Grok 4.5 vs Gemini 3.1 Pro
Side-by-side comparison of API pricing, specs, benchmarks, and capabilities
| Specification |
by xAI
|
by Google
|
|---|---|---|
| Overview | ||
| Status | Current flagship | Current flagship |
| Released | Jul 8, 2026 | Feb 19, 2026 |
| Pricing per million tokens | ||
| Input | $2.00/Mtok | $2.00/Mtok |
| Output | $6.00/Mtok | $12.00/Mtok |
| Blended avg | $3.00/Mtok | $4.50/Mtok |
| Cached input | — | $0.200/Mtok |
| Specifications | ||
| Context window | 500K tokens | 2M tokens |
| Parameters | Proprietary | Proprietary |
| Speed (TPS) | — | — |
| Modalities | ||
| Input |
textimage
|
textimageaudiovideo
|
| Benchmarks sources: Artificial Analysis, LMSYS Chatbot Arena (UC Berkeley), xAI Grok 4.5 launch post / Vellum LLM Leaderboard | ||
| Terminal-Bench 2.1 | 83.3 vendor | 70.3 |
| Avg benchmark score | — | 74.8 |
| Perf / dollar | — | 16.6 |
| GPQA Diamond | — | 94.3 |
| MCP Atlas | — | 69.2 |
| BrowseComp | — | 85.9 |
| OSWorld-Verified | — | 76.2 |
| Humanity's Last Exam | — | 44.4 |
| ARC-AGI 2 | — | 77.1 |
| HumanEval | — | 80.6 |
| Independent composite scores each on its own scale — not part of the average above | ||
| AA Intelligence Index | 55.8 | 47.7 |
| AA Agentic Index | 48.9 | 23 |
| AA-Omniscience Index (−100–100) | 25.3 | 31.9 |
| LMSYS Chatbot Arena | 1469.6 ELO | 1486.7 ELO |
| GDPval-AA v2 | 1526.4 ELO | — |
| Providers | ||
| Available from |
xAI — $2.00/$6.00/Mtok
|
Google — $2.00/$12.00/Mtok
|
Cost at scale
1M tokens · 50/50 input/output| Volume | Grok 4.5 | Gemini 3.1 Pro | Savings |
|---|---|---|---|
| 1M tokens | $3 | $4.5 | $1.5 (33.3%) |
| 10M tokens | $30 | $45 | $15 (33.3%) |
| 100M tokens | $300 | $450 | $150 (33.3%) |
| 1000M tokens | $3000 | $4500 | $1500 (33.3%) |
When to pick which
distilled from the pricing and spec data above- cost dominates: $3.00/Mtok blended vs $4.50 — 33.3% less on the same 50/50 token mix
- your workload re-reads context (agents, RAG, long chats): cached input costs $0.200/Mtok — 90% off its list input price, a discount Grok 4.5 doesn't offer
- you need the longer context: 2M tokens vs 500K (4×)
The cheaper option here — Grok 4.5 costs $3.00/Mtok blended on xAI.
Summary
Grok 4.5 by xAI costs $2.00/Mtok input and $6.00/Mtok output, with a 500K-token context window. It supports text, image input.
Gemini 3.1 Pro by Google costs $2.00/Mtok input and $12.00/Mtok output, with a 2M-token context window. It supports text, image, audio, video input.
On a blended cost basis, Grok 4.5 is 33.3% cheaper than Gemini 3.1 Pro.
The two aren't directly comparable on average benchmark score: Gemini 3.1 Pro has published per-benchmark results, while Grok 4.5 does not yet — it is measured today on independent composites (see the table above).
Note: Pricing is per million tokens. Actual costs vary with usage patterns, prompt caching, and batch discounts. Always verify against official provider pricing pages.