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Head-to-head comparison

Gemini 3.5 Flash Lite vs GPT-6 Astra

Gemini 3.5 Flash Lite (Google) 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 #30); and Gemini 3.5 Flash Lite is 20× cheaper per output token ($2.50/1M vs $50.00/1M).

Which should you choose?

Choose Gemini 3.5 Flash Lite if…

  • API cost matters — $2.50/1M output tokens against $50.00/1M, about 20× cheaper.
  • your workload is prompt-heavy — input tokens cost $0.30/1M against $10.00/1M.

Choose GPT-6 Astra if…

  • you want the stronger overall ModelCap Index position — #1 against #30 (93.7 vs 67.1 points).
  • LMArena Agent is your yardstick — 12.5% against -13.4%.
  • ARC-AGI-2 is your yardstick — 95.0% against 10.3%.
  • AA Intelligence Index is your yardstick — 52.8 against 22.7.
  • AA Terminal-Bench 2.1 is your yardstick — 88.4% against 53.6%.
  • AA Humanity's Last Exam is your yardstick — 54.7% against 18.8%.
  • you want the more recently listed model — GPT-6 Astra was listed 4 September 2026, Gemini 3.5 Flash Lite 21 July 2026.

Gemini 3.5 Flash Lite vs GPT-6 Astra: specs, pricing and context

Specification comparison of Gemini 3.5 Flash Lite and GPT-6 Astra
FieldGemini 3.5 Flash LiteGoogleGPT-6 AstraOpenAI
ModelCap Index position#30#1
Index score67.193.7
EvidenceMeasuredMeasured
Input price / 1M tokens$0.30$10.00
Output price / 1M tokens$2.50$50.00
Context window1M tokens1M tokens
Max output tokens66K128K
API providers listed22
Weight accessAPI onlyAPI only
Input modalitiesText, Image, Video, File, AudioFile, Image, Text
First listed21 July 20264 September 2026
PublisherGoogleOpenAI

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: Gemini 3.5 Flash Lite vs GPT-6 Astra

Public benchmark boards where Gemini 3.5 Flash Lite or GPT-6 Astra has a published result
BoardGemini 3.5 Flash LiteGPT-6 AstraLeads
Arena codingArena (LMArena)15021494–1511—Only one result
LMArena AgentLMArena-13.4%-14.9%–-12.0%12.5%10.4%–14.7%MaxGPT-6 Astra
ARC-AGI-2ARC Prize Foundation10.3%High95.0%MaxGPT-6 Astra
ARC-AGI-3ARC Prize Foundation—62.7%MaxOnly one result
AA Intelligence IndexArtificial Analysis22.7intelligence-index:v4.3:reasoning-unspecified52.8intelligence-index:v4.3:maxGPT-6 Astra
AA Terminal-Bench 2.1Artificial Analysis53.6%terminal-bench:2.1:terminus-2:e2b:pass-at-1:3-repeats:source-model="Gemini 3.5 Flash-Lite":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 Humanity's Last ExamArtificial Analysis18.8%hle:may-2025:text-only-2158:no-tools:pass-at-1:source-model="Gemini 3.5 Flash-Lite":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.

Gemini 3.5 Flash Lite vs GPT-6 Astra: common questions

Is Gemini 3.5 Flash Lite better than GPT-6 Astra?

GPT-6 Astra ranks higher on the ModelCap Index as of 9 September 2026: #1 against #30. 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 Gemini 3.5 Flash Lite cheaper than GPT-6 Astra?

Gemini 3.5 Flash Lite is cheaper on output tokens: $2.50/1M against $50.00/1M. Input tokens are $0.30/1M for Gemini 3.5 Flash Lite 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 $1.85 for Gemini 3.5 Flash Lite versus $45.00 for GPT-6 Astra. Gemini 3.5 Flash Lite costs 95.9% 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, Gemini 3.5 Flash Lite or GPT-6 Astra?

Both publish a 1M-token context window.

Which is better for coding, Gemini 3.5 Flash Lite or GPT-6 Astra?

AA Terminal-Bench 2.1: Gemini 3.5 Flash Lite 53.6%, GPT-6 Astra 88.4% — GPT-6 Astra leads.

Are Gemini 3.5 Flash Lite and GPT-6 Astra open-weight models?

Gemini 3.5 Flash Lite: 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 Gemini 3.5 Flash Lite and GPT-6 Astra?

ModelCap currently lists 2 API providers for Gemini 3.5 Flash Lite 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 Gemini 3.5 Flash Lite 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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