GPT-5.1 vs Grok 4.3
OpenAI against xAI, costed on the same three workloads. Grok 4.3 is cheaper on all three workloads.
Monthly bill, side by side
| Workload | GPT-5.1 | Grok 4.3 | Difference |
|---|---|---|---|
| Support chatbot 2,500 six-turn conversations a day |
$6,553 | $3,516 | $3,038 (1.9×) |
| Document summariser 1,000 single-shot summaries a day |
$698 | $518 | $180 (+35%) |
| Coding agent 200 twelve-turn sessions a day |
$4,185 | $2,835 | $1,350 (+48%) |
No prompt caching and no batch discount on either side, so the comparison is like for like. Both figures assume 30 days a month.
The rate cards
| GPT-5.1 | Grok 4.3 | |
|---|---|---|
| Input, per 1M tokens | $1.25 | $1.25 |
| Output, per 1M tokens | $10 | $2.5 |
| Cached input | $0.125 | $0.2 |
| Context window | 272K | 1M |
| Maximum output | 128K | 1M |
| Reasoning model | yes | yes |
| Vision | yes | yes |
Run this comparison on your own numbers
Full detail: GPT-5.1 pricing · Grok 4.3 pricing