GPT-5.5 Pro vs Grok 4.3
Benchmarks, API pricing and specs, head to head. Data updated 2026-06-10.
GPT-5.5 Pro
OpenAI · Apr 2026
The maximum-compute tier of GPT-5.5 for the hardest research, math and engineering problems, at a steep per-token premium.
Grok 4.3
xAI · Apr 2026
xAI's frontier model: 1M context at $1.25/$2.50, ~168 tokens/sec, and a record low hallucination rate on independent testing.
The verdict
These two models don't yet share verified results on the benchmarks we track, so judge them on specs, pricing and intended use. On price the gap is dramatic: Grok 4.3 works out roughly 43x cheaper per blended million tokens.
Specs & pricing
| GPT-5.5 Pro | Grok 4.3 | |
|---|---|---|
| modhub Index | — | — |
| Input price / 1M | $30 | $1.25 |
| Output price / 1M | $180 | $2.5 |
| Context window | 1M | 1M |
| Max output | 128K | — |
| Open weights | no | no |
| Reasoning model | yes | yes |
| Multimodal input | text, image | text, image |
| Knowledge cutoff | Jan 2026 | Mar 2026 |
| Released | Apr 2026 | Apr 2026 |
| Example monthly cost* | $570.00 | $16.25 |
* 10M input + 1.5M output tokens per month at list prices, no caching. Green = better value on that row.
Frequently asked questions
- Which is better, GPT-5.5 Pro or Grok 4.3?
- These two models don't yet share verified results on the benchmarks we track, so judge them on specs, pricing and intended use. On price the gap is dramatic: Grok 4.3 works out roughly 43x cheaper per blended million tokens.
- Which is cheaper, GPT-5.5 Pro or Grok 4.3?
- GPT-5.5 Pro costs $30/$180 per million input/output tokens, while Grok 4.3 costs $1.25/$2.5. For a typical workload of 10M input and 1.5M output tokens per month, that's $570.00 versus $16.25.
- Which model is better for coding, GPT-5.5 Pro or Grok 4.3?
- We don't yet track SWE-bench Verified results for both models; check their individual pages for coding-related scores.