Pick Claude Sonnet 4.5 for agentic coding — 77.2% on swe-bench verified, the best score any model had posted at its launch or computer use and gui automation (61.4% osworld at launch). Pick Gemini 3.1 Pro for largest mainstream production context (2m) or long video and document analysis. On a tight budget at scale, Gemini 3.1 Pro is the value pick.
Claude Sonnet 4.5 (Anthropic) and Gemini 3.1 Pro (Google) are two of the models people most often weigh against each other in 2026. Claude Sonnet 4.5 is september 2025's coding state of the art at $3/$15 — still supported, but 200K-capped and twice superseded. Gemini 3.1 Pro is a 2M-token multimodal workhorse — huge breadth, but recall fades deep in the window. They diverge most on price and context window — each quantified below from the models' real specs.
Key differences
Price: Gemini 3.1 Pro is about 1.5× cheaper on input ($2/$12 per 1M tokens vs $3/$15 per 1M tokens) — modest, but it adds up at steady volume.
Context window: Gemini 3.1 Pro holds 10× more — 2M (~3,000 pages) vs 200K (~300 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 5 months (released February 19, 2026), usually meaning fresher training data and capabilities.
Specifications
Spec
Claude Sonnet 4.5
Gemini 3.1 Pro
Provider
Anthropic (US)
Google (US)
Released
September 29, 2025
February 19, 2026
Context window
200K (~300 pages)
2M (~3,000 pages)
Price (in/out)
$3/$15 per 1M tokens
$2/$12 per 1M tokens
Open weight?
No — API only
No — API only
Modalities
text, image, code
text, image, audio, video, code
SWE-Bench Verified
77.2%
Not published
MRCR v2 @ 1M
Not published
26.3%
Who wins what
Agentic coding — 77.2% on SWE-Bench Verified, the best score any model had posted at its launch: Claude Sonnet 4.5 — Claude Sonnet 4.5 lists agentic coding — 77.2% on SWE-Bench Verified, the best score any model had posted at its launch among its strengths; Gemini 3.1 Pro does not.
Computer use and GUI automation (61.4% OSWorld at launch): Claude Sonnet 4.5 — Claude Sonnet 4.5 lists computer use and GUI automation (61.4% OSWorld at launch) among its strengths; Gemini 3.1 Pro does not.
Long-horizon autonomy — Anthropic reported 30+ hours of sustained focus on multi-step tasks: Claude Sonnet 4.5 — Claude Sonnet 4.5 lists long-horizon autonomy — Anthropic reported 30+ hours of sustained focus on multi-step tasks among its strengths; Gemini 3.1 Pro does not.
Largest mainstream production context (2M): Gemini 3.1 Pro — Its 2M window holds about 10× more than Claude Sonnet 4.5's 200K 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 runs cheaper at $2/$12 per 1M tokens.
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 carries the larger 2M context.
Lowest cost at scale: Gemini 3.1 Pro — At $2/$12 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 10× larger than Claude Sonnet 4.5's 200K, fitting roughly 3,000 pages in one prompt.
Which should you pick?
A cost-sensitive startup shipping high volume: Gemini 3.1 Pro — At $2/$12 per 1M tokens it undercuts Claude Sonnet 4.5, 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 agentic coding — 77.2% on swe-bench verified, the best score any model had posted at its launch: Claude Sonnet 4.5 — It is specifically built for that.
Anyone whose priority is largest mainstream production context (2m): Gemini 3.1 Pro — That is its strongest area.
Claude Sonnet 4.5: where it fits
September 2025's coding state of the art at $3/$15 — still supported, but 200K-capped and twice superseded. Released September 29, 2025 by Anthropic, it is built for agentic coding — 77.2% on SWE-Bench Verified, the best score any model had posted at its launch, computer use and GUI automation (61.4% OSWorld at launch), long-horizon autonomy — Anthropic reported 30+ hours of sustained focus on multi-step tasks, and tracking its own remaining token budget natively, which few models do.
