Claude Sonnet 5 vs GPT-5.5
Anthropic against OpenAI, costed on the same three workloads. Claude Sonnet 5 is cheaper on all three workloads.
Monthly bill, side by side
| Workload | Claude Sonnet 5 | GPT-5.5 | Difference |
|---|---|---|---|
| Support chatbot 2,500 six-turn conversations a day |
$8,055 | $22,163 | $14,108 (2.8×) |
| Document summariser 1,000 single-shot summaries a day |
$972 | $2,550 | $1,578 (2.6×) |
| Coding agent 200 twelve-turn sessions a day |
$5,616 | $14,940 | $9,324 (2.7×) |
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
| Claude Sonnet 5 | GPT-5.5 | |
|---|---|---|
| Input, per 1M tokens | $3 | $5 |
| Output, per 1M tokens | $15 | $30 |
| Cached input | $0.3 | $0.5 |
| Context window | 1M | 1.05M |
| Maximum output | 128K | 128K |
| Reasoning model | yes | yes |
| Vision | yes | yes |
Run this comparison on your own numbers
Full detail: Claude Sonnet 5 pricing · GPT-5.5 pricing