GPT-5.6 Terra vs Grok 4.5
OpenAI against xAI, costed on the same three workloads. Grok 4.5 is cheaper on all three workloads.
Monthly bill, side by side
| Workload | GPT-5.6 Terra | Grok 4.5 | Difference |
|---|---|---|---|
| Support chatbot 2,500 six-turn conversations a day |
$8,865 | $6,435 | $2,430 (+38%) |
| Document summariser 1,000 single-shot summaries a day |
$1,020 | $876 | $144 (+16%) |
| Coding agent 200 twelve-turn sessions a day |
$5,976 | $4,896 | $1,080 (+22%) |
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-5.6 Terra | Grok 4.5 | |
|---|---|---|
| Input, per 1M tokens | $2 | $2 |
| Output, per 1M tokens | $12 | $6 |
| Cached input | $0.2 | $0.5 |
| Context window | 1.05M | 500K |
| Maximum output | 128K | 500K |
| Reasoning model | yes | yes |
| Vision | yes | yes |
Run this comparison on your own numbers
Full detail: GPT-5.6 Terra pricing · Grok 4.5 pricing