Cheaper overall
gpt-5.6-luna
94% lower blended rate
Higher benchmark scores
gpt-5.6-sol
leads on 10 of 11 figures
Cheaper cached input
gpt-5.6-luna
$0.02 vs $0.40, 95% less
Where each one wins
gpt-5.6-luna
- Cheaper input tokens $0.20 vs $4.00, 95% less
- Cheaper output tokens $1.20 vs $20.00, 94% less
- Cheaper cached input $0.02 vs $0.40, 95% less
- Cheaper on all four workloads
- Higher answer reliability (Omniscience Non-Hallucination) 25 vs 10.6
gpt-5.6-sol
- Higher overall intelligence (Intelligence Index) 47 vs 37.3
- Higher coding ability (Coding Index) 78.3 vs 71.4
- Higher multi-step tool use (Agentic Index) 50.2 vs 42.1
- Ahead on 7 more benchmark figures
What four workloads cost
One run, and the same run a thousand times.
gpt-5.6-luna is cheaper on all four workloads, by much the same margin each time — about 18.7 times, from $0.0008 against $0.0140 on a chat turn to $0.1654 against $3.29 on a long document.
| Workload | gpt-5.6-luna | gpt-5.6-sol | ×1,000 | Difference |
|---|---|---|---|---|
| Chat turn 1,000 in / 500 out | $0.0008 | $0.0140 | $0.8000 / $14.00 | gpt-5.6-luna is 94% cheaper |
| RAG answer 10,000 in / 800 out | $0.0030 | $0.0560 | $2.96 / $56.00 | gpt-5.6-luna is 95% cheaper |
| Agent loop 32,000 in / 700 out × 20 calls | $0.0368 | $0.6800 | $36.80 / $680.00 | gpt-5.6-luna is 95% cheaper |
| Long document 400,000 in / 3,000 out | $0.1654 | $3.29 | $165.40 / $3,290.00 | gpt-5.6-luna is 95% cheaper |
Price per 1M tokens
Above 272,000 input tokens the rates change, and the new rate applies to the whole request, not just the tokens past that point: gpt-5.6-luna's input goes from $0.2000 to $0.4000, and gpt-5.6-sol's input goes from $4.00 to $8.00. It does not change which of the two is cheaper.
| Context band | Price | gpt-5.6-luna | gpt-5.6-sol | Difference |
|---|---|---|---|---|
| Prompts up to 272,000 tokens | Input | $0.20 | $4.00 | gpt-5.6-luna is 95% cheaper |
| Prompts up to 272,000 tokens | Cached input | $0.02 | $0.40 | gpt-5.6-luna is 95% cheaper |
| Prompts up to 272,000 tokens | Output | $1.20 | $20.00 | gpt-5.6-luna is 94% cheaper |
| Prompts over 272,000 tokens | Input | $0.40 | $8.00 | gpt-5.6-luna is 95% cheaper |
| Prompts over 272,000 tokens | Cached input | $0.04 | $0.80 | gpt-5.6-luna is 95% cheaper |
| Prompts over 272,000 tokens | Output | $1.80 | $30.00 | gpt-5.6-luna is 94% cheaper |
Blended: gpt-5.6-luna $0.45, gpt-5.6-sol $8.00 per 1M — one rate at 3:1 input to output, for comparing two models at a glance.
Both priced by OpenAI. Standard tier, pay-as-you-go.
Other pricing tiers
Both models offer Batch, Flex and Priority, worth up to 50% off their standard rates, and the cheaper model is the same one on every tier — so the tier you buy changes the bill rather than the choice.
