Comparison
Grok vs GPT-5: xAI's flagship against OpenAI's
Grok's aggressive pricing and reasoning focus against the GPT-5 line.
Editorial updated 21 Sept 2026
Source: OpenRouter (live)
xAI's Grok has moved from novelty to a genuine contender, particularly on reasoning-heavy tasks and on price at the top tier. GPT-5 remains the safer default for most teams because of ecosystem depth, but the gap has narrowed enough that the comparison is worth running.
Look at the reasoning and context rows. Grok's listing has tended to emphasise long context and reasoning mode; GPT-5's strengths are breadth, tooling and structured output. Pricing between the two has swapped places more than once, so trust the live figures rather than memory.
Live figures
The numbers
Best value in each row is highlighted. “Not declared” means the provider does not advertise the feature on its listing.
| Attribute | ||
|---|---|---|
| Input priceUSD per 1M tokens | $2.00 | $0.20 (best) |
| Output priceUSD per 1M tokens | $6.00 | $1.20 (best) |
| Blended price75% in / 25% out | $3.00 | $0.45 (best) |
| Vs. market median | 3.8× dearer | 44% cheaper |
| Value rankcheapest = 1 | #318 | #143 (best) |
| Context windowtokens | 500K | 1.1M (best) |
| Max outputtokens | 450K (best) | 128K |
| Input modalities | text, image, file | file, image, text |
| Output modalities | text | text |
| Tool calling | Declared | Declared |
| Reasoning | Declared | Declared |
| Structured output | Declared | Declared |
| Listed on OpenRouter | 2026-08-12 (best) | 2026-07-09 |
Blended price assumes a 3:1 input-to-output token mix. Median is across all 417 priced models.
Add or swap modelsRead-out
What the numbers say
- OpenAI: GPT-5.6 Luna Pro is the cheapest here at $0.45/M blended — 6.7× less than SpaceXAI: Grok 4.6.
- OpenAI: GPT-5.6 Luna Pro offers the largest context window (1.1M tokens) versus 500K for SpaceXAI: Grok 4.6.
Our view
Which should you choose?
- Grok 4.6
- Choose Grok for reasoning-heavy workloads where its current price undercuts GPT-5.
- GPT-5.6 Luna Pro
- Choose GPT-5 for ecosystem breadth, tool support and predictable structured output.
Models
Model pages
Full pricing history, capabilities and alternatives for each model in this comparison.
$3.00
/M blended
OpenAI
$0.450
/M blended
More comparisons
Other head-to-heads
- Claude vs GPT-5: which frontier model should you pay for?
Anthropic's flagship Claude against OpenAI's GPT-5 line on price, context and declared capabilities, with live figures.
- Claude Sonnet vs GPT-5 Mini: the mid-tier workhorses
The two models most production apps actually run. How the price gap compares to the capability gap.
- Gemini vs GPT-5: Google's flagship against OpenAI's
Gemini's very long context and multimodal input against GPT-5's ecosystem and pricing.
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