Both are Google models. Gemini 3.1 Pro is the newer, generally stronger default; reach for Gemini 2.5 Pro when its lower price or a specific cost or latency profile matters more than the latest capabilities.
Gemini 2.5 Pro and Gemini 3.1 Pro are both Google models, so the real question is not which lab to trust but which tier fits your workload and budget. Gemini 2.5 Pro is google's previous-gen 2M flagship — still a strong long-context multimodal option. Gemini 3.1 Pro is a 2M-token multimodal workhorse — huge breadth, but recall fades deep in the window. Since both come from the same lab, the comparison below focuses on the tier-and-cost trade-offs that actually separate them.
Key differences
Price: Gemini 2.5 Pro is about 1.6× cheaper on input ($1.25/$10 per 1M tokens vs $2/$12 per 1M tokens) — modest, but it adds up at steady volume.
Context window: Gemini 3.1 Pro holds 2× more — 2M (~3,000 pages) vs 1M (~1,500 pages). But effective recall usually fades long before the advertised ceiling, so the bigger number only helps if the model reasons over it.
Recency: Gemini 3.1 Pro is the newer model by about 9 months (released February 19, 2026), usually meaning fresher training data and capabilities.
Specifications
Spec
Gemini 2.5 Pro
Gemini 3.1 Pro
Provider
Google (US)
Google (US)
Released
June 2025
February 19, 2026
Context window
1M (~1,500 pages)
2M (~3,000 pages)
Price (in/out)
$1.25/$10 per 1M tokens
$2/$12 per 1M tokens
Open weight?
No — API only
No — API only
Modalities
text, image, audio, video, code
text, image, audio, video, code
SWE-Bench Verified
Not published
Not published
MRCR v2 @ 1M
Not published
26.3%
Who wins what
1M context via API: Gemini 2.5 Pro — Gemini 3.1 Pro is comparatively weak here — long-context recall drops sharply past 256K
Strong multimodal reasoning: Gemini 2.5 Pro — Google's previous-gen 2M flagship — still a strong long-context multimodal option — and it runs cheaper at $1.25/$10 per 1M tokens.
Science and maths benchmarks: Gemini 2.5 Pro — Gemini 2.5 Pro lists science and maths benchmarks among its strengths; Gemini 3.1 Pro does not.
Largest mainstream production context (2M): Gemini 3.1 Pro — Its 2M window holds about 2× more than Gemini 2.5 Pro's 1M in a single prompt.
Long video and document analysis: Gemini 3.1 Pro — A 2M-token multimodal workhorse — huge breadth, but recall fades deep in the window — and it carries the larger 2M context.
Agentic reasoning (high ARC-AGI-2): Gemini 3.1 Pro — A 2M-token multimodal workhorse — huge breadth, but recall fades deep in the window — and it is the newer of the two.
Lowest cost at scale: Gemini 2.5 Pro — At $1.25/$10 per 1M tokens, it is the cheaper of the two — the gap dominates the bill on high-volume workloads.
Largest single-prompt input: Gemini 3.1 Pro — Its 2M window is about 2× larger than Gemini 2.5 Pro's 1M, fitting roughly 3,000 pages in one prompt.
Which should you pick?
A cost-sensitive startup shipping high volume: Gemini 2.5 Pro — At $1.25/$10 per 1M tokens it undercuts Gemini 3.1 Pro, and on millions of tokens that margin decides the monthly bill.
Someone analysing very long documents or codebases: Gemini 3.1 Pro — Larger 2M 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 largest mainstream production context (2m): Gemini 3.1 Pro — 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.
Gemini 3.1 Pro: where it fits
A 2M-token multimodal workhorse — huge breadth, but recall fades deep in the window. Released February 19, 2026 by Google, it is built for largest mainstream production context (2M), long video and document analysis, agentic reasoning (high ARC-AGI-2), and multimodal understanding.
Its trade-offs: long-context recall drops sharply past 256K, and premium price per token. At $2 in / $12 out per million tokens, it sits in the mid price band.
The bottom line for this matchup
Because Gemini 2.5 Pro and Gemini 3.1 Pro come from the same lab (Google), they share the same training philosophy and ecosystem — the decision is purely tier vs. cost. Gemini 3.1 Pro is the more capable, more recent option; the other earns its place only when its price or latency profile fits a specific job better. Most teams should default to Gemini 3.1 Pro and drop down only with a concrete reason.
Frequently asked questions
Is Gemini 2.5 Pro or Gemini 3.1 Pro 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 Gemini 3.1 Pro leans toward largest mainstream production context (2m), and that positioning usually predicts which feels better on your codebase.
Which is cheaper, Gemini 2.5 Pro or Gemini 3.1 Pro?
Gemini 2.5 Pro is cheaper — $1.25/$10 per 1M tokens vs $2/$12 per 1M tokens, roughly 1.6× apart on input.
Which has the bigger context window?
Gemini 3.1 Pro — 2M vs 1M, about 2× larger. Useful only if the model actually reasons over the full window, which not all do.
Should I upgrade from Gemini 2.5 Pro to Gemini 3.1 Pro?
Since both are Google models, the newer one (Gemini 3.1 Pro) is usually the better default unless you need a specific cost or latency profile from the other.
Which is newer, Gemini 2.5 Pro or Gemini 3.1 Pro?
Gemini 3.1 Pro — released February 19, 2026, about 9 months after Gemini 2.5 Pro.
Gemini 2.5 Pro vs Gemini 3.1 Pro
Google · US | Google · US · Updated June 2026
Quick verdict
Both are Google models. Gemini 3.1 Pro is the newer, generally stronger default; reach for Gemini 2.5 Pro when its lower price or a specific cost or latency profile matters more than the latest capabilities.
