token.app › Compare › GPT-5.5 vs GPT-5.6 Luna
GPT-5.5 vs GPT-5.6 Luna
GPT-5.5 and GPT-5.6 Luna split the 4 shared benchmarks evenly. GPT-5.6 Luna is 50× cheaper per token on a blended 3:1 basis.
Head to head
Blended price uses a 3:1 input:output mix
| GPT-5.5 | GPT-5.6 Luna | |
|---|---|---|
| Provider | OpenAI | OpenAI |
| Input $/1M | $5.00 | $0.100 |
| Output $/1M | $30.00 | $0.600 |
| Blended $/1M | $11.25 | $0.225 |
| Context window | 1.1M | 1.1M |
| Max output | 128K | 128K |
| Released | Apr 2026 | Jul 2026 |
| Licence | Proprietary | Proprietary |
| GPQA Diamond | 90.7% | 91.6% |
| FrontierMath T1–3 | 85.3% | 82.1% |
| FrontierMath T4 | 72.5% | 61.0% |
| OTIS Mock AIME | 84.4% | 98.3% |
Benchmark scores independently run and published by Epoch AI, 'AI Benchmarking Hub', used under CC BY 4.0. Only benchmarks with a score for BOTH models are compared.
Choose GPT-5.5 if…
- Higher FrontierMath T1–3 (85.3% vs 82.1%)
- Higher FrontierMath T4 (72.5% vs 61.0%)
Choose GPT-5.6 Luna if…
- Costs less per token — $0.225 vs $11.25 blended
- Higher GPQA Diamond (91.6% vs 90.7%)
- Higher OTIS Mock AIME (98.3% vs 84.4%)
- Newer model (released Jul 2026)
FAQ
Which is better, GPT-5.5 or GPT-5.6 Luna?
Across the 4 benchmarks both models have independently-run scores for, GPT-5.5 leads on 2 and GPT-5.6 Luna leads on 2. Benchmarks are one input — price and context window are on this page too.
Is GPT-5.5 cheaper than GPT-5.6 Luna?
GPT-5.6 Luna is cheaper: $0.225 versus $11.25 per million tokens blended at 3:1 input:output. Input alone: $5.00 vs $0.100. Output alone: $30.00 vs $0.600.
What context windows do GPT-5.5 and GPT-5.6 Luna have?
GPT-5.5: 1,050,000 tokens. GPT-5.6 Luna: 1,050,000 tokens.
Who makes GPT-5.5 and GPT-5.6 Luna?
GPT-5.5 is made by OpenAI. GPT-5.6 Luna is made by OpenAI.