Gemini 3.5 Flash-Lite vs GPT-6.1 Sol
Google · US | OpenAI · US · Updated June 2026
Quick verdict
Pick Gemini 3.5 Flash-Lite for the cheapest gemini tier at $0.30/$2.50 — built for the highest-volume, lowest-margin work or simple classification, extraction and routing where flagship reasoning is wasted spend. Pick GPT-6.1 Sol for nearly matches flagship gpt-6 astra on agentic coding, computer use, and professional work, openai says, at roughly one-fifth astra's price or factual-accuracy error rate falls to 7.7% at low reasoning effort, down from gpt-6 sol's 11.4%. On a tight budget at scale, Gemini 3.5 Flash-Lite is the value pick.
Gemini 3.5 Flash-Lite (Google) and GPT-6.1 Sol (OpenAI) are two of the models people most often weigh against each other in 2026. Gemini 3.5 Flash-Lite is google's cheapest July 2026 model at $0.30/$2.50 — a high-volume, low-cost Lite tier for simple work, not frontier reasoning. GPT-6.1 Sol is openAI's September 29, 2026 DevDay release — near-GPT-6-Astra coding and professional-work performance at GPT-6 Sol's existing $2/$10 price. They diverge most on price and context window — each quantified below from the models' real specs.
Key differences at a glance
- ▸Price: Gemini 3.5 Flash-Lite is about 6.7× cheaper on input ($0.3/$2.5 per 1M tokens vs $2/$10 per 1M tokens) — a large enough gap that at scale it can be the single biggest line item in the decision.
- ▸Context window: 1M vs 1.05M tokens — 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: GPT-6.1 Sol is the newer model by about 2 months (released September 29, 2026), usually meaning fresher training data and capabilities.
Side-by-side specs
| Spec | Gemini 3.5 Flash-Lite | GPT-6.1 Sol |
|---|---|---|
| Provider | Google (US) | OpenAI (US) |
| Released | July 21, 2026 | September 29, 2026 |
| Context window | 1M (~1,500 pages) | 1.05M tokens (~1,575 pages) |
| Price (in/out) | $0.3/$2.5 per 1M tokens | $2/$10 per 1M tokens |
| Open weight? | No — API only | No — API only |
| Modalities | text, image, code | text, image |
| SWE-Bench Verified | Not published | Not published |
| MRCR v2 @ 1M | Not published | Not published |
Who wins what
The cheapest Gemini tier at $0.30/$2.50 — built for the highest-volume, lowest-margin work
Gemini 3.5 Flash-Lite
At $0.3/$2.5 per 1M tokens it undercuts GPT-6.1 Sol ($2/$10 per 1M tokens), and that gap compounds at volume.
Simple classification, extraction and routing where flagship reasoning is wasted spend
Gemini 3.5 Flash-Lite
Google's cheapest July 2026 model at $0.30/$2.50 — a high-volume, low-cost Lite tier for simple work, not frontier reasoning — and it runs cheaper at $0.3/$2.5 per 1M tokens.
Latency-sensitive pipelines that call a model on every request
Gemini 3.5 Flash-Lite
Gemini 3.5 Flash-Lite lists latency-sensitive pipelines that call a model on every request among its strengths; GPT-6.1 Sol does not.
Nearly matches flagship GPT-6 Astra on agentic coding, computer use, and professional work, OpenAI says, at roughly one-fifth Astra's price
GPT-6.1 Sol
Gemini 3.5 Flash-Lite is comparatively weak here — a Lite model — the weakest of the July 2026 Gemini line on hard reasoning and coding
Factual-accuracy error rate falls to 7.7% at low reasoning effort, down from GPT-6 Sol's 11.4%
GPT-6.1 Sol
OpenAI's September 29, 2026 DevDay release — near-GPT-6-Astra coding and professional-work performance at GPT-6 Sol's existing $2/$10 price — and it is the newer of the two.
Cached input priced at $0.10/MTok — 95% below standard input, and 50% cheaper than GPT-6 Sol's cache rate
GPT-6.1 Sol
GPT-6.1 Sol lists cached input priced at $0.10/MTok — 95% below standard input, and 50% cheaper than GPT-6 Sol's cache rate among its strengths; Gemini 3.5 Flash-Lite does not.
Lowest cost at scale
Gemini 3.5 Flash-Lite
At $0.3/$2.5 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 3.5 Flash-Lite
At $0.3/$2.5 per 1M tokens it undercuts GPT-6.1 Sol, and on millions of tokens that margin decides the monthly bill.
