GPT 5.5
OpenAI · text, image, pdf → text
Input$2 /M
Output$0 /M
← ModelsGPT 5.5GPT 5.6 Luna
GPT 5.5 vs GPT 5.6 Luna
Compare GPT 5.5 from OpenAI and GPT 5.6 Luna from OpenAI on key metrics including benchmarks, price, context length, and other model features. Access both models and hundreds of others through the AIHubMix API.
GPT 5.5GPT 5.6 Luna+ Add model · 2/4
GPT 5.6 Luna
OpenAI · text, image → text
GPT-5.6 Luna is designed for cost-sensitive, high-volume workloads. It roughly corresponds to the nano model tier used in earlier GPT-5 families.
Input$1 /M
Output$6 /M
Cache read$0.1 /M
Pricing & Specifications
Prices are per million tokens. Time to First Token and throughput are rolling averages measured on AIHubMix.
GPT 5.5
GPT 5.6 Luna
Input /M
$2
$1
Output /M
$0
$6
Cache read /M
-
$0.1
Context length
1,050,000
1,050,000
Max output
128,000
128,000
Time to First Token
6.4 s
2.2 s
Throughput
45.6 tok/s
88.4 tok/s
Modalities
textimagepdf
textimage
Supported Parameters
toolsthinkingstructured outputs
API Formats
chat_completions · responses
Released
-
-
Promotional prices show the discounted rate; see each model page for promotion windows.
Activity Past 30 Days
Daily traffic served through AIHubMix — how demand for each model is trending.
gpt-5.5gpt-5.6-luna
Tokens / day
-
Requests / day
-
Performance Past 3 Days
Measured on real AIHubMix traffic, hourly buckets. Gaps mean no traffic in that hour.
gpt-5.5gpt-5.6-luna
Throughput (tok/s)
-
TTFT (s)
-
Uptime (%)
-
Cost calculator
Estimate your monthly bill for the same workload on each model.
GPT 5.5
$120 /mo
GPT 5.6 Luna
$150 /mo
Monthly = daily × 30. Discounted rates applied where a promotion is active.
FAQ
Which responds faster?
GPT 5.6 Luna: 2.2s time to first token measured on AIHubMix; see the live performance charts above for how each model behaves across the day.
How large is each context window?
GPT 5.5 accepts 1,050,000 and GPT 5.6 Luna accepts 1,050,000 input tokens. Maximum output per request is 128,000 tokens on GPT 5.5 and 128,000 tokens on GPT 5.6 Luna.
Which one generates tokens faster?
GPT 5.6 Luna at 88.4 tok/s and GPT 5.5 at 45.6 tok/s, measured as output throughput on AIHubMix — a separate metric from time to first token.
What inputs and capabilities does each model support?
GPT 5.5 accepts text, image and PDF input; GPT 5.6 Luna accepts text and image input and supports tool calling, thinking and structured outputs.
Can I call GPT 5.5 and GPT 5.6 Luna with the same API key?
Yes. AIHubMix serves every model on this page behind one OpenAI-compatible endpoint, so switching between them is a one-line change to the model field — no second account, key or SDK.
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