OpenAI: GPT-5.5 Pro vs xAI: Grok 4.20
Side-by-side comparison — pricing, context window, capabilities, and live leaderboard data.
Key differences
- xAI: Grok 4.20 is 96% cheaper per 1K input tokens than OpenAI: GPT-5.5 Pro ($0.0013 vs $0.0300).
- OpenAI: GPT-5.5 Pro is built by OpenAI; xAI: Grok 4.20 is built by xAI.
Specifications
| OpenAI: GPT-5.5 Pro | xAI: Grok 4.20 | |
|---|---|---|
| Provider | OpenAI | xAI |
| Context window | 1050K | 2000K |
| Max output tokens | 8192 | 8192 |
| Input price / 1K tokens | $0.0300 | $0.0013 |
| Output price / 1K tokens | $0.1800 | $0.0025 |
| Vision support | Yes | Yes |
| Function calling | No | No |
| License | Proprietary | Proprietary |
About OpenAI: GPT-5.5 Pro
US·ClosedGPT-5.5 Pro is OpenAI’s high-capability model optimized for deep reasoning and accuracy on complex, high-stakes workloads. It features a 1M+ token context window (922K input, 128K output) with support for...
View OpenAI: GPT-5.5 Pro reliability and benchmark history →About xAI: Grok 4.20
US·ClosedGrok 4.20 is a reasoning model from xAI with industry-leading speed and agentic tool calling capabilities. It combines the lowest hallucination rate on the market with strict prompt adherance, delivering...
View xAI: Grok 4.20 reliability and benchmark history →Try them yourself
Run the same prompt against OpenAI: GPT-5.5 Pro and xAI: Grok 4.20 side-by-side on PromptPit.
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