GPT-6 Astra (OpenAI) and o4 Mini (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 #87); o4 Mini is 11.4× cheaper per output token ($4.40/1M vs $50.00/1M); and GPT-6 Astra offers the longer context window (1M vs 200K tokens).
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 o4 Mini
Public benchmark boards where GPT-6 Astra or o4 Mini has a published result
GPT-6 Astra ranks higher on the ModelCap Index as of 9 September 2026: #1 against #87. 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 o4 Mini?
o4 Mini is cheaper on output tokens: $4.40/1M against $50.00/1M. Input tokens are $10.00/1M for GPT-6 Astra and $1.10/1M for o4 Mini. 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 $4.40 for o4 Mini. o4 Mini costs 90.2% 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 o4 Mini?
GPT-6 Astra has the larger context window: 1M tokens against 200K.
Which is better for coding, GPT-6 Astra or o4 Mini?
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 o4 Mini open-weight models?
GPT-6 Astra: API only. o4 Mini: 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 o4 Mini?
ModelCap currently lists 2 API providers for GPT-6 Astra and 1 for o4 Mini, 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 o4 Mini 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.