Its trade-offs are real: superseded twice — Sonnet 4.6 and Sonnet 5 match or beat it at the same or lower price, capped at 200K since Anthropic retired its 1M beta in April 2026, while its successors ship 1M as standard, and missing the modern API surface: no adaptive thinking, no effort control, and half the max output of newer Sonnets. At $3 in / $15 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
Claude Sonnet 4.5 and Gemini 3.1 Pro overlap enough that the right pick depends on your specific job. Gemini 3.1 Pro costs less per token; Gemini 3.1 Pro holds the larger context; and each leads in its own area — Claude Sonnet 4.5 for agentic coding — 77.2% on swe-bench verified, the best score any model had posted at its launch, Gemini 3.1 Pro for largest mainstream production context (2m). Rather than crowning one, run the same hard task through both once and let the results decide.
Frequently asked questions
Is Claude Sonnet 4.5 or Gemini 3.1 Pro better for coding?
Public SWE-Bench figures are not available for Gemini 3.1 Pro, so the honest test is your own repository — run an identical real bug through both. By design, Claude Sonnet 4.5 leans toward agentic coding — 77.2% on swe-bench verified, the best score any model had posted at its launch 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, Claude Sonnet 4.5 or Gemini 3.1 Pro?
Gemini 3.1 Pro is cheaper — $3/$15 per 1M tokens vs $2/$12 per 1M tokens, roughly 1.5× apart on input.
Which has the bigger context window?
Gemini 3.1 Pro — 2M vs 200K, about 10× larger. Useful only if the model actually reasons over the full window, which not all do.
Can I use both Claude Sonnet 4.5 and Gemini 3.1 Pro together?
Yes — a multi-model platform like LumiChats gives you Claude Sonnet 4.5, Gemini 3.1 Pro 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, Claude Sonnet 4.5 or Gemini 3.1 Pro?
Gemini 3.1 Pro — released February 19, 2026, about 5 months after Claude Sonnet 4.5.
Claude Sonnet 4.5 vs Gemini 3.1 Pro
Anthropic · US | Google · US · Updated June 2026
Quick verdict
Pick Claude Sonnet 4.5 for agentic coding — 77.2% on swe-bench verified, the best score any model had posted at its launch or computer use and gui automation (61.4% osworld at launch). Pick Gemini 3.1 Pro for largest mainstream production context (2m) or long video and document analysis. On a tight budget at scale, Gemini 3.1 Pro is the value pick.
Claude Sonnet 4.5 (Anthropic) and Gemini 3.1 Pro (Google) are two of the models people most often weigh against each other in 2026. Claude Sonnet 4.5 is september 2025's coding state of the art at $3/$15 — still supported, but 200K-capped and twice superseded. Gemini 3.1 Pro is a 2M-token multimodal workhorse — huge breadth, but recall fades deep in the window. They diverge most on price and context window — each quantified below from the models' real specs.
Key differences at a glance
▸Price: Gemini 3.1 Pro is about 1.5× cheaper on input ($2/$12 per 1M tokens vs $3/$15 per 1M tokens) — modest, but it adds up at steady volume.
▸Context window: Gemini 3.1 Pro holds 10× more — 2M (~3,000 pages) vs 200K (~300 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 5 months (released February 19, 2026), usually meaning fresher training data and capabilities.
Side-by-side specs
Spec
Claude Sonnet 4.5
Gemini 3.1 Pro
Provider
Anthropic (US)
Google (US)
Released
September 29, 2025
February 19, 2026
Context window
200K (~300 pages)
2M (~3,000 pages)
Price (in/out)
$3/$15 per 1M tokens
$2/$12 per 1M tokens
Open weight?
No — API only
No — API only
Modalities
text, image, code
text, image, audio, video, code
SWE-Bench Verified
77.2%
Not published
MRCR v2 @ 1M
Not published
26.3%
Who wins what
Agentic coding — 77.2% on SWE-Bench Verified, the best score any model had posted at its launch
Claude Sonnet 4.5
Claude Sonnet 4.5 lists agentic coding — 77.2% on SWE-Bench Verified, the best score any model had posted at its launch among its strengths; Gemini 3.1 Pro does not.
