tokevenGPTvsGPT
GPT 5.5 vs GPT 5.6 Luna
Side-by-side comparison of pricing, task quality, and projected cost at higher scale.
Pricing
Side-by-side pricing
GPT 5.5
FlagshipGPT 5.6 Luna
Fast / BudgetInput $/MTok
$5.00
$0.20
Output $/MTok
$30.00
$1.20
Cache discount
90% off
90% off
Context
1.1M
922K
Quality
Task confidence comparison
Confidence score from zero to one hundred by task type, where higher is better.
Code Generation
65
vs
62
Code Review
90
vs
68
Summarization
70
vs
57
Q&A
90
vs
85
Extraction
78
vs
74
Reasoning
90
vs
86
Classification
85
vs
91
Creative Writing
73
vs
69
GPT 5.5
GPT 5.6 Luna
Guidance
When to use GPT 5.5 vs GPT 5.6 Luna
Choose GPT 5.5 when...
- -You need strong code review (confidence 90 vs 68)
- -You need strong q&a (confidence 90 vs 85)
- -You need strong reasoning (confidence 90 vs 86)
- -You need strong extraction (confidence 78 vs 74)
- -You need a larger context window (1.1M vs 922K)
Choose GPT 5.6 Luna when...
- -You need strong classification (confidence 91 vs 85)
- -Cost matters: 96% cheaper on input tokens
At scale
Cost at scale
Estimated cost assuming a seventy percent input and thirty percent output token split.
GPT 5.5
GPT 5.6 Luna
100K tokens
$1.25
$0.05Cheaper
1M tokens
$20.50
$0.82Cheaper
10M tokens
$205.00
$8.20Cheaper
FAQ
When should I use GPT 5.5 instead of GPT 5.6 Luna?
GPT 5.5 outperforms GPT 5.6 Luna for Code Generation, Code Review, Summarization. It costs $5.00/$30.00 per million tokens (input/output).
Is GPT 5.6 Luna cheaper than GPT 5.5?
Yes. GPT 5.6 Luna input costs $0.20/MTok vs $5.00/MTok for GPT 5.5, saving 96% on input.
What are the context window sizes for GPT 5.5 and GPT 5.6 Luna?
GPT 5.5 has a 1.1M token context window. GPT 5.6 Luna has a 922K token context window.
Go deeper on either model
Per-call cost calculators, provider lineups, and price history for both models on this page.
Other comparisons
How GPT 5.5 and GPT 5.6 Luna stack up against the rest of the field.
Track your real costs
Comparisons show estimated costs at list price. The dashboard reveals your real spend and savings.