Every tier either model sells is here, so this is the whole price sheet. A saving is measured against that model's own standard rate — how we read tiers.
| Tier | gpt-5.6-luna | gpt-5.6-sol | Cheaper |
|---|---|---|---|
| Batch | $0.10 in / $0.60 out 50% off Standard | $2.00 in / $10.00 out 50% off Standard | gpt-5.6-luna |
| Flex | $0.10 in / $0.60 out 50% off Standard | $2.00 in / $10.00 out 50% off Standard | gpt-5.6-luna |
| Priority | $0.40 in / $2.40 out | $8.00 in / $40.00 out | gpt-5.6-luna |
Benchmarks
They share 11 figures: gpt-5.6-luna leads on 1, gpt-5.6-sol on 10. The widest gap is 16.7 points, on factual accuracy (Omniscience Accuracy).
Overall intelligence
Intelligence Index — Overall intelligence across reasoning, knowledge & math evals
gpt-5.6-sol ahead by 9.7
Coding ability
Coding Index — Coding ability across software-engineering evals
gpt-5.6-sol ahead by 6.9
Multi-step tool use
Agentic Index — Tool use & multi-step agent task performance
gpt-5.6-sol ahead by 8.1
Graduate-level science
GPQA Diamond — Graduate-level questions in biology, chemistry & physics
gpt-5.6-sol ahead by 3
Expert-exam performance
Humanity's Last Exam — Expert-level questions across many academic domains
gpt-5.6-sol ahead by 10
Long-context reasoning
AA-LCR — Long-context reasoning across large inputs
gpt-5.6-sol ahead by 0.3
Scientific coding
SciCode — Research-level scientific coding tasks
gpt-5.6-sol ahead by 4.2
Physics research reasoning
CritPt — Unpublished physics research reasoning problems
gpt-5.6-sol ahead by 11.7
Real-world task performance
GDPval — Economically valuable, real-world knowledge work
gpt-5.6-sol ahead by 7.2
Factual accuracy
Omniscience Accuracy — Breadth of factual knowledge across domains
gpt-5.6-sol ahead by 16.7
Answer reliability
Omniscience Non-Hallucination — How reliably the model avoids fabricated answers
gpt-5.6-luna ahead by 14.4
Each figure is that model's best published run, with the effort level named beside it — where these scores come from.
Specifications
Both list the same capabilities, so nothing here separates them.
| Specification | gpt-5.6-luna | gpt-5.6-sol |
|---|---|---|
| Context window | 1,050,000 tokens | 1,050,000 tokens |
| Max output | 128,000 tokens | 128,000 tokens |
| Takes in | Text, image, file | Text, image, file |
| Puts out | Text | Text |
| Knowledge cutoff | 16 Feb 2026 | 16 Feb 2026 |
| Released | 9 Jul 2026 | 9 Jul 2026 |
| Status | Active | Active |
| Sold by | OpenAI, Perplexity | OpenAI, Perplexity |
| Tool use | Yes | Yes |
| Structured outputs | Yes | Yes |
| Web search | Not listed | Not listed |
| Prompt caching | Yes | Yes |
| Code execution | Yes | Yes |
| Computer use | Not listed | Not listed |
| Open weights | Not listed | Not listed |
| Reasoning | Yes | Yes |
FAQs
- Is gpt-5.6-luna cheaper than gpt-5.6-sol?
- Yes. A 1,000-token prompt with a 500-token reply costs $0.0008 on gpt-5.6-luna and $0.0140 on gpt-5.6-sol, and the same model is cheaper on every workload on this page.
- How much do gpt-5.6-luna and gpt-5.6-sol cost per 1M tokens?
- gpt-5.6-luna costs $0.20 for input and $1.20 for output. gpt-5.6-sol costs $4.00 and $20.00. Standard pay-as-you-go rates, as of 23 Aug 2026.
- Which is better, gpt-5.6-luna or gpt-5.6-sol?
- On published benchmarks, gpt-5.6-sol. It leads on 10 of the 11 figures both models report, including overall intelligence (Intelligence Index), where it scores 47 against 37.3.
- Is Batch pricing cheaper for gpt-5.6-luna or gpt-5.6-sol?
- Batch input costs $0.10 on gpt-5.6-luna and $2.00 on gpt-5.6-sol, 50% below the standard rate on both.