Gemini 2.5 Pro and Gemini 3.1 Pro are both Google models, so the real question is not which lab to trust but which tier fits your workload and budget. Gemini 2.5 Pro is google's previous-gen 2M flagship — still a strong long-context multimodal option. Gemini 3.1 Pro is a 2M-token multimodal workhorse — huge breadth, but recall fades deep in the window. Since both come from the same lab, the comparison below focuses on the tier-and-cost trade-offs that actually separate them.
Key differences at a glance
▸Price: Gemini 2.5 Pro is about 1.6× cheaper on input ($1.25/$10 per 1M tokens vs $2/$12 per 1M tokens) — modest, but it adds up at steady volume.
▸Context window: Gemini 3.1 Pro holds 2× more — 2M (~3,000 pages) vs 1M (~1,500 pages). But effective recall usually fades long before the advertised ceiling, so the bigger number only helps if the model reasons over it.
▸Recency: Gemini 3.1 Pro is the newer model by about 9 months (released February 19, 2026), usually meaning fresher training data and capabilities.
Side-by-side specs
Spec
Gemini 2.5 Pro
Gemini 3.1 Pro
Provider
Google (US)
Google (US)
Released
June 2025
February 19, 2026
Context window
1M (~1,500 pages)
2M (~3,000 pages)
Price (in/out)
$1.25/$10 per 1M tokens
$2/$12 per 1M tokens
Open weight?
No — API only
No — API only
Modalities
text, image, audio, video, code
text, image, audio, video, code
SWE-Bench Verified
Not published
Not published
MRCR v2 @ 1M
Not published
26.3%
Who wins what
1M context via API
Gemini 2.5 Pro
Gemini 3.1 Pro is comparatively weak here — long-context recall drops sharply past 256K
Strong multimodal reasoning
Gemini 2.5 Pro
Google's previous-gen 2M flagship — still a strong long-context multimodal option — and it runs cheaper at $1.25/$10 per 1M tokens.
Science and maths benchmarks
Gemini 2.5 Pro
Gemini 2.5 Pro lists science and maths benchmarks among its strengths; Gemini 3.1 Pro does not.
Largest mainstream production context (2M)
Gemini 3.1 Pro
Its 2M window holds about 2× more than Gemini 2.5 Pro's 1M in a single prompt.
Long video and document analysis
Gemini 3.1 Pro
A 2M-token multimodal workhorse — huge breadth, but recall fades deep in the window — and it carries the larger 2M context.
Agentic reasoning (high ARC-AGI-2)
Gemini 3.1 Pro
A 2M-token multimodal workhorse — huge breadth, but recall fades deep in the window — and it is the newer of the two.
Lowest cost at scale
Gemini 2.5 Pro
At $1.25/$10 per 1M tokens, it is the cheaper of the two — the gap dominates the bill on high-volume workloads.
Largest single-prompt input
Gemini 3.1 Pro
Its 2M window is about 2× larger than Gemini 2.5 Pro's 1M, fitting roughly 3,000 pages in one prompt.
Which should you pick?
A cost-sensitive startup shipping high volume
→ Gemini 2.5 Pro
At $1.25/$10 per 1M tokens it undercuts Gemini 3.1 Pro, and on millions of tokens that margin decides the monthly bill.
Someone analysing very long documents or codebases
→ Gemini 3.1 Pro
Larger 2M 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 largest mainstream production context (2m)
→ Gemini 3.1 Pro
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.
Gemini 3.1 Pro: where it fits
A 2M-token multimodal workhorse — huge breadth, but recall fades deep in the window. Released February 19, 2026 by Google, it is built for largest mainstream production context (2M), long video and document analysis, agentic reasoning (high ARC-AGI-2), and multimodal understanding.
Its trade-offs: long-context recall drops sharply past 256K, and premium price per token. At $2 in / $12 out per million tokens, it sits in the mid price band.
The bottom line for this matchup
Because Gemini 2.5 Pro and Gemini 3.1 Pro come from the same lab (Google), they share the same training philosophy and ecosystem — the decision is purely tier vs. cost. Gemini 3.1 Pro is the more capable, more recent option; the other earns its place only when its price or latency profile fits a specific job better. Most teams should default to Gemini 3.1 Pro and drop down only with a concrete reason.
Want both Gemini 2.5 Pro and Gemini 3.1 Pro 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.
Is Gemini 2.5 Pro or Gemini 3.1 Pro 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 Gemini 3.1 Pro leans toward largest mainstream production context (2m), and that positioning usually predicts which feels better on your codebase.
Which is cheaper, Gemini 2.5 Pro or Gemini 3.1 Pro?
Gemini 2.5 Pro is cheaper — $1.25/$10 per 1M tokens vs $2/$12 per 1M tokens, roughly 1.6× apart on input.
Which has the bigger context window?
Gemini 3.1 Pro — 2M vs 1M, about 2× larger. Useful only if the model actually reasons over the full window, which not all do.
Should I upgrade from Gemini 2.5 Pro to Gemini 3.1 Pro?
Since both are Google models, the newer one (Gemini 3.1 Pro) is usually the better default unless you need a specific cost or latency profile from the other.
Which is newer, Gemini 2.5 Pro or Gemini 3.1 Pro?
Gemini 3.1 Pro — released February 19, 2026, about 9 months after Gemini 2.5 Pro.
Specifications and benchmarks reflect publicly reported figures as of June 2026 and may change as providers release updates. Always verify on your own workload.