Pick Gemini 3.5 Flash for speed — roughly 4x faster than rivals or cost — about a third the price. Pick Gemini 3.8 Flash for long-horizon agentic coding (deepswe v1.1) or cost-efficient workhorse performance beating larger models at same price as 3.7 flash. On a tight budget at scale, Gemini 3.8 Flash is the value pick.
Gemini 3.5 Flash (Google) and Gemini 3.8 Flash (Google DeepMind) are two of the models people most often weigh against each other in 2026. Gemini 3.5 Flash is google's fast, cheap class that now beats last year's premium Pro — the value-and-reach play. Gemini 3.8 Flash is google's cost-efficient workhorse model released September 2, 2026, tuned for long-horizon coding and autonomous agents, launched alongside a restricted 'Cyber' variant for vulnerability research. Their biggest split is price, and the breakdown below shows exactly how that plays out for your workload.
Key differences
Price: Gemini 3.8 Flash is about 2× cheaper on input ($0.75/$3.75 per 1M tokens vs $1.5/$9 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: Gemini 3.8 Flash is the newer model by about 4 months (released September 2, 2026), usually meaning fresher training data and capabilities.
Specifications
Spec
Gemini 3.5 Flash
Gemini 3.8 Flash
Provider
Google (US)
Google DeepMind (US)
Released
May 19, 2026
September 2, 2026
Context window
1M (~1,500 pages)
1M tokens (~1,500 pages)
Price (in/out)
$1.5/$9 per 1M tokens
$0.75/$3.75 per 1M tokens
Open weight?
No — API only
No — API only
Modalities
text, image, audio, video, code
text, image, audio, video
SWE-Bench Verified
Not published
Not published
MRCR v2 @ 1M
Not published
Not published
Who wins what
Speed — roughly 4x faster than rivals: Gemini 3.5 Flash — Gemini 3.5 Flash lists speed — roughly 4x faster than rivals among its strengths; Gemini 3.8 Flash does not.
Cost — about a third the price: Gemini 3.5 Flash — Gemini 3.8 Flash is comparatively weak here — introductory price doubles on January 1, 2027
Default in the Gemini app and Search AI Mode: Gemini 3.5 Flash — Gemini 3.8 Flash is comparatively weak here — built on the same base model as Gemini 3.7 Flash (a post-training update, not a freshly pretrained model)
Long-horizon agentic coding (DeepSWE v1.1): Gemini 3.8 Flash — Google's cost-efficient workhorse model released September 2, 2026, tuned for long-horizon coding and autonomous agents, launched alongside a restricted 'Cyber' variant for vulnerability research — and it runs cheaper at $0.75/$3.75 per 1M tokens.
Cost-efficient workhorse performance beating larger models at same price as 3.7 Flash: Gemini 3.8 Flash — At $0.75/$3.75 per 1M tokens it undercuts Gemini 3.5 Flash ($1.5/$9 per 1M tokens), and that gap compounds at volume.
Vals Finance Agent V2 benchmark (61.4%, ahead of Claude Opus 5's 58.6%); also leads a weak field on the Harvey legal benchmark (10.0%): Gemini 3.8 Flash — Google's cost-efficient workhorse model released September 2, 2026, tuned for long-horizon coding and autonomous agents, launched alongside a restricted 'Cyber' variant for vulnerability research — and it is the newer of the two.
Lowest cost at scale: Gemini 3.8 Flash — At $0.75/$3.75 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 3.8 Flash — At $0.75/$3.75 per 1M tokens it undercuts Gemini 3.5 Flash, and on millions of tokens that margin decides the monthly bill.
Anyone whose priority is speed — roughly 4x faster than rivals: Gemini 3.5 Flash — It is specifically built for that.
Anyone whose priority is long-horizon agentic coding (deepswe v1.1): Gemini 3.8 Flash — That is its strongest area.
Gemini 3.5 Flash: where it fits
Google's fast, cheap class that now beats last year's premium Pro — the value-and-reach play. Released May 19, 2026 by Google, it is built for speed — roughly 4x faster than rivals, cost — about a third the price, default in the Gemini app and Search AI Mode, and high-volume multimodal work.
Its trade-offs are real: flash tier, not the deepest reasoning, and pro-tier 3.5 held back at launch. At $1.5 in / $9 out per million tokens, it sits in the mid price band.
