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Head-to-head comparison

GPT-6 Astra vs o3

GPT-6 Astra (OpenAI) and o3 (OpenAI) 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 #46); o3 is 6.3× cheaper per output token ($8.00/1M vs $50.00/1M); and GPT-6 Astra offers the longer context window (1M vs 200K tokens).

Which should you choose?

Choose GPT-6 Astra if…

  • you want the stronger overall ModelCap Index position — #1 against #46 (93.7 vs 61.0 points).
  • you need the longer context window — 1M tokens against 200K.
  • you want provider choice — 2 listed API providers against 1.
  • ARC-AGI-2 is your yardstick — 95.0% against 6.5%.
  • AA Humanity's Last Exam is your yardstick — 54.7% against 20.1%.
  • you want the more recently listed model — GPT-6 Astra was listed 4 September 2026, o3 16 April 2025.

Choose o3 if…

  • API cost matters — $8.00/1M output tokens against $50.00/1M, about 6.3× cheaper.
  • your workload is prompt-heavy — input tokens cost $2.00/1M against $10.00/1M.

GPT-6 Astra vs o3: specs, pricing and context

Specification comparison of GPT-6 Astra and o3
FieldGPT-6 AstraOpenAIo3OpenAI
ModelCap Index position#1#46
Index score93.761.0
EvidenceMeasuredMeasured
Input price / 1M tokens$10.00$2.00
Output price / 1M tokens$50.00$8.00
Context window1M tokens200K tokens
Max output tokens128K100K
API providers listed21
Weight accessAPI onlyAPI only
Input modalitiesFile, Image, TextImage, Text, File
First listed4 September 202616 April 2025
PublisherOpenAIOpenAI

Evidence: 4 public benchmark observations across 4 boards · 3 public benchmark observations across 3 boards. Prices are the lowest listed API offer per million tokens observed on the OpenRouter catalogue.

Benchmark scores: GPT-6 Astra vs o3

Public benchmark boards where GPT-6 Astra or o3 has a published result
BoardGPT-6 Astrao3Leads
Arena codingArena (LMArena)—14601454–1466Only one result
LMArena AgentLMArena12.5%10.4%–14.7%Max—Only one result
ARC-AGI-2ARC Prize Foundation95.0%Max6.5%HighGPT-6 Astra
ARC-AGI-3ARC Prize Foundation62.7%Max—Only one result
SWE-benchSWE-bench (Princeton / SWE-agent team)—58.4%Only one result
BFCL V4UC Berkeley (Gorilla)—63.1PromptOnly one result
AA Intelligence IndexArtificial Analysis52.8intelligence-index:v4.3:max—Only one result
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=true—Only one result
AA τ²-Bench TelecomArtificial Analysis—80.7%tau2:telecom:dual-control:pass-at-1:3-repeats:source-model="o3":reasoning=trueOnly one result
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=true20.1%hle:may-2025:text-only-2158:no-tools:pass-at-1:source-model="o3":reasoning=trueGPT-6 Astra
Terminal-Bench 4.0Terminal-Bench (Laude Institute)58.2%55.4%–61.0%Codex · Max—Only one result

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 o3: common questions

Is GPT-6 Astra better than o3?

GPT-6 Astra ranks higher on the ModelCap Index as of 9 September 2026: #1 against #46. 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 do not overlap, but the aggregate Index does not predict performance on every task; compare the relevant benchmark configurations before choosing.

Is GPT-6 Astra cheaper than o3?

o3 is cheaper on output tokens: $8.00/1M against $50.00/1M. Input tokens are $10.00/1M for GPT-6 Astra and $2.00/1M for o3. 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 $8.00 for o3. o3 costs 82.2% 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 o3?

GPT-6 Astra has the larger context window: 1M tokens against 200K.

Which is better for coding, GPT-6 Astra or o3?

The two models do not share a coding benchmark board on ModelCap yet, so no head-to-head coding score is published; the ModelCap Index position is the closest overall signal.

Are GPT-6 Astra and o3 open-weight models?

GPT-6 Astra: API only. o3: 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 o3?

ModelCap currently lists 2 API providers for GPT-6 Astra and 1 for o3, 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 o3 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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