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Head-to-head comparison

GPT-6 Astra vs GLM 5.3 Flash

GPT-6 Astra (OpenAI) and GLM 5.3 Flash (Z.ai) compared on the ModelCap Index, API price, context window, provider availability, weight access and every public benchmark board they share. Figures are the same ones shown on the live rankings; nothing here is a hidden score.

Snapshot as of 24 October 2026

As of 24 October 2026, GPT-6 Astra holds the stronger ModelCap Index position (#13 vs #24); GLM 5.3 Flash is 100× cheaper per output token ($0.50/1M vs $50.00/1M); and GLM 5.3 Flash ships open weights.

Which should you choose?

Choose GPT-6 Astra if…

  • you want the stronger overall ModelCap Index position — #13 against #24 (79.9 vs 77.3 points).
  • Arena text is your yardstick — 1476 against 1476.
  • Arena coding is your yardstick — 1543 against 1525.
  • LMArena Agent is your yardstick — 14.0% against -1.8%.
  • ARC-AGI-2 is your yardstick — 95.0% against 65.8%.
  • AA Intelligence Index is your yardstick — 52.7 against 41.8.
  • AA Terminal-Bench 2.1 is your yardstick — 88.4% against 84.3%.
  • AA Humanity's Last Exam is your yardstick — 54.7% against 39.9%.
  • Terminal-Bench 4.0 is your yardstick — 58.2% against 35.8%.
  • you want the more recently listed model — GPT-6 Astra was listed 4 September 2026, GLM 5.3 Flash 26 August 2026.

Choose GLM 5.3 Flash if…

  • API cost matters — $0.50/1M output tokens against $50.00/1M, about 100× cheaper.
  • your workload is prompt-heavy — input tokens cost $0.15/1M against $10.00/1M.
  • you want to self-host: GLM 5.3 Flash ships open weights while GPT-6 Astra is no linked weights.
  • you want provider choice — 34 listed API providers against 3.

GPT-6 Astra vs GLM 5.3 Flash: specs, pricing and context

Specification comparison of GPT-6 Astra and GLM 5.3 Flash
FieldGPT-6 AstraOpenAIGLM 5.3 FlashZ.ai
ModelCap Index position#13#24
Index score79.977.3
EvidenceMeasuredMeasured
Input price / 1M tokens$10.00$0.15
Output price / 1M tokens$50.00$0.50
Context window1M tokens1M tokens
Declared route output cap128K944K
API providers listed334
Weight accessNo linked weightsOpen weights
Input modalitiesFile, Image, TextText, Image, Video
First listed4 September 202626 August 2026
PublisherOpenAIZ.ai

Evidence: 5 public benchmark observations across 5 boards · 4 public benchmark observations across 4 boards. Prices are the lowest listed API offer per million tokens observed on the OpenRouter catalogue.

Benchmark scores: GPT-6 Astra vs GLM 5.3 Flash

Public benchmark boards where GPT-6 Astra or GLM 5.3 Flash has a published result
BoardGPT-6 AstraGLM 5.3 FlashLeads
Arena textArena (LMArena)14761470–1483Max14761471–1481Not reportedGPT-6 Astra
Arena codingArena (LMArena)15431532–1554Max15251518–1532GPT-6 Astra
LMArena AgentLMArena14.0%11.9%–16.0%Max-1.8%-2.4%–-1.1%GPT-6 Astra
ARC-AGI-2ARC Prize Foundation95.0%Max65.8%MaxGPT-6 Astra
ARC-AGI-3ARC Prize Foundation62.7%Max—Only one result
AA Intelligence IndexArtificial Analysis52.7Max41.8ReasoningGPT-6 Astra
AA Terminal-Bench 2.1Artificial Analysis88.4%Max84.3%ReasoningGPT-6 Astra
AA Humanity's Last ExamArtificial Analysis54.7%Max39.9%ReasoningGPT-6 Astra
Terminal-Bench 4.0Terminal-Bench (Laude Institute)58.2%55.4%–61.0%Codex · Max35.8%32.2%–39.3%Claude Code · NoneGPT-6 Astra

Scores are the sources' own published figures for each model's best evaluated configuration; ModelCap never re-runs a benchmark.

Want a different pairing? Open the interactive comparison tool to swap either model for any current ranked language model.

GPT-6 Astra vs GLM 5.3 Flash: common questions

Is GPT-6 Astra better than GLM 5.3 Flash?

GPT-6 Astra ranks higher on the ModelCap Index as of 24 October 2026: #13 against #24. That is a capability ranking built from public benchmark evidence with published uncertainty; whether it is "better" for you also depends on price, context and where you can run it. Their published uncertainty intervals overlap, so the rank difference alone does not establish a reliable capability advantage for your workload.

Is GPT-6 Astra cheaper than GLM 5.3 Flash?

GLM 5.3 Flash is cheaper on output tokens: $0.50/1M against $50.00/1M. Input tokens are $10.00/1M for GPT-6 Astra and $0.15/1M for GLM 5.3 Flash. Prices are the lowest listed API offer ModelCap observed, in USD per million tokens. For 1,000 requests with 2,000 input and 500 output tokens each (2M input + 0.5M output), the listed-rate estimate is $45.00 for GPT-6 Astra versus $0.55 for GLM 5.3 Flash. GLM 5.3 Flash costs 98.8% less in this scenario. This excludes caching, batch discounts, prompt-length tiers, tool charges and retries; verify the selected endpoint before budgeting.

Which has the bigger context window, GPT-6 Astra or GLM 5.3 Flash?

Both publish a 1M-token context window. OpenRouter catalogue or provider-endpoint declaration. Limits can vary by provider and prompt length; a model-wide maximum has not been independently verified.

Which is better for coding, GPT-6 Astra or GLM 5.3 Flash?

Arena coding: GPT-6 Astra 1543, GLM 5.3 Flash 1525 — GPT-6 Astra leads. AA Terminal-Bench 2.1: GPT-6 Astra 88.4%, GLM 5.3 Flash 84.3% — GPT-6 Astra leads. Terminal-Bench 4.0: GPT-6 Astra 58.2%, GLM 5.3 Flash 35.8% — GPT-6 Astra leads.

Are GPT-6 Astra and GLM 5.3 Flash open-weight models?

GPT-6 Astra: No linked weights. GLM 5.3 Flash: Open weights. Open weights mean the checkpoint can be downloaded and self-hosted under its licence. A missing weight link does not identify every API or chat product that offers a model.

Where can I run GPT-6 Astra and GLM 5.3 Flash?

ModelCap currently lists 3 API providers for GPT-6 Astra and 34 for GLM 5.3 Flash, from the OpenRouter catalogue snapshot the site serves; each model page lists the providers and their prices.

How current is this GPT-6 Astra vs GLM 5.3 Flash comparison?

Every figure and ModelCap Index position comes from the same published snapshot dated 24 October 2026. Publication and page updates happen separately; use the snapshot date shown on the page.

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