Gemini 3.8 Flash: where it fits
Google's cost-efficient workhorse model released September 2, 2026, tuned for long-horizon coding and autonomous agents, launched alongside a restricted 'Cyber' variant for vulnerability research. Released September 2, 2026 by Google DeepMind, it is built for long-horizon agentic coding (DeepSWE v1.1), cost-efficient workhorse performance beating larger models at same price as 3.7 Flash, vals Finance Agent V2 benchmark (61.4%, ahead of Claude Opus 5's 58.6%); also leads a weak field on the Harvey legal benchmark (10.0%), and prompt-injection robustness (Gray Swan benchmark).
Its trade-offs: still a mid-tier 'Flash' model, not Google's frontier flagship (which remains unreleased), introductory price doubles on January 1, 2027, hLE-Verified score (54.9%) trails top frontier reasoning models, and built on the same base model as Gemini 3.7 Flash (a post-training update, not a freshly pretrained model). At $0.75 in / $3.75 out per million tokens, it sits in the budget price band.
The bottom line for this matchup
Gemini 3.5 Flash and Gemini 3.8 Flash overlap enough that the right pick depends on your specific job. Gemini 3.8 Flash costs less per token; and each leads in its own area — Gemini 3.5 Flash for speed — roughly 4x faster than rivals, Gemini 3.8 Flash for long-horizon agentic coding (deepswe v1.1). Rather than crowning one, run the same hard task through both once and let the results decide.
Frequently asked questions
Is Gemini 3.5 Flash or Gemini 3.8 Flash 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 leans toward speed — roughly 4x faster than rivals while Gemini 3.8 Flash leans toward long-horizon agentic coding (deepswe v1.1), and that positioning usually predicts which feels better on your codebase.
Which is cheaper, Gemini 3.5 Flash or Gemini 3.8 Flash?
Gemini 3.8 Flash is cheaper — $1.5/$9 per 1M tokens vs $0.75/$3.75 per 1M tokens, roughly 2× 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 3.5 Flash and Gemini 3.8 Flash together?
Yes — a multi-model platform like LumiChats gives you Gemini 3.5 Flash, Gemini 3.8 Flash 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 or Gemini 3.8 Flash?
Gemini 3.8 Flash — released September 2, 2026, about 4 months after Gemini 3.5 Flash.
Gemini 3.5 Flash vs Gemini 3.8 Flash
Google · US | Google DeepMind · US · Updated June 2026
Quick verdict
Pick Gemini 3.5 Flash for speed — roughly 4x faster than rivals or cost — about a third the price. Pick Gemini 3.8 Flash for long-horizon agentic coding (deepswe v1.1) or cost-efficient workhorse performance beating larger models at same price as 3.7 flash. On a tight budget at scale, Gemini 3.8 Flash is the value pick.
Gemini 3.5 Flash (Google) and Gemini 3.8 Flash (Google DeepMind) are two of the models people most often weigh against each other in 2026. Gemini 3.5 Flash is google's fast, cheap class that now beats last year's premium Pro — the value-and-reach play. Gemini 3.8 Flash is google's cost-efficient workhorse model released September 2, 2026, tuned for long-horizon coding and autonomous agents, launched alongside a restricted 'Cyber' variant for vulnerability research. 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 3.8 Flash is about 2× cheaper on input ($0.75/$3.75 per 1M tokens vs $1.5/$9 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: Gemini 3.8 Flash is the newer model by about 4 months (released September 2, 2026), usually meaning fresher training data and capabilities.
Side-by-side specs
Spec
Gemini 3.5 Flash
Gemini 3.8 Flash
Provider
Google (US)
Google DeepMind (US)
Released
May 19, 2026
September 2, 2026
Context window
1M (~1,500 pages)
1M tokens (~1,500 pages)
Price (in/out)
$1.5/$9 per 1M tokens
$0.75/$3.75 per 1M tokens
Open weight?
No — API only
No — API only
Modalities
text, image, audio, video, code
text, image, audio, video
SWE-Bench Verified
Not published
Not published
MRCR v2 @ 1M
Not published
Not published
Who wins what
Speed — roughly 4x faster than rivals
Gemini 3.5 Flash
Gemini 3.5 Flash lists speed — roughly 4x faster than rivals among its strengths; Gemini 3.8 Flash does not.