Computer use and GUI automation (61.4% OSWorld at launch)
Claude Sonnet 4.5
Claude Sonnet 4.5 lists computer use and GUI automation (61.4% OSWorld at launch) among its strengths; Gemini 3.1 Pro does not.
Long-horizon autonomy — Anthropic reported 30+ hours of sustained focus on multi-step tasks
Claude Sonnet 4.5
Claude Sonnet 4.5 lists long-horizon autonomy — Anthropic reported 30+ hours of sustained focus on multi-step tasks among its strengths; Gemini 3.1 Pro does not.
Largest mainstream production context (2M)
Gemini 3.1 Pro
Its 2M window holds about 10× more than Claude Sonnet 4.5's 200K 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 runs cheaper at $2/$12 per 1M tokens.
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 carries the larger 2M context.
Lowest cost at scale
Gemini 3.1 Pro
At $2/$12 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 10× larger than Claude Sonnet 4.5's 200K, fitting roughly 3,000 pages in one prompt.
Which should you pick?
A cost-sensitive startup shipping high volume
→ Gemini 3.1 Pro
At $2/$12 per 1M tokens it undercuts Claude Sonnet 4.5, 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 agentic coding — 77.2% on swe-bench verified, the best score any model had posted at its launch
→ Claude Sonnet 4.5
It is specifically built for that.
Anyone whose priority is largest mainstream production context (2m)
→ Gemini 3.1 Pro
That is its strongest area.
Claude Sonnet 4.5: where it fits
September 2025's coding state of the art at $3/$15 — still supported, but 200K-capped and twice superseded. Released September 29, 2025 by Anthropic, it is built for agentic coding — 77.2% on SWE-Bench Verified, the best score any model had posted at its launch, computer use and GUI automation (61.4% OSWorld at launch), long-horizon autonomy — Anthropic reported 30+ hours of sustained focus on multi-step tasks, and tracking its own remaining token budget natively, which few models do.
Its trade-offs are real: superseded twice — Sonnet 4.6 and Sonnet 5 match or beat it at the same or lower price, capped at 200K since Anthropic retired its 1M beta in April 2026, while its successors ship 1M as standard, and missing the modern API surface: no adaptive thinking, no effort control, and half the max output of newer Sonnets. At $3 in / $15 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
Claude Sonnet 4.5 and Gemini 3.1 Pro overlap enough that the right pick depends on your specific job. Gemini 3.1 Pro costs less per token; Gemini 3.1 Pro holds the larger context; and each leads in its own area — Claude Sonnet 4.5 for agentic coding — 77.2% on swe-bench verified, the best score any model had posted at its launch, Gemini 3.1 Pro for largest mainstream production context (2m). Rather than crowning one, run the same hard task through both once and let the results decide.
Want both Claude Sonnet 4.5 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 Claude Sonnet 4.5 or Gemini 3.1 Pro better for coding?
Public SWE-Bench figures are not available for Gemini 3.1 Pro, so the honest test is your own repository — run an identical real bug through both. By design, Claude Sonnet 4.5 leans toward agentic coding — 77.2% on swe-bench verified, the best score any model had posted at its launch 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, Claude Sonnet 4.5 or Gemini 3.1 Pro?
Gemini 3.1 Pro is cheaper — $3/$15 per 1M tokens vs $2/$12 per 1M tokens, roughly 1.5× apart on input.
Which has the bigger context window?
Gemini 3.1 Pro — 2M vs 200K, about 10× larger. Useful only if the model actually reasons over the full window, which not all do.
Can I use both Claude Sonnet 4.5 and Gemini 3.1 Pro together?
Yes — a multi-model platform like LumiChats gives you Claude Sonnet 4.5, Gemini 3.1 Pro 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, Claude Sonnet 4.5 or Gemini 3.1 Pro?
Gemini 3.1 Pro — released February 19, 2026, about 5 months after Claude Sonnet 4.5.
Specifications and benchmarks reflect publicly reported figures as of June 2026 and may change as providers release updates. Always verify on your own workload.