Standard Compute
Model comparison 2026

GPT-5.6 Luna vs GPT-6 Astra

GPT-5.6 Luna
OpenAI · Budget · Proprietary
$0.50/1M · 1.1M ctx
GPT-6 Astra
OpenAI · Frontier · Proprietary
$22/1M · 1.1M ctx

Community vote

Pick a winner in each dimension. You can change your vote any time.

Output Quality
Correctness and depth of what it produces
Agentic Ability
Tool calls, instruction-following, and multi-step tasks
Speed
Tokens per second and time-to-first-token
Value for money
How much capability you get per dollar
Reliability
Consistent results: fewer refusals, loops and format breaks

Specs and pricing side by side

Spec
GPT-5.6 Luna
GPT-6 Astra
Maker
OpenAI
OpenAI
Blended price / 1M
$0.50
$22
Input / output
$0.20 in · $1.20 out / 1M tokens
$10 in · $50 out / 1M tokens
Context window
1.1M
1.1M
Open weights
No
No
Tool use
Yes
Yes
Reasoning
Yes
Yes
Output Quality
8.4
9.7
Agentic Ability
8.3
9.7
Speed
9.3
6.8
Value for money
9.0
6.9
Reliability
9.1
9.3

Pricing and capabilities synced from the OpenRouter catalogue. Scores are editorial (0–10).

Verdict: GPT-5.6 Luna or GPT-6 Astra?

Updated 2026-10-13

Choose GPT-5.6 Luna if you want cheap, fast subtasks, routing, and subagents in OpenAI-based stacks. Choose GPT-6 Astra if you want the hardest coding and research tasks in OpenAI-based stacks, where cost is secondary.

In our editorial scoring, GPT-6 Astra leads in 3 of five dimensions (output quality, agentic ability and reliability), while GPT-5.6 Luna leads in 2. On price, GPT-5.6 Luna runs about $0.50 per 1M tokens (blended) and is proprietary; GPT-6 Astra is about $22 and proprietary.

Where GPT-5.6 Luna falls short
  • Clear quality step below Terra and Sol
  • Superseded by GPT-6 Luna, which is cheaper ($0.10/$0.50) and stronger
Full GPT-5.6 Luna breakdown →
Where GPT-6 Astra falls short
  • Five times GPT-6.1 Sol's price for a small measured gain
  • Slow: about 66 output tokens/s at max effort
Full GPT-6 Astra breakdown →

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