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Head-to-head comparison

GPT-6 Astra vs Grok 4.6

GPT-6 Astra (OpenAI) and Grok 4.6 (xAI) 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 9 September 2026

As of 9 September 2026, GPT-6 Astra holds the stronger ModelCap Index position (#1 vs #16); Grok 4.6 is 8.3× cheaper per output token ($6.00/1M vs $50.00/1M); and GPT-6 Astra offers the longer context window (1M vs 500K tokens).

Which should you choose?

Choose GPT-6 Astra if…

  • you want the stronger overall ModelCap Index position — #1 against #16 (93.7 vs 75.8 points).
  • you need the longer context window — 1M tokens against 500K.
  • LMArena Agent is your yardstick — 12.5% against 3.2%.
  • ARC-AGI-2 is your yardstick — 95.0% against 67.1%.
  • ARC-AGI-3 is your yardstick — 62.7% against 2.1%.
  • AA Intelligence Index is your yardstick — 52.8 against 44.4.
  • AA Humanity's Last Exam is your yardstick — 54.7% against 42.9%.
  • Terminal-Bench 4.0 is your yardstick — 58.2% against 20.3%.
  • you want the more recently listed model — GPT-6 Astra was listed 4 September 2026, Grok 4.6 12 August 2026.

Choose Grok 4.6 if…

  • API cost matters — $6.00/1M output tokens against $50.00/1M, about 8.3× cheaper.
  • your workload is prompt-heavy — input tokens cost $2.00/1M against $10.00/1M.

GPT-6 Astra vs Grok 4.6: specs, pricing and context

Specification comparison of GPT-6 Astra and Grok 4.6
FieldGPT-6 AstraOpenAIGrok 4.6xAI
ModelCap Index position#1#16
Index score93.775.8
EvidenceMeasuredMeasured
Input price / 1M tokens$10.00$2.00
Output price / 1M tokens$50.00$6.00
Context window1M tokens500K tokens
Max output tokens128K450K
API providers listed22
Weight accessAPI onlyAPI only
Input modalitiesFile, Image, TextText, Image, File
First listed4 September 202612 August 2026
PublisherOpenAIxAI

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

Benchmark scores: GPT-6 Astra vs Grok 4.6

Public benchmark boards where GPT-6 Astra or Grok 4.6 has a published result
BoardGPT-6 AstraGrok 4.6Leads
LMArena AgentLMArena12.5%10.4%–14.7%Max3.2%2.1%–4.4%X-HighGPT-6 Astra
ARC-AGI-2ARC Prize Foundation95.0%Max67.1%X-HighGPT-6 Astra
ARC-AGI-3ARC Prize Foundation62.7%Max2.1%X-HighGPT-6 Astra
AA Intelligence IndexArtificial Analysis52.8intelligence-index:v4.3:max44.4intelligence-index:v4.3:highGPT-6 Astra
AA Terminal-Bench 2.1Artificial Analysis88.4%terminal-bench:2.1:terminus-2:e2b:pass-at-1:3-repeats:source-model="GPT-6 Astra (max)":reasoning=true88.4%terminal-bench:2.1:terminus-2:e2b:pass-at-1:3-repeats:source-model="Grok 4.6 (high)":reasoning=trueTied
AA Humanity's Last ExamArtificial Analysis54.7%hle:may-2025:text-only-2158:no-tools:pass-at-1:source-model="GPT-6 Astra (max)":reasoning=true42.9%hle:may-2025:text-only-2158:no-tools:pass-at-1:source-model="Grok 4.6 (high)":reasoning=trueGPT-6 Astra
Terminal-Bench 4.0Terminal-Bench (Laude Institute)58.2%55.4%–61.0%Codex · Max20.3%17.2%–23.4%Grok Build · HighGPT-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 Grok 4.6: common questions

Is GPT-6 Astra better than Grok 4.6?

GPT-6 Astra ranks higher on the ModelCap Index as of 9 September 2026: #1 against #16. 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 Grok 4.6?

Grok 4.6 is cheaper on output tokens: $6.00/1M against $50.00/1M. Input tokens are $10.00/1M for GPT-6 Astra and $2.00/1M for Grok 4.6. 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 $7.00 for Grok 4.6. Grok 4.6 costs 84.4% 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 Grok 4.6?

GPT-6 Astra has the larger context window: 1M tokens against 500K.

Which is better for coding, GPT-6 Astra or Grok 4.6?

AA Terminal-Bench 2.1: GPT-6 Astra 88.4%, Grok 4.6 88.4% — tied. Terminal-Bench 4.0: GPT-6 Astra 58.2%, Grok 4.6 20.3% — GPT-6 Astra leads.

Are GPT-6 Astra and Grok 4.6 open-weight models?

GPT-6 Astra: API only. Grok 4.6: API only. Open weights mean the checkpoint can be downloaded and self-hosted under its licence; API-only models are available solely through hosted endpoints.

Where can I run GPT-6 Astra and Grok 4.6?

ModelCap currently lists 2 API providers for GPT-6 Astra and 2 for Grok 4.6, 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 Grok 4.6 comparison?

Every figure comes from the sealed ModelCap dataset published 9 September 2026; the page re-renders within a minute of each data refresh, and the ModelCap Index positions are the same ones shown on the live rankings.

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