Pick Gemini 3.5 Flash for speed — roughly 4x faster than rivals or cost — about a third the price. Pick Grok 4.3 for video understanding from native video input or generating pdf, pptx, and xlsx files directly. On a tight budget at scale, Grok 4.3 is the value pick.
Gemini 3.5 Flash (Google) and Grok 4.3 (xAI) 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. Grok 4.3 is the current xAI flagship: 1M context, native video input, file generation, and live X data, ahead of the still-unreleased Grok 5. Their biggest split is price, and the breakdown below shows exactly how that plays out for your workload.
Key differences
Price: nearly identical — $1.5/$9 per 1M tokens vs $1.25/$2.5 per 1M tokens. Cost will not be the deciding factor here.
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 3.5 Flash is the newer model by about 19 days (released May 19, 2026), usually meaning fresher training data and capabilities.
Specifications
Spec
Gemini 3.5 Flash
Grok 4.3
Provider
Google (US)
xAI (US)
Released
May 19, 2026
April 30, 2026
Context window
1M (~1,500 pages)
1M (~1,500 pages)
Price (in/out)
$1.5/$9 per 1M tokens
$1.25/$2.5 per 1M tokens
Open weight?
No — API only
No — API only
Modalities
text, image, audio, video, code
text, image, video, code
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 — A core design strength of Gemini 3.5 Flash.
Cost — about a third the price: Gemini 3.5 Flash — A core design strength of Gemini 3.5 Flash.
Default in the Gemini app and Search AI Mode: Gemini 3.5 Flash — A core design strength of Gemini 3.5 Flash.
Video understanding from native video input: Grok 4.3 — A core design strength of Grok 4.3.
Generating PDF, PPTX, and XLSX files directly: Grok 4.3 — A core design strength of Grok 4.3.
Real-time questions using live X data: Grok 4.3 — A core design strength of Grok 4.3.
Lowest cost at scale: Grok 4.3 — At $1.25/$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: Grok 4.3 — At $1.25/$2.5 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 video understanding from native video input: Grok 4.3 — 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.
Grok 4.3: where it fits
The current xAI flagship: 1M context, native video input, file generation, and live X data, ahead of the still-unreleased Grok 5. Released April 30, 2026 by xAI, it is built for video understanding from native video input, generating PDF, PPTX, and XLSX files directly, real-time questions using live X data, and long-context, multi-agent reasoning.
Its trade-offs: higher context pricing on requests above 200K tokens, and less independent benchmark coverage than OpenAI, Anthropic, or Google. At $1.25 in / $2.5 out per million tokens, it sits in the mid price band.
The bottom line for this matchup
Gemini 3.5 Flash and Grok 4.3 overlap enough that the right pick depends on your specific job. Grok 4.3 costs less per token; and each leads in its own area — Gemini 3.5 Flash for speed — roughly 4x faster than rivals, Grok 4.3 for video understanding from native video input. 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 Grok 4.3 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 Grok 4.3 leans toward video understanding from native video input, and that positioning usually predicts which feels better on your codebase.
Which is cheaper, Gemini 3.5 Flash or Grok 4.3?
Grok 4.3 is cheaper — $1.5/$9 per 1M tokens vs $1.25/$2.5 per 1M tokens, roughly 1.2× 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 Grok 4.3 together?
Yes — a multi-model platform like LumiChats gives you Gemini 3.5 Flash, Grok 4.3 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 Grok 4.3?
Gemini 3.5 Flash — released May 19, 2026, about 19 days after Grok 4.3.
Gemini 3.5 Flash vs Grok 4.3
Google · US | xAI · 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 Grok 4.3 for video understanding from native video input or generating pdf, pptx, and xlsx files directly. On a tight budget at scale, Grok 4.3 is the value pick.
Gemini 3.5 Flash (Google) and Grok 4.3 (xAI) 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. Grok 4.3 is the current xAI flagship: 1M context, native video input, file generation, and live X data, ahead of the still-unreleased Grok 5. Their biggest split is price, and the breakdown below shows exactly how that plays out for your workload.
Key differences at a glance
▸Price: nearly identical — $1.5/$9 per 1M tokens vs $1.25/$2.5 per 1M tokens. Cost will not be the deciding factor here.
▸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 3.5 Flash is the newer model by about 19 days (released May 19, 2026), usually meaning fresher training data and capabilities.
Side-by-side specs
Spec
Gemini 3.5 Flash
Grok 4.3
Provider
Google (US)
xAI (US)
Released
May 19, 2026
April 30, 2026
Context window
1M (~1,500 pages)
1M (~1,500 pages)
Price (in/out)
$1.5/$9 per 1M tokens
$1.25/$2.5 per 1M tokens
Open weight?
No — API only
No — API only
Modalities
text, image, audio, video, code
text, image, video, code
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
A core design strength of Gemini 3.5 Flash.
Cost — about a third the price
Gemini 3.5 Flash
A core design strength of Gemini 3.5 Flash.
Default in the Gemini app and Search AI Mode
Gemini 3.5 Flash
A core design strength of Gemini 3.5 Flash.
Video understanding from native video input
Grok 4.3
A core design strength of Grok 4.3.
Generating PDF, PPTX, and XLSX files directly
Grok 4.3
A core design strength of Grok 4.3.
Real-time questions using live X data
Grok 4.3
A core design strength of Grok 4.3.
Lowest cost at scale
Grok 4.3
At $1.25/$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
→ Grok 4.3
At $1.25/$2.5 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 video understanding from native video input
→ Grok 4.3
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.
Grok 4.3: where it fits
The current xAI flagship: 1M context, native video input, file generation, and live X data, ahead of the still-unreleased Grok 5. Released April 30, 2026 by xAI, it is built for video understanding from native video input, generating PDF, PPTX, and XLSX files directly, real-time questions using live X data, and long-context, multi-agent reasoning.
Its trade-offs: higher context pricing on requests above 200K tokens, and less independent benchmark coverage than OpenAI, Anthropic, or Google. At $1.25 in / $2.5 out per million tokens, it sits in the mid price band.
The bottom line for this matchup
Gemini 3.5 Flash and Grok 4.3 overlap enough that the right pick depends on your specific job. Grok 4.3 costs less per token; and each leads in its own area — Gemini 3.5 Flash for speed — roughly 4x faster than rivals, Grok 4.3 for video understanding from native video input. Rather than crowning one, run the same hard task through both once and let the results decide.
Want both Gemini 3.5 Flash and Grok 4.3 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 Grok 4.3 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 Grok 4.3 leans toward video understanding from native video input, and that positioning usually predicts which feels better on your codebase.
Which is cheaper, Gemini 3.5 Flash or Grok 4.3?
Grok 4.3 is cheaper — $1.5/$9 per 1M tokens vs $1.25/$2.5 per 1M tokens, roughly 1.2× 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 Grok 4.3 together?
Yes — a multi-model platform like LumiChats gives you Gemini 3.5 Flash, Grok 4.3 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 Grok 4.3?
Gemini 3.5 Flash — released May 19, 2026, about 19 days after Grok 4.3.
Specifications and benchmarks reflect publicly reported figures as of June 2026 and may change as providers release updates. Always verify on your own workload.