GPT-5 mini vs Grok 3 mini
Grok 3 mini is cheaper for every workload modelled here.
List prices checked
Specifications and rates
| Property | GPT-5 mini | Grok 3 mini |
|---|---|---|
| Input per 1M | $0.250 | $0.300 |
| Output per 1M | $2.00 | $0.500 |
| Cached input per 1M | $0.025 | — |
| Blended (3:1) | $0.688 | $0.350 |
| Context window | 400K | 131K |
| Max output | 128K | — |
| Inputs accepted | text, image | text |
Source: OpenAI pricing (May 2026) · xAI pricing (May 2026). Published list prices only — committed-use discounts, regional variation, and per-request charges are not included. Not yet independently re-checked against the vendor’s page.
Monthly cost by workload
Identical token volumes through both rate cards. Output-heavy profiles are where the ranking flips.
| Workload | GPT-5 mini | Grok 3 mini | Cheaper |
|---|---|---|---|
| In-app chat assistantA support or help assistant handling a few thousand conversations a month, with short prompts and short answers. | $15 | $8.50 | Grok 3 minisaves $6.50/mo (43%) |
| RAG over documentsRetrieval-augmented answering where each request stuffs several retrieved passages into the prompt, so input dominates. | $105 | $98 | Grok 3 minisaves $7.50/mo (7%) |
| Coding agentAn agentic loop that reads files and writes patches, generating heavy output and re-sending large context on every turn. | $300 | $170 | Grok 3 minisaves $130/mo (43%) |
What each one is for
GPT-5 mini
by OpenAI
A fifth of GPT-5's price with the same 400k context window, which makes it the cheapest way to process very long documents without dropping to a small model.
Grok 3 mini
by xAI
An unusually cheap reasoning model, with output priced below most competitors' input rates — which matters because reasoning models are output-heavy by nature.
Common questions
- Is GPT-5 mini or Grok 3 mini cheaper in 2026?
- Grok 3 mini, for every workload modelled here. On a blended 3:1 basis it costs $0.350 per million tokens against GPT-5 mini's $0.688.
- Which has the larger context window?
- GPT-5 mini, at 400K tokens against 131K. A larger window only helps if you can afford to fill it — the cost of one full-context request is in the table above.
- Which is cheaper for output-heavy work like agents?
- Grok 3 mini, at $0.500 per million output tokens against $2.00. Reasoning tokens bill as output, so for agentic loops this axis usually decides the invoice regardless of what the input rates look like.
- What is not included in these figures?
- Batch-processing discounts, fine-tuning, long-context surcharges above a provider's standard tier, and any enterprise agreement. These are published pay-as-you-go list prices, checked against each provider's own pricing page on the date shown.
- Is switching from GPT-5 mini to Grok 3 mini worth it?
- On price alone it is about 49% cheaper on a blended basis. Whether that survives contact with your workload depends on output quality and on retry rate — a cheaper model that needs two attempts is not cheaper. Model the specific volumes in the calculator before you migrate.