ZMIME
Comparison · 2 models · Updated Oct 4, 2026

GPT-6.1 Sol vs GLM-5.3-Flash

GLM-5.3-Flash comes out ahead, 79 to 72 on our weighted score, and it is the cheaper option too.

  1. OpenAI

    GPT-6.1 Sol

    Released Sep 29, 2026

    72/100
    • ECI—
    • Price$2.00 / $10.00
    • Context1.05M
    Full specs Remove GPT-6.1 Sol
  2. Our pick

    Z.ai (Zhipu)

    GLM-5.3-Flash

    Released Aug 26, 2026

    79/100
    • ECI151.9
    • Price$0.15 / $0.50
    • Context1M
    Full specs Remove GLM-5.3-Flash

  3. Add a model

    Make it a three-way comparison.

01 — Verdict

GLM-5.3-Flash is our pick

GLM-5.3-Flash is the better all-round choice, scoring 79/100 against GPT-6.1 Sol (72). It leads on price and inputs & features. GPT-6.1 Sol wins on capability. The score weighs capability 50%, price 25%, inputs & features 15%, context window 10%. Capability uses the average of shared benchmarks (GPQA Diamond, FrontierMath Tiers 1–3 and OTIS Mock AIME 2024–2025), because GPT-6.1 Sol has no Capabilities Index score yet.

  • CapabilityGPT-6.1 SolShared benchmarks: GPT-6.1 Sol 96.4% · GLM-5.3-Flash 79.9%
  • Lowest priceGLM-5.3-FlashGLM-5.3-Flash $0.237 · GPT-6.1 Sol $4.00 per 1M tokens (3:1 blend)
  • Longest contextGPT-6.1 SolGPT-6.1 Sol 1,050,000 · GLM-5.3-Flash 1,000,000 tokens
  • Widest inputsGLM-5.3-FlashGPT-6.1 Sol: Text, Images, PDFs · GLM-5.3-Flash: Text, Images, PDFs, Video
  • Self-hostingGLM-5.3-FlashPublishes downloadable weights
How the score is built
MeasureWeightGPT-6.1 SolGLM-5.3-Flash
CapabilityShared benchmarks50%9680
Price25%2179
Inputs & features15%8090
Context window10%6160
Overall100%72/10079/100
02 — Side by side

Every spec in one table

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

GPT-6.1 Sol vs GLM-5.3-Flash specifications side by side
SpecificationGPT-6.1 SolOpenAIGLM-5.3-FlashZ.ai (Zhipu)
Capability
Capabilities Index (ECI)—151.9
ECI rank—#42 of 148
GPQA DiamondGraduate-level science questions95.4% (best)90.2%
FrontierMath Tiers 1–3Research-level mathematics93.7% (best)55.8%
OTIS Mock AIME 2024–2025Competition mathematics100% (best)93.9%
SimpleQA VerifiedShort factual questions73.9%—
Price per million tokens
Input$2.00$0.15 (best)
Output$10.00$0.50 (best)
Cached input$0.10$0.03 (best)
Blended (3:1)$4.00$0.237 (best)
Long-context rateOver 272K: $4.00 / $15.00Same rate
Price sourceOfficial OpenAI APIOfficial Z.AI API
Limits
Context window1,050,000 tokens (best)1,000,000 tokens
Max output128,000 tokens131,072 tokens (best)
Inputs and features
TextYesYes
ImagesYesYes
PDFsYesYes
AudioNoNo
VideoNoYes
ReasoningYeslow · medium · high · xhigh · maxYeslow · high · max
Tool callingYesYes
Structured outputYesYes
Availability
WeightsProprietaryOpen
API model IDgpt-6.1-solglm-5.3-flash
API providers2165 (best)
ReleasedSep 29, 2026Aug 26, 2026
Knowledge cutoffApr 30, 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.

  • GPT-6.1 Sol$40.00
  • GLM-5.3-Flash$2.50
04 — Questions

Which should you choose?

Which is better: GPT-6.1 Sol or GLM-5.3-Flash?

GLM-5.3-Flash is the better all-round choice, scoring 79/100 against GPT-6.1 Sol (72). It leads on price and inputs & features. GPT-6.1 Sol wins on capability. The score weighs capability 50%, price 25%, inputs & features 15%, context window 10%. Capability uses the average of shared benchmarks (GPQA Diamond, FrontierMath Tiers 1–3 and OTIS Mock AIME 2024–2025), because GPT-6.1 Sol has no Capabilities Index score yet.

Which is cheaper, GPT-6.1 Sol or GLM-5.3-Flash?

GLM-5.3-Flash is cheaper at $0.15 input / $0.50 output per million tokens (official Z.AI API price). GPT-6.1 Sol costs $2.00 input / $10.00 output per million tokens (official OpenAI API price). At a typical mix of three input tokens to one output token, that is $0.237 per million tokens for GLM-5.3-Flash versus $4.00 for GPT-6.1 Sol (17× as much).

Which scores higher on benchmarks?

Not every model here has a Capabilities Index score, so we compare the average of shared benchmarks (GPQA Diamond, FrontierMath Tiers 1–3 and OTIS Mock AIME 2024–2025): GPT-6.1 Sol 96.4% and GLM-5.3-Flash 79.9%. On individual benchmarks: GPQA Diamond — GPT-6.1 Sol 95.4%, GLM-5.3-Flash 90.2%; FrontierMath Tiers 1–3 — GPT-6.1 Sol 93.7%, GLM-5.3-Flash 55.8%; OTIS Mock AIME 2024–2025 — GPT-6.1 Sol 100%, GLM-5.3-Flash 93.9%.

Which is better for coding?

There are no published SWE-bench Verified results for GPT-6.1 Sol and GLM-5.3-Flash yet, so there is no like-for-like coding score. On overall capability, GPT-6.1 Sol 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?

GPT-6.1 Sol has the largest context window at 1,050,000 tokens, against 1,000,000 for GLM-5.3-Flash. Maximum output per response: GPT-6.1 Sol up to 128,000, GLM-5.3-Flash up to 131,072 tokens.

Which can read images, PDFs, audio or video?

GPT-6.1 Sol accepts text, images and PDFs; GLM-5.3-Flash accepts text, images, PDFs and video. GLM-5.3-Flash handles the widest range of inputs.

Are any of these open source?

GLM-5.3-Flash publishes its weights and can be self-hosted; GPT-6.1 Sol is proprietary.

Which is newer?

GPT-6.1 Sol is the newest, released Sep 29, 2026. GLM-5.3-Flash came out Aug 26, 2026. Knowledge cutoff: GPT-6.1 Sol Apr 30, 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 Oct 4, 2026.

05 — Keep comparing

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