ZMIME
Comparison · 2 models · Updated Oct 4, 2026

GLM-5.1 vs Gemini Robotics-ER 1.6 Preview

Gemini Robotics-ER 1.6 Preview comes out ahead, 50 to 37 on our weighted score, and it is the cheaper option too.

  1. Z.ai (Zhipu)

    GLM-5.1

    Released Apr 7, 2026

    37/100
    • ECI149.9
    • Price$1.40 / $4.40
    • Context200K
    Full specs Remove GLM-5.1
  2. Our pick

    Google

    Gemini Robotics-ER 1.6 Preview

    Released Apr 14, 2026

    50/100
    • ECI—
    • Price$1.00 / $5.00
    • Context131K
    Full specs Remove Gemini Robotics-ER 1.6 Preview

  3. Add a model

    Make it a three-way comparison.

01 — Verdict

Gemini Robotics-ER 1.6 Preview is our pick

Gemini Robotics-ER 1.6 Preview is the better all-round choice, scoring 50/100 against GLM-5.1 (37). It leads on inputs & features. GLM-5.1 wins on context window. The score weighs price 50%, inputs & features 30%, context window 20%. None of the shared benchmarks cover every model here yet, so capability is left out of this verdict.

  • CapabilityNot enough dataNo independent benchmark covers every model here yet
  • Lowest priceGemini Robotics-ER 1.6 PreviewGemini Robotics-ER 1.6 Preview $2.00 · GLM-5.1 $2.15 per 1M tokens (3:1 blend)
  • Longest contextGLM-5.1GLM-5.1 200,000 · Gemini Robotics-ER 1.6 Preview 131,072 tokens
  • Widest inputsGemini Robotics-ER 1.6 PreviewGLM-5.1: Text · Gemini Robotics-ER 1.6 Preview: Text, Images, Audio, Video
  • Self-hostingGLM-5.1Publishes downloadable weights
How the score is built
MeasureWeightGLM-5.1Gemini Robotics-ER 1.6 Preview
Price50%3436
Inputs & features30%4590
Context window20%3224
Overall100%37/10050/100

Left out because at least one model lacks the data: capability. The remaining weights were rescaled.

02 — Side by side

Every spec in one table

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

GLM-5.1 vs Gemini Robotics-ER 1.6 Preview specifications side by side
SpecificationGLM-5.1Z.ai (Zhipu)Gemini Robotics-ER 1.6 PreviewGoogle
Capability
Capabilities Index (ECI)149.9—
ECI rank#51 of 148—
GPQA DiamondGraduate-level science questions89.9%—
FrontierMath Tiers 1–3Research-level mathematics36.8%—
OTIS Mock AIME 2024–2025Competition mathematics93.3%—
SWE-bench VerifiedFixing real GitHub issues74.2%—
SimpleQA VerifiedShort factual questions34.0%—
Price per million tokens
Input$1.40$1.00 (best)
Output$4.40 (best)$5.00
Cached input$0.26—
Blended (3:1)$2.15$2.00 (best)
Long-context rateSame rateSame rate
Price sourceOfficial Z.AI APIMedian of 1 providers
Limits
Context window200,000 tokens (best)131,072 tokens
Max output131,072 tokens (best)65,536 tokens
Inputs and features
TextYesYes
ImagesNoYes
PDFsNoNo
AudioNoYes
VideoNoYes
ReasoningYesYes
Tool callingYesYes
Structured outputYesYes
Availability
WeightsOpenProprietary
API model IDglm-5.1—
API providers40 (best)1
ReleasedApr 7, 2026Apr 14, 2026
Knowledge cutoff—Jan 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.

  • GLM-5.1$22.80
  • Gemini Robotics-ER 1.6 Preview$20.00
04 — Questions

Which should you choose?

Which is better: GLM-5.1 or Gemini Robotics-ER 1.6 Preview?

Gemini Robotics-ER 1.6 Preview is the better all-round choice, scoring 50/100 against GLM-5.1 (37). It leads on inputs & features. GLM-5.1 wins on context window. The score weighs price 50%, inputs & features 30%, context window 20%. None of the shared benchmarks cover every model here yet, so capability is left out of this verdict.

Which is cheaper, GLM-5.1 or Gemini Robotics-ER 1.6 Preview?

Gemini Robotics-ER 1.6 Preview is cheaper at $1.00 input / $5.00 output per million tokens (median across 1 API provider). GLM-5.1 costs $1.40 input / $4.40 output per million tokens (official Z.AI API price). At a typical mix of three input tokens to one output token, that is $2.00 per million tokens for Gemini Robotics-ER 1.6 Preview versus $2.15 for GLM-5.1 (1.1× as much).

Which scores higher on benchmarks?

There is no independent benchmark that covers both models yet. GLM-5.1 has an ECI of 149.9 and Gemini Robotics-ER 1.6 Preview has not been scored yet.

Which is better for coding?

There are no published SWE-bench Verified results for Gemini Robotics-ER 1.6 Preview yet, so there is no like-for-like coding score. Test both on a sample of your own tasks. Both support tool calling for agent workflows.

Which has the bigger context window?

GLM-5.1 has the largest context window at 200,000 tokens, against 131,072 for Gemini Robotics-ER 1.6 Preview. Maximum output per response: GLM-5.1 up to 131,072, Gemini Robotics-ER 1.6 Preview up to 65,536 tokens.

Which can read images, PDFs, audio or video?

GLM-5.1 accepts text; Gemini Robotics-ER 1.6 Preview accepts text, images, audio and video. Gemini Robotics-ER 1.6 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 Robotics-ER 1.6 Preview is proprietary.

Which is newer?

Gemini Robotics-ER 1.6 Preview is the newest, released Apr 14, 2026. GLM-5.1 came out Apr 7, 2026. Knowledge cutoff: Gemini Robotics-ER 1.6 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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