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
$1.00
Output $/MTok
$30.00
$6.00
Cache discount
90% off
90% off
Context
128K
1,000K
Quality
Task confidence comparison
Confidence score from zero to one hundred by task type, where higher is better.
Code Generation
91
vs
70
Code Review
90
vs
68
Summarization
89
vs
84
Q&A
90
vs
85
Extraction
87
vs
89
Reasoning
95
vs
63
Classification
85
vs
91
Creative Writing
91
vs
58
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 reasoning (confidence 95 vs 63)
- -You need strong code generation (confidence 91 vs 70)
- -You need strong creative writing (confidence 91 vs 58)
- -You need strong code review (confidence 90 vs 68)
Choose GPT 5.6 Luna when...
- -You need strong classification (confidence 91 vs 85)
- -You need strong extraction (confidence 89 vs 87)
- -Cost matters: 80% cheaper on input tokens
- -You need a larger context window (1,000K vs 128K)
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
$0.25Cheaper
1M tokens
$12.50
$2.50Cheaper
10M tokens
$125.00
$25.00Cheaper
FAQ
When should I use GPT 5.5 instead of GPT 5.6 Luna?
GPT 5.5 outperforms GPT 5.6 Luna for Reasoning, Code Generation, Code Review. 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 $1.00/MTok vs $5.00/MTok for GPT 5.5, saving 80% on input.
What are the context window sizes for GPT 5.5 and GPT 5.6 Luna?
GPT 5.5 has a 128K token context window. GPT 5.6 Luna has a 1,000K token context window.
Track your real costs
Comparisons show estimated costs at list price. The dashboard reveals your real spend and savings.