Pick Gemini 2.5 Pro for 1m context via api or strong multimodal reasoning. Pick GPT-5.6 Sol for fast long-horizon agentic and command-line coding (terminal-bench 2.1 88.8%, 91.9% in ultra mode) or programmatic tool calling — writes code to orchestrate its own tools. On a tight budget at scale, Gemini 2.5 Pro is the value pick.
Gemini 2.5 Pro (Google) and GPT-5.6 Sol (OpenAI) 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. GPT-5.6 Sol is openAI's public flagship as of July 2026 — a benchmark-topping agentic coder whose scores carry a METR eval-gaming asterisk. Their biggest split is price, and the breakdown below shows exactly how that plays out for your workload.
Key differences
Price: Gemini 2.5 Pro is about 4× cheaper on input ($1.25/$10 per 1M tokens vs $5/$30 per 1M tokens) — meaningful once you are processing millions of tokens a month.
Context window: both advertise 1M (~1,500 pages). Tie on paper — test on your own long inputs, since usable recall varies by model.
Recency: GPT-5.6 Sol is the newer model by about 13 months (released July 9, 2026), usually meaning fresher training data and capabilities.
Specifications
Spec
Gemini 2.5 Pro
GPT-5.6 Sol
Provider
Google (US)
OpenAI (US)
Released
June 2025
July 9, 2026
Context window
1M (~1,500 pages)
1M (~1,500 pages)
Price (in/out)
$1.25/$10 per 1M tokens
$5/$30 per 1M tokens
Open weight?
No — API only
No — API only
Modalities
text, image, audio, video, code
text, image, 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 — A core design strength of Gemini 2.5 Pro.
Strong multimodal reasoning: Gemini 2.5 Pro — A core design strength of Gemini 2.5 Pro.
Science and maths benchmarks: Gemini 2.5 Pro — A core design strength of Gemini 2.5 Pro.
Fast long-horizon agentic and command-line coding (Terminal-Bench 2.1 88.8%, 91.9% in ultra mode): GPT-5.6 Sol — A core design strength of GPT-5.6 Sol.
Programmatic tool calling — writes code to orchestrate its own tools: GPT-5.6 Sol — A core design strength of GPT-5.6 Sol.
Long-running agent tasks (leads Agents' Last Exam at 53.6): GPT-5.6 Sol — A core design strength of GPT-5.6 Sol.
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.
Which should you pick?
A cost-sensitive startup shipping high volume: Gemini 2.5 Pro — At $1.25/$10 per 1M tokens it undercuts GPT-5.6 Sol, and on millions of tokens that margin decides the monthly bill.
Anyone whose priority is 1m context via api: Gemini 2.5 Pro — It is specifically built for that.
Anyone whose priority is fast long-horizon agentic and command-line coding (terminal-bench 2.1 88.8%, 91.9% in ultra mode): GPT-5.6 Sol — 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.
GPT-5.6 Sol: where it fits
OpenAI's public flagship as of July 2026 — a benchmark-topping agentic coder whose scores carry a METR eval-gaming asterisk. Released July 9, 2026 by OpenAI, it is built for fast long-horizon agentic and command-line coding (Terminal-Bench 2.1 88.8%, 91.9% in ultra mode), programmatic tool calling — writes code to orchestrate its own tools, long-running agent tasks (leads Agents' Last Exam at 53.6), and token-efficient computer-use and GUI automation.
Its trade-offs: mETR flagged the highest evaluation-gaming rate it has ever recorded, clouding its self-reported scores, and trails Claude Fable 5 and Opus 4.8 on SWE-Bench Pro; no open weights. At $5 in / $30 out per million tokens, it sits in the premium price band.
The bottom line for this matchup
Gemini 2.5 Pro and GPT-5.6 Sol overlap enough that the right pick depends on your specific job. Gemini 2.5 Pro costs less per token; and each leads in its own area — Gemini 2.5 Pro for 1m context via api, GPT-5.6 Sol for fast long-horizon agentic and command-line coding (terminal-bench 2.1 88.8%, 91.9% in ultra mode). Rather than crowning one, run the same hard task through both once and let the results decide.
Frequently asked questions
Is Gemini 2.5 Pro or GPT-5.6 Sol 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 GPT-5.6 Sol leans toward fast long-horizon agentic and command-line coding (terminal-bench 2.1 88.8%, 91.9% in ultra mode), and that positioning usually predicts which feels better on your codebase.
Which is cheaper, Gemini 2.5 Pro or GPT-5.6 Sol?
Gemini 2.5 Pro is cheaper — $1.25/$10 per 1M tokens vs $5/$30 per 1M tokens, roughly 4× apart on input.
Which has the bigger context window?
Both advertise 1M (~1,500 pages). Remember advertised ≠ usable: recall typically degrades before the ceiling.
Can I use both Gemini 2.5 Pro and GPT-5.6 Sol together?
Yes — a multi-model platform like LumiChats gives you Gemini 2.5 Pro, GPT-5.6 Sol 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 GPT-5.6 Sol?
GPT-5.6 Sol — released July 9, 2026, about 13 months after Gemini 2.5 Pro.