Cost — about a third the price
Gemini 3.5 Flash
Gemini 3.8 Flash is comparatively weak here — introductory price doubles on January 1, 2027
Default in the Gemini app and Search AI Mode
Gemini 3.5 Flash
Gemini 3.8 Flash is comparatively weak here — built on the same base model as Gemini 3.7 Flash (a post-training update, not a freshly pretrained model)
Long-horizon agentic coding (DeepSWE v1.1)
Gemini 3.8 Flash
Google's cost-efficient workhorse model released September 2, 2026, tuned for long-horizon coding and autonomous agents, launched alongside a restricted 'Cyber' variant for vulnerability research — and it runs cheaper at $0.75/$3.75 per 1M tokens.
Cost-efficient workhorse performance beating larger models at same price as 3.7 Flash
Gemini 3.8 Flash
At $0.75/$3.75 per 1M tokens it undercuts Gemini 3.5 Flash ($1.5/$9 per 1M tokens), and that gap compounds at volume.
Vals Finance Agent V2 benchmark (61.4%, ahead of Claude Opus 5's 58.6%); also leads a weak field on the Harvey legal benchmark (10.0%)
Gemini 3.8 Flash
Google's cost-efficient workhorse model released September 2, 2026, tuned for long-horizon coding and autonomous agents, launched alongside a restricted 'Cyber' variant for vulnerability research — and it is the newer of the two.
Lowest cost at scale
Gemini 3.8 Flash
At $0.75/$3.75 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 3.8 Flash
At $0.75/$3.75 per 1M tokens it undercuts Gemini 3.5 Flash, and on millions of tokens that margin decides the monthly bill.
Anyone whose priority is speed — roughly 4x faster than rivals
→ Gemini 3.5 Flash
It is specifically built for that.
Anyone whose priority is long-horizon agentic coding (deepswe v1.1)
→ Gemini 3.8 Flash
That is its strongest area.
Gemini 3.5 Flash: where it fits
Google's fast, cheap class that now beats last year's premium Pro — the value-and-reach play. Released May 19, 2026 by Google, it is built for speed — roughly 4x faster than rivals, cost — about a third the price, default in the Gemini app and Search AI Mode, and high-volume multimodal work.
Its trade-offs are real: flash tier, not the deepest reasoning, and pro-tier 3.5 held back at launch. At $1.5 in / $9 out per million tokens, it sits in the mid price band.
Gemini 3.8 Flash: where it fits
Google's cost-efficient workhorse model released September 2, 2026, tuned for long-horizon coding and autonomous agents, launched alongside a restricted 'Cyber' variant for vulnerability research. Released September 2, 2026 by Google DeepMind, it is built for long-horizon agentic coding (DeepSWE v1.1), cost-efficient workhorse performance beating larger models at same price as 3.7 Flash, vals Finance Agent V2 benchmark (61.4%, ahead of Claude Opus 5's 58.6%); also leads a weak field on the Harvey legal benchmark (10.0%), and prompt-injection robustness (Gray Swan benchmark).
Its trade-offs: still a mid-tier 'Flash' model, not Google's frontier flagship (which remains unreleased), introductory price doubles on January 1, 2027, hLE-Verified score (54.9%) trails top frontier reasoning models, and built on the same base model as Gemini 3.7 Flash (a post-training update, not a freshly pretrained model). At $0.75 in / $3.75 out per million tokens, it sits in the budget price band.
The bottom line for this matchup
Gemini 3.5 Flash and Gemini 3.8 Flash overlap enough that the right pick depends on your specific job. Gemini 3.8 Flash costs less per token; and each leads in its own area — Gemini 3.5 Flash for speed — roughly 4x faster than rivals, Gemini 3.8 Flash for long-horizon agentic coding (deepswe v1.1). Rather than crowning one, run the same hard task through both once and let the results decide.
Want both Gemini 3.5 Flash and Gemini 3.8 Flash 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 3.5 Flash or Gemini 3.8 Flash 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 leans toward speed — roughly 4x faster than rivals while Gemini 3.8 Flash leans toward long-horizon agentic coding (deepswe v1.1), and that positioning usually predicts which feels better on your codebase.
Which is cheaper, Gemini 3.5 Flash or Gemini 3.8 Flash?
Gemini 3.8 Flash is cheaper — $1.5/$9 per 1M tokens vs $0.75/$3.75 per 1M tokens, roughly 2× 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 3.5 Flash and Gemini 3.8 Flash together?
Yes — a multi-model platform like LumiChats gives you Gemini 3.5 Flash, Gemini 3.8 Flash 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 or Gemini 3.8 Flash?
Gemini 3.8 Flash — released September 2, 2026, about 4 months after Gemini 3.5 Flash.
Specifications and benchmarks reflect publicly reported figures as of June 2026 and may change as providers release updates. Always verify on your own workload.