchmarks?

Claude Sonnet 5.5 scores higher on the Capabilities Index (ECI): Claude Sonnet 5.5 166.7 (#5 of 165) and GLM-5.3 156.2 (#33 of 165). Their confidence ranges do not overlap (163.6–171.3 vs 154.3–158.5), so the gap is a real one. On individual benchmarks: GPQA Diamond — Claude Sonnet 5.5 95.6%, GLM-5.3 90.9%; FrontierMath Tiers 1–3 — Claude Sonnet 5.5 88.8%, GLM-5.3 68.8%; OTIS Mock AIME 2024–2025 — Claude Sonnet 5.5 100%, GLM-5.3 91.1%; SimpleQA Verified — Claude Sonnet 5.5 46.5%, GLM-5.3 41.0%.

Which is better for coding?

There are no published SWE-bench Verified results for Claude Sonnet 5.5 and GLM-5.3 yet, so there is no like-for-like coding score. On overall capability, Claude Sonnet 5.5 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 Sonnet 5.5 and GLM-5.3 share the same 1,000,000-token context window. Maximum output per response: Claude Sonnet 5.5 up to 128,000, GLM-5.3 up to 131,072 tokens.

Which can read images, PDFs, audio or video?

Claude Sonnet 5.5 accepts text, images and PDFs; GLM-5.3 accepts text. Claude Sonnet 5.5 handles the widest range of inputs.

Are any of these open source?

GLM-5.3 publishes its weights and can be self-hosted; Claude Sonnet 5.5 is proprietary.

Which is newer?

Claude Sonnet 5.5 is the newest, released Sep 28, 2026. GLM-5.3 came out Aug 14, 2026. Knowledge cutoff: Claude Sonnet 5.5 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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