Gemini 2.5 Pro vs Grok Code Fast 1
Google · US | xAI · US · Updated June 2026
Quick verdict
Pick Gemini 2.5 Pro for 1m context via api or strong multimodal reasoning. Pick Grok Code Fast 1 for fast, cheap agentic coding at $0.20/$1.50 or low-latency code generation and terminal tasks. On a tight budget at scale, Grok Code Fast 1 is the value pick.
Gemini 2.5 Pro (Google) and Grok Code Fast 1 (xAI) are two of the models people most often weigh against each other in 2026. Gemini 2.5 Pro is google's previous-gen 2M flagship — still a strong long-context multimodal option. Grok Code Fast 1 is xAI's speed-tier coding model at $0.20/$1.50 with a 256K window — cheap, fast agentic code over frontier quality. They diverge most on price and context window — each quantified below from the models' real specs.
Key differences at a glance
- ▸Price: Grok Code Fast 1 is about 6.3× cheaper on input ($0.2/$1.5 per 1M tokens vs $1.25/$10 per 1M tokens) — a large enough gap that at scale it can be the single biggest line item in the decision.
- ▸Context window: Gemini 2.5 Pro holds 3.9× more — 1M (~1,500 pages) vs 256K (~384 pages). But effective recall usually fades long before the advertised ceiling, so the bigger number only helps if the model reasons over it.
- ▸Recency: Grok Code Fast 1 is the newer model by about 3 months (released August 28, 2025), usually meaning fresher training data and capabilities.
Side-by-side specs
| Spec | Gemini 2.5 Pro | Grok Code Fast 1 |
|---|---|---|
| Provider | Google (US) | xAI (US) |
| Released | June 2025 | August 28, 2025 |
| Context window | 1M (~1,500 pages) | 256K (~384 pages) |
| Price (in/out) | $1.25/$10 per 1M tokens | $0.2/$1.5 per 1M tokens |
| Open weight? | No — API only | No — API only |
| Modalities | text, image, audio, video, code | text, code |
| SWE-Bench Verified | Not published | Not published |
| MRCR v2 @ 1M | Not published | Not published |
Who wins what
1M context via API
Gemini 2.5 Pro
Its 1M window holds about 3.9× more than Grok Code Fast 1's 256K in a single prompt.
Strong multimodal reasoning
Gemini 2.5 Pro
Google's previous-gen 2M flagship — still a strong long-context multimodal option — and it carries the larger 1M context.
Science and maths benchmarks
Gemini 2.5 Pro
Gemini 2.5 Pro lists science and maths benchmarks among its strengths; Grok Code Fast 1 does not.
Fast, cheap agentic coding at $0.20/$1.50
Grok Code Fast 1
At $0.2/$1.5 per 1M tokens it undercuts Gemini 2.5 Pro ($1.25/$10 per 1M tokens), and that gap compounds at volume.
Low-latency code generation and terminal tasks
Grok Code Fast 1
XAI's speed-tier coding model at $0.20/$1.50 with a 256K window — cheap, fast agentic code over frontier quality — and it runs cheaper at $0.2/$1.5 per 1M tokens.
High-volume coding pipelines where speed beats peak quality
Grok Code Fast 1
XAI's speed-tier coding model at $0.20/$1.50 with a 256K window — cheap, fast agentic code over frontier quality — and it is the newer of the two.
Lowest cost at scale
Grok Code Fast 1
At $0.2/$1.5 per 1M tokens, it is the cheaper of the two — the gap dominates the bill on high-volume workloads.
Largest single-prompt input
Gemini 2.5 Pro
Its 1M window is about 3.9× larger than Grok Code Fast 1's 256K, fitting roughly 1,500 pages in one prompt.
Which should you pick?
A cost-sensitive startup shipping high volume
→ Grok Code Fast 1
At $0.2/$1.5 per 1M tokens it undercuts Gemini 2.5 Pro, and on millions of tokens that margin decides the monthly bill.
Someone analysing very long documents or codebases
→ Gemini 2.5 Pro
Larger 1M window fits more in one prompt.
Anyone whose priority is 1m context via api
→ Gemini 2.5 Pro
It is specifically built for that.
Anyone whose priority is fast, cheap agentic coding at $0.20/$1.50
→ Grok Code Fast 1
That is its strongest area.
Gemini 2.5 Pro: where it fits
Google's previous-gen 2M flagship — still a strong long-context multimodal option. Released June 2025 by Google, it is built for 1M context via API, strong multimodal reasoning, science and maths benchmarks, and whole-book and video analysis.
Its trade-offs are real: superseded by 3.x for newest features, and recall degrades on very long inputs. At $1.25 in / $10 out per million tokens, it sits in the mid price band.
Grok Code Fast 1: where it fits
XAI's speed-tier coding model at $0.20/$1.50 with a 256K window — cheap, fast agentic code over frontier quality. Released August 28, 2025 by xAI, it is built for fast, cheap agentic coding at $0.20/$1.50, low-latency code generation and terminal tasks, high-volume coding pipelines where speed beats peak quality, and a 256K window sized for real codebases.
Its trade-offs: text and code only — no image, audio or video input, xAI did not publish a SWE-Bench Verified score, a speed-tier coding model, not a frontier reasoner, and narrow focus — built for code, not general knowledge work. At $0.2 in / $1.5 out per million tokens, it sits in the budget price band.
The bottom line for this matchup
Gemini 2.5 Pro and Grok Code Fast 1 overlap enough that the right pick depends on your specific job. Grok Code Fast 1 costs less per token; Gemini 2.5 Pro holds the larger context; and each leads in its own area — Gemini 2.5 Pro for 1m context via api, Grok Code Fast 1 for fast, cheap agentic coding at $0.20/$1.50. Rather than crowning one, run the same hard task through both once and let the results decide.
Want both Gemini 2.5 Pro and Grok Code Fast 1 without two subscriptions? LumiChats gives you these plus 40+ models under one ₹69/day pass (about $1/day) — draft with one, cross-check with the other.
See pricingFrequently asked questions
Is Gemini 2.5 Pro or Grok Code Fast 1 better for coding?
Public SWE-Bench figures are not available for either model, so the honest test is your own repository — run an identical real bug through both. By design, Gemini 2.5 Pro leans toward 1m context via api while Grok Code Fast 1 leans toward fast, cheap agentic coding at $0.20/$1.50, and that positioning usually predicts which feels better on your codebase.
Which is cheaper, Gemini 2.5 Pro or Grok Code Fast 1?
Grok Code Fast 1 is cheaper — $1.25/$10 per 1M tokens vs $0.2/$1.5 per 1M tokens, roughly 6.3× apart on input.
Which has the bigger context window?
Gemini 2.5 Pro — 1M vs 256K, about 3.9× larger. Useful only if the model actually reasons over the full window, which not all do.
Can I use both Gemini 2.5 Pro and Grok Code Fast 1 together?
Yes — a multi-model platform like LumiChats gives you Gemini 2.5 Pro, Grok Code Fast 1 and 40+ others under one ₹69/day pass (about $1/day), so you can draft with one and cross-check with the other instead of buying two subscriptions.
Which is newer, Gemini 2.5 Pro or Grok Code Fast 1?
Grok Code Fast 1 — released August 28, 2025, about 3 months after Gemini 2.5 Pro.
Related comparisons
Specifications and benchmarks reflect publicly reported figures as of June 2026 and may change as providers release updates. Always verify on your own workload.