GPT-5.6 Luna vs Mistral Large 3
OpenAI against Mistral AI, costed on the same three workloads. GPT-5.6 Luna is cheaper on all three workloads.
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Monthly bill, side by side
| Workload | GPT-5.6 Luna | Mistral Large 3 | Difference |
|---|---|---|---|
| Support chatbot 2,500 six-turn conversations a day |
$887 | $1,609 | $722 (1.8×) |
| Document summarizer 1,000 single-shot summaries a day |
$102 | $219 | $117 (2.1×) |
| Coding agent 200 twelve-turn sessions a day |
$598 | $1,224 | $626 (2×) |
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 Luna | Mistral Large 3 | |
|---|---|---|
| Input, per 1M tokens | $0.2 | $0.5 |
| Output, per 1M tokens | $1.2 | $1.5 |
| Cached input | $0.02 | $0.05 |
| Context window | 922K | 262K |
| Maximum output | 128K | 262K |
| Reasoning model | yes | no |
| Vision | yes | yes |
Beyond the price
- GPT-5.6 Luna reads up to 922K tokens of context in one request; Mistral Large 3 stops at 262K.
- Mistral Large 3 can write up to 262K tokens in one response, against 128K for GPT-5.6 Luna.
- Only GPT-5.6 Luna is a reasoning model, so its output bill also pays for the thinking it does before it answers.
- Only GPT-5.6 Luna offers a batch discount — 50% off both rates for work that can wait.
Run this comparison on your own numbers
Full detail: GPT-5.6 Luna pricing · Mistral Large 3 pricing
More comparisons
Other head-to-heads that include GPT-5.6 Luna or Mistral Large 3.
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- Mistral Large 3 vs Nova 2 Lite
- Mistral Large 3 vs Claude Haiku 4.5
- Mistral Large 3 vs Qwen3 Next 80B
Common questions
Which is cheaper, GPT-5.6 Luna or Mistral Large 3?
GPT-5.6 Luna is cheaper on all three workloads.
How much would GPT-5.6 Luna and Mistral Large 3 cost each month?
On PromptSpend's standard workloads, per month: support chatbot: GPT-5.6 Luna $887, Mistral Large 3 $1,609 (GPT-5.6 Luna is cheaper by $722); document summarizer: GPT-5.6 Luna $102, Mistral Large 3 $219 (GPT-5.6 Luna is cheaper by $117); coding agent: GPT-5.6 Luna $598, Mistral Large 3 $1,224 (GPT-5.6 Luna is cheaper by $626). No prompt caching and no batch discount is assumed.
How do GPT-5.6 Luna and Mistral Large 3 differ apart from price?
GPT-5.6 Luna reads up to 922K tokens of context in one request; Mistral Large 3 stops at 262K. Mistral Large 3 can write up to 262K tokens in one response, against 128K for GPT-5.6 Luna. Only GPT-5.6 Luna is a reasoning model, so its output bill also pays for the thinking it does before it answers. Only GPT-5.6 Luna offers a batch discount — 50% off both rates for work that can wait.