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GPT 5.5 (free) vs Grok 4.5

Compare GPT 5.5 (free) from OpenAI and Grok 4.5 from Grok on key metrics including benchmarks, price, context length, and other model features. Access both models and hundreds of others through the AIHubMix API.

OpenAIGPT 5.5 (free)GrokGrok 4.5
+ Add model · 2/4
OpenAI logo
GPT 5.5 (free)
OpenAI · text, image → text

This free model API comes from the OpenAI model deployed on Azure. To prevent abuse, the external content filter provided by Azure has been enforced, which will result in additional delays. If you want to experience the full version of the model API without filters, please use the paid version and request the model name ID without "-free". To maintain reliable service, each account is limited to 5 requests per minute, 500 requests per day, and 1 million tokens per day.

Input$0.00 /M
Output$0.00 /M
Details
Grok logo
Grok 4.5
Grok · text, image → text

Grok 4.5 was trained on datasets spanning knowledge in coding, science, engineering, and math. With both intelligent and efficient reasoning, Grok 4.5 excels at real engineering tasks and exceeds comparable leading models at these tasks.

Input$2.00 /M
Output$6.00 /M
Details

Pricing & Specifications

Prices are per million tokens. Time to First Token and throughput are rolling averages measured on AIHubMix.

GPT 5.5 (free)
Grok 4.5
Input /M
$0.00
$2.00
Output /M
$0.00
$6.00
Cache read /M
$0.00
$0.50
Context length
1,050,000
500,000
Max output
128,000
500,000
Time to First Token
3.6 s
1.5 s
Throughput
42.0 tok/s
27.6 tok/s
Modalities
textimage
textimage
Supported Parameters
thinkingfunction callingstructured outputswebtools
thinkingtoolsfunction callingstructured outputslong context
API Formats
Released
-
July 2026

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-5.5-freegrok-4.5

Tokens / day

-

Requests / day

-

Performance Past 3 Days

Measured on real AIHubMix traffic, hourly buckets. Gaps mean no traffic in that hour.

gpt-5.5-freegrok-4.5

Throughput (tok/s)

-

TTFT (s)

-

Uptime (%)

-

Cost calculator

Estimate your monthly bill for the same workload on each model.

GPT 5.5 (free)
$0.00 /mo
Grok 4.5
$210 /mo

Monthly = daily × 30. Discounted rates applied where a promotion is active.

FAQ

Which responds faster?

Grok 4.5: 1.5s 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 (free) accepts 1,050,000 and Grok 4.5 accepts 500,000 input tokens. Maximum output per request is 128,000 tokens on GPT 5.5 (free) and 500,000 tokens on Grok 4.5.

Which one generates tokens faster?

GPT 5.5 (free) at 42.0 tok/s and Grok 4.5 at 27.6 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 (free) accepts text and image input and supports thinking, function calling, structured outputs, web search and tool calling; Grok 4.5 accepts text and image input and supports thinking, tool calling, function calling, structured outputs and long context.

Can I call GPT 5.5 (free) and Grok 4.5 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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