ZMIME
Comparison · 2 models · Updated Oct 4, 2026

Gemini 3.1 Pro Preview vs GLM-5.1

Gemini 3.1 Pro Preview comes out ahead, 68 to 57 on our weighted score, though GLM-5.1 is 2.1× cheaper per token.

  1. Our pick

    Google

    Gemini 3.1 Pro Preview

    Released Feb 19, 2026

    68/100
    • ECI154.8
    • Price$2.00 / $12.00
    • Context1.05M
    Full specs Remove Gemini 3.1 Pro Preview

  2. Z.ai (Zhipu)

    GLM-5.1

    Released Apr 7, 2026

    57/100
    • ECI149.9
    • Price$1.40 / $4.40
    • Context200K
    Full specs Remove GLM-5.1

  3. Add a model

    Make it a three-way comparison.

01 — Verdict

Gemini 3.1 Pro Preview is our pick

Gemini 3.1 Pro Preview is the better all-round choice, scoring 68/100 against GLM-5.1 (57). It leads on capability, inputs & features and context window. GLM-5.1 wins on price. The score weighs capability 50%, price 25%, inputs & features 15%, context window 10%.

  • CapabilityGemini 3.1 Pro PreviewCapabilities Index (ECI): Gemini 3.1 Pro Preview 154.8 · GLM-5.1 149.9
  • Lowest priceGLM-5.1GLM-5.1 $2.15 · Gemini 3.1 Pro Preview $4.50 per 1M tokens (3:1 blend)
  • Longest contextGemini 3.1 Pro PreviewGemini 3.1 Pro Preview 1,048,576 · GLM-5.1 200,000 tokens
  • Widest inputsGemini 3.1 Pro PreviewGemini 3.1 Pro Preview: Text, Images, PDFs, Audio, Video · GLM-5.1: Text
  • Self-hostingGLM-5.1Publishes downloadable weights
How the score is built
MeasureWeightGemini 3.1 Pro PreviewGLM-5.1
CapabilityCapabilities Index (ECI)50%8478
Price25%1934
Inputs & features15%10045
Context window10%6132
Overall100%68/10057/100
02 — Side by side

Every spec in one table

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

Gemini 3.1 Pro Preview vs GLM-5.1 specifications side by side
SpecificationGemini 3.1 Pro PreviewGoogleGLM-5.1Z.ai (Zhipu)
Capability
Capabilities Index (ECI)154.8 (best)149.9
ECI rank#31 of 148 (best)#51 of 148
GPQA DiamondGraduate-level science questions94.4% (best)89.9%
FrontierMath Tiers 1–3Research-level mathematics59.7% (best)36.8%
OTIS Mock AIME 2024–2025Competition mathematics95.6% (best)93.3%
SWE-bench VerifiedFixing real GitHub issues75.6% (best)74.2%
SimpleQA VerifiedShort factual questions73.5% (best)34.0%
Price per million tokens
Input$2.00$1.40 (best)
Output$12.00$4.40 (best)
Cached input$0.20 (best)$0.26
Blended (3:1)$4.50$2.15 (best)
Long-context rateOver 200K: $4.00 / $18.00Same rate
Price sourceOfficial Google APIOfficial Z.AI API
Limits
Context window1,048,576 tokens (best)200,000 tokens
Max output65,536 tokens131,072 tokens (best)
Inputs and features
TextYesYes
ImagesYesNo
PDFsYesNo
AudioYesNo
VideoYesNo
ReasoningYeslow · medium · highYes
Tool callingYesYes
Structured outputYesYes
Availability
WeightsProprietaryOpen
API model IDgemini-3.1-pro-previewglm-5.1
API providers2640 (best)
ReleasedFeb 19, 2026Apr 7, 2026
Knowledge cutoffJan 2025—
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.

  • Gemini 3.1 Pro Preview$44.00
  • GLM-5.1$22.80
04 — Questions

Which should you choose?

Which is better: Gemini 3.1 Pro Preview or GLM-5.1?

Gemini 3.1 Pro Preview is the better all-round choice, scoring 68/100 against GLM-5.1 (57). It leads on capability, inputs & features and context window. GLM-5.1 wins on price. The score weighs capability 50%, price 25%, inputs & features 15%, context window 10%.

Which is cheaper, Gemini 3.1 Pro Preview or GLM-5.1?

GLM-5.1 is cheaper at $1.40 input / $4.40 output per million tokens (official Z.AI API price). Gemini 3.1 Pro Preview costs $2.00 input / $12.00 output per million tokens (official Google API price). At a typical mix of three input tokens to one output token, that is $2.15 per million tokens for GLM-5.1 versus $4.50 for Gemini 3.1 Pro Preview (2.1× as much).

Which scores higher on benchmarks?

Gemini 3.1 Pro Preview scores higher on the Capabilities Index (ECI): Gemini 3.1 Pro Preview 154.8 (#31 of 148) and GLM-5.1 149.9 (#51 of 148). Their confidence ranges do not overlap (152.6–157.3 vs 148.0–151.6), so the gap is a real one. On individual benchmarks: GPQA Diamond — Gemini 3.1 Pro Preview 94.4%, GLM-5.1 89.9%; FrontierMath Tiers 1–3 — Gemini 3.1 Pro Preview 59.7%, GLM-5.1 36.8%; OTIS Mock AIME 2024–2025 — Gemini 3.1 Pro Preview 95.6%, GLM-5.1 93.3%; SWE-bench Verified — Gemini 3.1 Pro Preview 75.6%, GLM-5.1 74.2%; SimpleQA Verified — Gemini 3.1 Pro Preview 73.5%, GLM-5.1 34.0%.

Which is better for coding?

Gemini 3.1 Pro Preview resolves more real GitHub issues on SWE-bench Verified: Gemini 3.1 Pro Preview 75.6% and GLM-5.1 74.2%. Both support tool calling for agent workflows.

Which has the bigger context window?

Gemini 3.1 Pro Preview has the largest context window at 1,048,576 tokens, against 200,000 for GLM-5.1. Maximum output per response: Gemini 3.1 Pro Preview up to 65,536, GLM-5.1 up to 131,072 tokens.

Which can read images, PDFs, audio or video?

Gemini 3.1 Pro Preview accepts text, images, PDFs, audio and video; GLM-5.1 accepts text. Gemini 3.1 Pro Preview handles the widest range of inputs.

Are any of these open source?

GLM-5.1 publishes its weights and can be self-hosted; Gemini 3.1 Pro Preview is proprietary.

Which is newer?

GLM-5.1 is the newest, released Apr 7, 2026. Gemini 3.1 Pro Preview came out Feb 19, 2026. Knowledge cutoff: Gemini 3.1 Pro Preview Jan 2025.

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 Oct 4, 2026.

05 — Keep comparing

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