Gemini 4 Argon vs GPT-5.6 Terra
Google · US | OpenAI · US · Updated June 2026
Quick verdict
Pick Gemini 4 Argon for 1,048,576-token unified context shared by input, thinking and output, with 'long decode' for very long responses or google-reported deepswe v1.1 of 77.9% and lvbench long-video understanding of 91.7%. Pick GPT-5.6 Terra for balanced everyday work at roughly half of sol's price or competitive with gpt-5.5 quality at about 2x lower cost. On a tight budget at scale, Gemini 4 Argon is the value pick.
Gemini 4 Argon (Google) and GPT-5.6 Terra (OpenAI) are two of the models people most often weigh against each other in 2026. Gemini 4 Argon is google's Gemini 4 Argon, broadly available October 13, 2026 - a 1M-context model at $2/$10 introductory pricing (doubling December 1). GPT-5.6 Terra is the mid-tier daily driver of the GPT-5.6 family — near-flagship quality at about half of Sol's cost. They diverge most on price and context window — each quantified below from the models' real specs.
Key differences at a glance
- ▸Price: nearly identical — $2/$10 per 1M tokens vs $2.5/$15 per 1M tokens. Cost will not be the deciding factor here.
- ▸Context window: 1M tokens vs 1M — within a few percent of each other, so treat this as a tie and test on your own long inputs, since usable recall varies by model.
- ▸Recency: Gemini 4 Argon is the newer model by about 3 months (released October 13, 2026), usually meaning fresher training data and capabilities.
Side-by-side specs
| Spec | Gemini 4 Argon | GPT-5.6 Terra |
|---|---|---|
| Provider | Google (US) | OpenAI (US) |
| Released | October 13, 2026 | July 9, 2026 |
| Context window | 1M tokens (~1,573 pages) | 1M (~1,500 pages) |
| Price (in/out) | $2/$10 per 1M tokens | $2.5/$15 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
1,048,576-token unified context shared by input, thinking and output, with 'long decode' for very long responses
Gemini 4 Argon
Google's Gemini 4 Argon, broadly available October 13, 2026 - a 1M-context model at $2/$10 introductory pricing (doubling December 1) — and it runs cheaper at $2/$10 per 1M tokens.
Google-reported DeepSWE v1.1 of 77.9% and LVBench long-video understanding of 91.7%
Gemini 4 Argon
Google's Gemini 4 Argon, broadly available October 13, 2026 - a 1M-context model at $2/$10 introductory pricing (doubling December 1) — and it is the newer of the two.
Artificial Analysis Intelligence Index of 53 at high effort (AI Weekly)
Gemini 4 Argon
Gemini 4 Argon lists artificial Analysis Intelligence Index of 53 at high effort (AI Weekly) among its strengths; GPT-5.6 Terra does not.
Balanced everyday work at roughly half of Sol's price
GPT-5.6 Terra
GPT-5.6 Terra lists balanced everyday work at roughly half of Sol's price among its strengths; Gemini 4 Argon does not.
Competitive with GPT-5.5 quality at about 2x lower cost
GPT-5.6 Terra
Gemini 4 Argon is comparatively weak here — verbose: about 62K output tokens per Artificial Analysis task, so cost per task is high
Solid agentic coding (Terminal-Bench 2.1 in the mid-80s)
GPT-5.6 Terra
GPT-5.6 Terra lists solid agentic coding (Terminal-Bench 2.1 in the mid-80s) among its strengths; Gemini 4 Argon does not.
Lowest cost at scale
Gemini 4 Argon
At $2/$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 4 Argon
At $2/$10 per 1M tokens it undercuts GPT-5.6 Terra, and on millions of tokens that margin decides the monthly bill.
Someone analysing very long documents or codebases
→ Gemini 4 Argon
Larger 1M tokens window fits more in one prompt.
Anyone whose priority is 1,048,576-token unified context shared by input, thinking and output, with 'long decode' for very long responses
→ Gemini 4 Argon
It is specifically built for that.
Anyone whose priority is balanced everyday work at roughly half of sol's price
→ GPT-5.6 Terra
That is its strongest area.
Gemini 4 Argon: where it fits
Google's Gemini 4 Argon, broadly available October 13, 2026 - a 1M-context model at $2/$10 introductory pricing (doubling December 1). Released October 13, 2026 by Google, it is built for 1,048,576-token unified context shared by input, thinking and output, with 'long decode' for very long responses, google-reported DeepSWE v1.1 of 77.9% and LVBench long-video understanding of 91.7%, and artificial Analysis Intelligence Index of 53 at high effort (AI Weekly).
Its trade-offs are real: introductory $2/$10 pricing ends November 30; from December 1 it doubles to $4/$20, verbose: about 62K output tokens per Artificial Analysis task, so cost per task is high, and announced September 30 for trusted cyber defenders only; broad paid-tier availability followed October 13 (not on the free tier). At $2 in / $10 out per million tokens, it sits in the mid price band.
GPT-5.6 Terra: where it fits
The mid-tier daily driver of the GPT-5.6 family — near-flagship quality at about half of Sol's cost. Released July 9, 2026 by OpenAI, it is built for balanced everyday work at roughly half of Sol's price, competitive with GPT-5.5 quality at about 2x lower cost, solid agentic coding (Terminal-Bench 2.1 in the mid-80s), and same 1M context and programmatic tool calling as Sol.
Its trade-offs: fewer independently verified benchmarks than Sol, and trails it across coding evals, and no open weights. At $2.5 in / $15 out per million tokens, it sits in the mid price band.
The bottom line for this matchup
Gemini 4 Argon and GPT-5.6 Terra overlap enough that the right pick depends on your specific job. Gemini 4 Argon costs less per token; Gemini 4 Argon holds the larger context; and each leads in its own area — Gemini 4 Argon for 1,048,576-token unified context shared by input, thinking and output, with 'long decode' for very long responses, GPT-5.6 Terra for balanced everyday work at roughly half of sol's price. Rather than crowning one, run the same hard task through both once and let the results decide.
Want both Gemini 4 Argon and GPT-5.6 Terra 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 4 Argon or GPT-5.6 Terra 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 4 Argon leans toward 1,048,576-token unified context shared by input, thinking and output, with 'long decode' for very long responses while GPT-5.6 Terra leans toward balanced everyday work at roughly half of sol's price, and that positioning usually predicts which feels better on your codebase.
Which is cheaper, Gemini 4 Argon or GPT-5.6 Terra?
Gemini 4 Argon is cheaper — $2/$10 per 1M tokens vs $2.5/$15 per 1M tokens, roughly 1.3× apart on input.
Which has the bigger context window?
Effectively neither — 1M tokens vs 1M is a difference of a few percent. Remember advertised ≠ usable: recall typically degrades before the ceiling.
Can I use both Gemini 4 Argon and GPT-5.6 Terra together?
Yes — a multi-model platform like LumiChats gives you Gemini 4 Argon, GPT-5.6 Terra 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 4 Argon or GPT-5.6 Terra?
Gemini 4 Argon — released October 13, 2026, about 3 months after GPT-5.6 Terra.
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.