ZMIME
Comparison · 2 models · Updated Nov 2, 2026

Claude Opus 5.5 vs GLM-5.3

Claude Opus 5.5 comes out ahead, 69 to 63 on our weighted score, though GLM-5.3 is 3.7× cheaper per token.

  1. Our pick

    Anthropic

    Claude Opus 5.5

    Released Sep 22, 2026New

    69/100
    • ECI168.4
    • Price$4.00 / $20.00
    • Context1M
    Full specs Remove Claude Opus 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 Opus 5.5 is our pick

Claude Opus 5.5 is the better all-round choice, scoring 69/100 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 Opus 5.5Capabilities Index (ECI): Claude Opus 5.5 168.4 · GLM-5.3 156.2
  • Lowest priceGLM-5.3GLM-5.3 $2.15 · Claude Opus 5.5 $8.00 per 1M tokens (3:1 blend)
  • Longest contextAbout the sameClaude Opus 5.5 1,000,000 · GLM-5.3 1,000,000 tokens
  • Widest inputsClaude Opus 5.5Claude Opus 5.5: Text, Images, PDFs · GLM-5.3: Text
  • Self-hostingGLM-5.3Publishes downloadable weights
How the score is built
MeasureWeightClaude Opus 5.5GLM-5.3
CapabilityCapabilities Index (ECI)50%9984
Price25%733
Inputs & features15%8045
Context window10%6060
Overall100%69/10063/100
02 — Side by side

Every spec in one table

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

Claude Opus 5.5 vs GLM-5.3 specifications side by side
SpecificationClaude Opus 5.5AnthropicGLM-5.3Z.ai (Zhipu)
Capability
Capabilities Index (ECI)168.4 (best)156.2
ECI rank#2 of 165 (best)#33 of 165
GPQA DiamondGraduate-level science questions90.6%90.9% (best)
FrontierMath Tiers 1–3Research-level mathematics91.2% (best)68.8%
OTIS Mock AIME 2024–2025Competition mathematics100% (best)91.1%
SimpleQA VerifiedShort factual questions72.2% (best)41.0%
Price per million tokens
Input$4.00$1.40 (best)
Output$20.00$4.40 (best)
Cached input$0.20 (best)$0.26
Blended (3:1)$8.00$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-opus-5-5glm-5.3
API providers3683 (best)
ReleasedSep 22, 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 Opus 5.5$80.00
  • GLM-5.3$22.80
04 — Questions

Which should you choose?

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

Claude Opus 5.5 is the better all-round choice, scoring 69/100 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 Opus 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 Opus 5.5 costs $4.00 input / $20.00 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 $8.00 for Claude Opus 5.5 (3.7× as much).

Which scores higher on benchmarks?

Claude Opus 5.5 scores higher on the Capabilities Index (ECI): Claude Opus 5.5 168.4 (#2 of 165) and GLM-5.3 156.2 (#33 of 165). Their confidence ranges do not overlap (165.4–173.0 vs 154.3–158.5), so the gap is a real one. On individual benchmarks: GPQA Diamond — GLM-5.3 90.9%, Claude Opus 5.5 90.6%; FrontierMath Tiers 1–3 — Claude Opus 5.5 91.2%, GLM-5.3 68.8%; OTIS Mock AIME 2024–2025 — Claude Opus 5.5 100%, GLM-5.3 91.1%; SimpleQA Verified — Claude Opus 5.5 72.2%, GLM-5.3 41.0%.

Which is better for coding?

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

Which can read images, PDFs, audio or video?

Claude Opus 5.5 accepts text, images and PDFs; GLM-5.3 accepts text. Claude Opus 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 Opus 5.5 is proprietary.

Which is newer?

Claude Opus 5.5 is the newest, released Sep 22, 2026. GLM-5.3 came out Aug 14, 2026. Knowledge cutoff: Claude Opus 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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