Standard Compute
Model comparison 2026

GPT-5.6 Sol vs GPT-6 Luna

GPT-5.6 Sol
OpenAI · Frontier · Proprietary
$4.40/1M · 1.1M ctx
GPT-6 Luna
OpenAI · Budget · Proprietary
$0.22/1M · 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 Sol
GPT-6 Luna
Maker
OpenAI
OpenAI
Blended price / 1M
$4.40
$0.22
Input / output
$2.00 in · $10 out / 1M tokens
$0.10 in · $0.50 out / 1M tokens
Context window
1.1M
1.1M
Open weights
No
No
Tool use
Yes
Yes
Reasoning
Yes
Yes
Output Quality
9.5
8.7
Agentic Ability
9.4
8.5
Speed
7.4
9.3
Value for money
7.8
9.4
Reliability
9.3
9.1

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

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

Updated 2026-10-13

Choose GPT-5.6 Sol if you want hard coding and research tasks for teams in the OpenAI ecosystem. Choose GPT-6 Luna if you want cheap, fast subtasks, routing and subagents in OpenAI-based stacks.

In our editorial scoring, GPT-5.6 Sol leads in 3 of five dimensions (output quality, agentic ability and reliability), while GPT-6 Luna leads in 2. On price, GPT-5.6 Sol runs about $4.40 per 1M tokens (blended) and is proprietary; GPT-6 Luna is about $0.22 and proprietary.

Where GPT-5.6 Sol falls short
  • Superseded by GPT-6.1 Sol, which scores well above it on agent benchmarks
  • Slower and pricier than Terra for routine work
Full GPT-5.6 Sol breakdown →
Where GPT-6 Luna falls short
  • Weak on long agentic runs (16.4% on Terminal-Bench 4.0)
  • Clear quality step below GPT-6.1 Sol
Full GPT-6 Luna breakdown →

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