Someone analysing very long documents or codebases
→ GPT-6.1 Sol
Larger 1.05M tokens window fits more in one prompt.
Anyone whose priority is the cheapest gemini tier at $0.30/$2.50 — built for the highest-volume, lowest-margin work
→ Gemini 3.5 Flash-Lite
It is specifically built for that.
Anyone whose priority is nearly matches flagship gpt-6 astra on agentic coding, computer use, and professional work, openai says, at roughly one-fifth astra's price
→ GPT-6.1 Sol
That is its strongest area.
Gemini 3.5 Flash-Lite: where it fits
Google's cheapest July 2026 model at $0.30/$2.50 — a high-volume, low-cost Lite tier for simple work, not frontier reasoning. Released July 21, 2026 by Google, it is built for the cheapest Gemini tier at $0.30/$2.50 — built for the highest-volume, lowest-margin work, simple classification, extraction and routing where flagship reasoning is wasted spend, latency-sensitive pipelines that call a model on every request, and pairing with a stronger model as the cheap first pass in a cascade.
Its trade-offs are real: a Lite model — the weakest of the July 2026 Gemini line on hard reasoning and coding, google did not publish its exact context window, so 1M is inferred from the family, no published SWE-Bench Verified score, and outclassed by 3.6 Flash whenever a task needs real capability rather than raw throughput. At $0.3 in / $2.5 out per million tokens, it sits in the budget price band.
GPT-6.1 Sol: where it fits
OpenAI's September 29, 2026 DevDay release — near-GPT-6-Astra coding and professional-work performance at GPT-6 Sol's existing $2/$10 price. Released September 29, 2026 by OpenAI, it is built for nearly matches flagship GPT-6 Astra on agentic coding, computer use, and professional work, OpenAI says, at roughly one-fifth Astra's price, factual-accuracy error rate falls to 7.7% at low reasoning effort, down from GPT-6 Sol's 11.4%, cached input priced at $0.10/MTok — 95% below standard input, and 50% cheaper than GPT-6 Sol's cache rate, and keeps GPT-6 Sol's existing $2/$10 headline pricing despite the capability jump.
Its trade-offs: launched in place of a hoped-for GPT-6.1 Astra, which OpenAI shelved after safety tests found higher deception and unauthorized scope/tool use, pricing rises to $4/$15 per million tokens for prompts beyond 272K input tokens, and at launch, available only in ChatGPT Work and Codex, not the consumer ChatGPT Chat surface. At $2 in / $10 out per million tokens, it sits in the mid price band.
The bottom line for this matchup
Gemini 3.5 Flash-Lite and GPT-6.1 Sol overlap enough that the right pick depends on your specific job. Gemini 3.5 Flash-Lite costs less per token; GPT-6.1 Sol holds the larger context; and each leads in its own area — Gemini 3.5 Flash-Lite for the cheapest gemini tier at $0.30/$2.50 — built for the highest-volume, lowest-margin work, GPT-6.1 Sol for nearly matches flagship gpt-6 astra on agentic coding, computer use, and professional work, openai says, at roughly one-fifth astra's price. Rather than crowning one, run the same hard task through both once and let the results decide.
Want both Gemini 3.5 Flash-Lite and GPT-6.1 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.
See pricingFrequently asked questions
Is Gemini 3.5 Flash-Lite or GPT-6.1 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 3.5 Flash-Lite leans toward the cheapest gemini tier at $0.30/$2.50 — built for the highest-volume, lowest-margin work while GPT-6.1 Sol leans toward nearly matches flagship gpt-6 astra on agentic coding, computer use, and professional work, openai says, at roughly one-fifth astra's price, and that positioning usually predicts which feels better on your codebase.
Which is cheaper, Gemini 3.5 Flash-Lite or GPT-6.1 Sol?
Gemini 3.5 Flash-Lite is cheaper — $0.3/$2.5 per 1M tokens vs $2/$10 per 1M tokens, roughly 6.7× apart on input.
Which has the bigger context window?
Effectively neither — 1M vs 1.05M tokens is a difference of a few percent. Remember advertised ≠ usable: recall typically degrades before the ceiling.
Can I use both Gemini 3.5 Flash-Lite and GPT-6.1 Sol together?
Yes — a multi-model platform like LumiChats gives you Gemini 3.5 Flash-Lite, GPT-6.1 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 3.5 Flash-Lite or GPT-6.1 Sol?
GPT-6.1 Sol — released September 29, 2026, about 2 months after Gemini 3.5 Flash-Lite.
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.