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Head-to-head comparison

GPT-5.4 Nano vs GPT-6 Astra

GPT-5.4 Nano (OpenAI) and GPT-6 Astra (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 #72); GPT-5.4 Nano is 40× cheaper per output token ($1.25/1M vs $50.00/1M); and GPT-6 Astra offers the longer context window (1M vs 400K tokens).

Which should you choose?

Choose GPT-5.4 Nano if…

  • API cost matters — $1.25/1M output tokens against $50.00/1M, about 40× cheaper.
  • your workload is prompt-heavy — input tokens cost $0.20/1M against $10.00/1M.

Choose GPT-6 Astra if…

  • you want the stronger overall ModelCap Index position — #1 against #72 (93.7 vs 50.5 points).
  • you need the longer context window — 1M tokens against 400K.
  • ARC-AGI-2 is your yardstick — 95.0% against 5.7%.
  • AA Intelligence Index is your yardstick — 52.8 against 21.2.
  • AA Terminal-Bench 2.1 is your yardstick — 88.4% against 60.7%.
  • AA Humanity's Last Exam is your yardstick — 54.7% against 28.3%.
  • you want the more recently listed model — GPT-6 Astra was listed 4 September 2026, GPT-5.4 Nano 17 March 2026.

GPT-5.4 Nano vs GPT-6 Astra: specs, pricing and context

Specification comparison of GPT-5.4 Nano and GPT-6 Astra
FieldGPT-5.4 NanoOpenAIGPT-6 AstraOpenAI
ModelCap Index position#72#1
Index score50.593.7
EvidenceMeasuredMeasured
Input price / 1M tokens$0.20$10.00
Output price / 1M tokens$1.25$50.00
Context window400K tokens1M tokens
Max output tokens128K128K
API providers listed22
Weight accessAPI onlyAPI only
Input modalitiesFile, Image, TextFile, Image, Text
First listed17 March 20264 September 2026
PublisherOpenAIOpenAI

Evidence: 4 public benchmark observations across 4 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-5.4 Nano vs GPT-6 Astra

Public benchmark boards where GPT-5.4 Nano or GPT-6 Astra has a published result
BoardGPT-5.4 NanoGPT-6 AstraLeads
Arena codingArena (LMArena)14601454–1466High—Only one result
LMArena AgentLMArena—12.5%10.4%–14.7%MaxOnly one result
ARC-AGI-2ARC Prize Foundation5.7%X-High95.0%MaxGPT-6 Astra
ARC-AGI-3ARC Prize Foundation—62.7%MaxOnly one result
AA Intelligence IndexArtificial Analysis21.2intelligence-index:v4.3:xhigh52.8intelligence-index:v4.3:maxGPT-6 Astra
AA Terminal-Bench 2.1Artificial Analysis60.7%terminal-bench:2.1:terminus-2:e2b:pass-at-1:3-repeats:source-model="GPT-5.4 nano (xhigh)":reasoning=true88.4%terminal-bench:2.1:terminus-2:e2b:pass-at-1:3-repeats:source-model="GPT-6 Astra (max)":reasoning=trueGPT-6 Astra
AA τ²-Bench TelecomArtificial Analysis76.0%tau2:telecom:dual-control:pass-at-1:3-repeats:source-model="GPT-5.4 nano (xhigh)":reasoning=true—Only one result
AA Humanity's Last ExamArtificial Analysis28.3%hle:may-2025:text-only-2158:no-tools:pass-at-1:source-model="GPT-5.4 nano (xhigh)":reasoning=true54.7%hle:may-2025:text-only-2158:no-tools:pass-at-1:source-model="GPT-6 Astra (max)":reasoning=trueGPT-6 Astra
Terminal-Bench 4.0Terminal-Bench (Laude Institute)—58.2%55.4%–61.0%Codex · MaxOnly 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-5.4 Nano vs GPT-6 Astra: common questions

Is GPT-5.4 Nano better than GPT-6 Astra?

GPT-6 Astra ranks higher on the ModelCap Index as of 9 September 2026: #1 against #72. 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-5.4 Nano cheaper than GPT-6 Astra?

GPT-5.4 Nano is cheaper on output tokens: $1.25/1M against $50.00/1M. Input tokens are $0.20/1M for GPT-5.4 Nano and $10.00/1M for GPT-6 Astra. 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 $1.02 for GPT-5.4 Nano versus $45.00 for GPT-6 Astra. GPT-5.4 Nano costs 97.7% 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-5.4 Nano or GPT-6 Astra?

GPT-6 Astra has the larger context window: 1M tokens against 400K.

Which is better for coding, GPT-5.4 Nano or GPT-6 Astra?

AA Terminal-Bench 2.1: GPT-5.4 Nano 60.7%, GPT-6 Astra 88.4% — GPT-6 Astra leads.

Are GPT-5.4 Nano and GPT-6 Astra open-weight models?

GPT-5.4 Nano: API only. GPT-6 Astra: 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-5.4 Nano and GPT-6 Astra?

ModelCap currently lists 2 API providers for GPT-5.4 Nano and 2 for GPT-6 Astra, from the OpenRouter catalogue snapshot the site serves; each model page lists the providers and their prices.

How current is this GPT-5.4 Nano vs GPT-6 Astra 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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