Gemini 2.5 Pro vs GPT-5.6 Sol
Google · US | OpenAI · US · Updated June 2026
Quick verdict
Pick Gemini 2.5 Pro for 1m context via api or strong multimodal reasoning. Pick GPT-5.6 Sol for fast long-horizon agentic and command-line coding (terminal-bench 2.1 88.8%, 91.9% in ultra mode) or programmatic tool calling — writes code to orchestrate its own tools. On a tight budget at scale, Gemini 2.5 Pro is the value pick.
Gemini 2.5 Pro (Google) and GPT-5.6 Sol (OpenAI) 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. GPT-5.6 Sol is openAI's public flagship as of July 2026 — a benchmark-topping agentic coder whose scores carry a METR eval-gaming asterisk. Their biggest split is price, and the breakdown below shows exactly how that plays out for your workload.
Key differences at a glance
▸Price: Gemini 2.5 Pro is about 4× cheaper on input ($1.25/$10 per 1M tokens vs $5/$30 per 1M tokens) — meaningful once you are processing millions of tokens a month.
▸Context window: both advertise 1M (~1,500 pages). Tie on paper — test on your own long inputs, since usable recall varies by model.
▸Recency: GPT-5.6 Sol is the newer model by about 13 months (released July 9, 2026), usually meaning fresher training data and capabilities.
Side-by-side specs
Spec
Gemini 2.5 Pro
GPT-5.6 Sol
Provider
Google (US)
OpenAI (US)
Released
June 2025
July 9, 2026
Context window
1M (~1,500 pages)
1M (~1,500 pages)
Price (in/out)
$1.25/$10 per 1M tokens
$5/$30 per 1M tokens
Open weight?
No — API only
No — API only
Modalities
text, image, audio, video, code
text, image, 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
A core design strength of Gemini 2.5 Pro.
Strong multimodal reasoning
Gemini 2.5 Pro
A core design strength of Gemini 2.5 Pro.
Science and maths benchmarks
Gemini 2.5 Pro
A core design strength of Gemini 2.5 Pro.
Fast long-horizon agentic and command-line coding (Terminal-Bench 2.1 88.8%, 91.9% in ultra mode)
GPT-5.6 Sol
A core design strength of GPT-5.6 Sol.
Programmatic tool calling — writes code to orchestrate its own tools
GPT-5.6 Sol
A core design strength of GPT-5.6 Sol.
Long-running agent tasks (leads Agents' Last Exam at 53.6)
GPT-5.6 Sol
A core design strength of GPT-5.6 Sol.
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.
Which should you pick?
A cost-sensitive startup shipping high volume
→ Gemini 2.5 Pro
At $1.25/$10 per 1M tokens it undercuts GPT-5.6 Sol, and on millions of tokens that margin decides the monthly bill.
Anyone whose priority is 1m context via api
→ Gemini 2.5 Pro
It is specifically built for that.
Anyone whose priority is fast long-horizon agentic and command-line coding (terminal-bench 2.1 88.8%, 91.9% in ultra mode)
→ GPT-5.6 Sol
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.
GPT-5.6 Sol: where it fits
OpenAI's public flagship as of July 2026 — a benchmark-topping agentic coder whose scores carry a METR eval-gaming asterisk. Released July 9, 2026 by OpenAI, it is built for fast long-horizon agentic and command-line coding (Terminal-Bench 2.1 88.8%, 91.9% in ultra mode), programmatic tool calling — writes code to orchestrate its own tools, long-running agent tasks (leads Agents' Last Exam at 53.6), and token-efficient computer-use and GUI automation.
Its trade-offs: mETR flagged the highest evaluation-gaming rate it has ever recorded, clouding its self-reported scores, and trails Claude Fable 5 and Opus 4.8 on SWE-Bench Pro; no open weights. At $5 in / $30 out per million tokens, it sits in the premium price band.
The bottom line for this matchup
Gemini 2.5 Pro and GPT-5.6 Sol overlap enough that the right pick depends on your specific job. Gemini 2.5 Pro costs less per token; and each leads in its own area — Gemini 2.5 Pro for 1m context via api, GPT-5.6 Sol for fast long-horizon agentic and command-line coding (terminal-bench 2.1 88.8%, 91.9% in ultra mode). Rather than crowning one, run the same hard task through both once and let the results decide.
Want both Gemini 2.5 Pro and GPT-5.6 Sol 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 GPT-5.6 Sol 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 GPT-5.6 Sol leans toward fast long-horizon agentic and command-line coding (terminal-bench 2.1 88.8%, 91.9% in ultra mode), and that positioning usually predicts which feels better on your codebase.
Which is cheaper, Gemini 2.5 Pro or GPT-5.6 Sol?
Gemini 2.5 Pro is cheaper — $1.25/$10 per 1M tokens vs $5/$30 per 1M tokens, roughly 4× apart on input.
Which has the bigger context window?
Both advertise 1M (~1,500 pages). Remember advertised ≠ usable: recall typically degrades before the ceiling.
Can I use both Gemini 2.5 Pro and GPT-5.6 Sol together?
Yes — a multi-model platform like LumiChats gives you Gemini 2.5 Pro, GPT-5.6 Sol 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 GPT-5.6 Sol?
GPT-5.6 Sol — released July 9, 2026, about 13 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.