Pick Claude Fable 5 for the hardest reasoning and most complex problems or long-horizon, multi-step agentic work. Pick Gemini 3.5 Flash for speed — roughly 4x faster than rivals or cost — about a third the price. On a tight budget at scale, Gemini 3.5 Flash is the value pick.
Claude Fable 5 (Anthropic) and Gemini 3.5 Flash (Google) are two of the models people most often weigh against each other in 2026. Claude Fable 5 is anthropic's top public Mythos-class model and its most capable yet, though tier access was temporarily suspended in June 2026 under a US export-control directive. Gemini 3.5 Flash is google's fast, cheap class that now beats last year's premium Pro — the value-and-reach play. Their biggest split is price, and the breakdown below shows exactly how that plays out for your workload.
Key differences
Price: Gemini 3.5 Flash is about 6.7× cheaper on input ($1.5/$9 per 1M tokens vs $10/$50 per 1M tokens) — a large enough gap that at scale it can be the single biggest line item in the decision.
Context window: both advertise 1M (~1,500 pages). Tie on paper — test on your own long inputs, since usable recall varies by model.
Recency: Claude Fable 5 is the newer model by about 21 days (released June 9, 2026), usually meaning fresher training data and capabilities.
Specifications
Spec
Claude Fable 5
Gemini 3.5 Flash
Provider
Anthropic (US)
Google (US)
Released
June 9, 2026
May 19, 2026
Context window
1M (~1,500 pages)
1M (~1,500 pages)
Price (in/out)
$10/$50 per 1M tokens
$1.5/$9 per 1M tokens
Open weight?
No — API only
No — API only
Modalities
text, image, code
text, image, audio, video, code
SWE-Bench Verified
Not published
Not published
MRCR v2 @ 1M
Not published
Not published
Who wins what
The hardest reasoning and most complex problems: Claude Fable 5 — A core design strength of Claude Fable 5.
Long-horizon, multi-step agentic work: Claude Fable 5 — A core design strength of Claude Fable 5.
Frontier-level analysis and research: Claude Fable 5 — A core design strength of Claude Fable 5.
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.
Lowest cost at scale: Gemini 3.5 Flash — At $1.5/$9 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 — At $1.5/$9 per 1M tokens it undercuts Claude Fable 5, and on millions of tokens that margin decides the monthly bill.
Anyone whose priority is the hardest reasoning and most complex problems: Claude Fable 5 — It is specifically built for that.
Anyone whose priority is speed — roughly 4x faster than rivals: Gemini 3.5 Flash — That is its strongest area.
Claude Fable 5: where it fits
Anthropic's top public Mythos-class model and its most capable yet, though tier access was temporarily suspended in June 2026 under a US export-control directive. Released June 9, 2026 by Anthropic, it is built for the hardest reasoning and most complex problems, long-horizon, multi-step agentic work, frontier-level analysis and research, and work where maximum capability outweighs cost.
Its trade-offs are real: highest price in the Claude lineup, and tier access was temporarily suspended in June 2026 under a US export-control directive. At $10 in / $50 out per million tokens, it sits in the premium price band.
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: 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.
The bottom line for this matchup
Claude Fable 5 and Gemini 3.5 Flash overlap enough that the right pick depends on your specific job. Gemini 3.5 Flash costs less per token; and each leads in its own area — Claude Fable 5 for the hardest reasoning and most complex problems, Gemini 3.5 Flash for speed — roughly 4x faster than rivals. Rather than crowning one, run the same hard task through both once and let the results decide.
Frequently asked questions
Is Claude Fable 5 or Gemini 3.5 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, Claude Fable 5 leans toward the hardest reasoning and most complex problems while Gemini 3.5 Flash leans toward speed — roughly 4x faster than rivals, and that positioning usually predicts which feels better on your codebase.
Which is cheaper, Claude Fable 5 or Gemini 3.5 Flash?
Gemini 3.5 Flash is cheaper — $10/$50 per 1M tokens vs $1.5/$9 per 1M tokens, roughly 6.7× 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 Claude Fable 5 and Gemini 3.5 Flash together?
Yes — a multi-model platform like LumiChats gives you Claude Fable 5, Gemini 3.5 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, Claude Fable 5 or Gemini 3.5 Flash?
Claude Fable 5 — released June 9, 2026, about 21 days after Gemini 3.5 Flash.
Claude Fable 5 vs Gemini 3.5 Flash
Anthropic · US | Google · US · Updated June 2026
Quick verdict
Pick Claude Fable 5 for the hardest reasoning and most complex problems or long-horizon, multi-step agentic work. Pick Gemini 3.5 Flash for speed — roughly 4x faster than rivals or cost — about a third the price. On a tight budget at scale, Gemini 3.5 Flash is the value pick.
Claude Fable 5 (Anthropic) and Gemini 3.5 Flash (Google) are two of the models people most often weigh against each other in 2026. Claude Fable 5 is anthropic's top public Mythos-class model and its most capable yet, though tier access was temporarily suspended in June 2026 under a US export-control directive. Gemini 3.5 Flash is google's fast, cheap class that now beats last year's premium Pro — the value-and-reach play. 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 3.5 Flash is about 6.7× cheaper on input ($1.5/$9 per 1M tokens vs $10/$50 per 1M tokens) — a large enough gap that at scale it can be the single biggest line item in the decision.
▸Context window: both advertise 1M (~1,500 pages). Tie on paper — test on your own long inputs, since usable recall varies by model.
▸Recency: Claude Fable 5 is the newer model by about 21 days (released June 9, 2026), usually meaning fresher training data and capabilities.
Side-by-side specs
Spec
Claude Fable 5
Gemini 3.5 Flash
Provider
Anthropic (US)
Google (US)
Released
June 9, 2026
May 19, 2026
Context window
1M (~1,500 pages)
1M (~1,500 pages)
Price (in/out)
$10/$50 per 1M tokens
$1.5/$9 per 1M tokens
Open weight?
No — API only
No — API only
Modalities
text, image, code
text, image, audio, video, code
SWE-Bench Verified
Not published
Not published
MRCR v2 @ 1M
Not published
Not published
Who wins what
The hardest reasoning and most complex problems
Claude Fable 5
A core design strength of Claude Fable 5.
Long-horizon, multi-step agentic work
Claude Fable 5
A core design strength of Claude Fable 5.
Frontier-level analysis and research
Claude Fable 5
A core design strength of Claude Fable 5.
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.
Lowest cost at scale
Gemini 3.5 Flash
At $1.5/$9 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
At $1.5/$9 per 1M tokens it undercuts Claude Fable 5, and on millions of tokens that margin decides the monthly bill.
Anyone whose priority is the hardest reasoning and most complex problems
→ Claude Fable 5
It is specifically built for that.
Anyone whose priority is speed — roughly 4x faster than rivals
→ Gemini 3.5 Flash
That is its strongest area.
Claude Fable 5: where it fits
Anthropic's top public Mythos-class model and its most capable yet, though tier access was temporarily suspended in June 2026 under a US export-control directive. Released June 9, 2026 by Anthropic, it is built for the hardest reasoning and most complex problems, long-horizon, multi-step agentic work, frontier-level analysis and research, and work where maximum capability outweighs cost.
Its trade-offs are real: highest price in the Claude lineup, and tier access was temporarily suspended in June 2026 under a US export-control directive. At $10 in / $50 out per million tokens, it sits in the premium price band.
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: 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.
The bottom line for this matchup
Claude Fable 5 and Gemini 3.5 Flash overlap enough that the right pick depends on your specific job. Gemini 3.5 Flash costs less per token; and each leads in its own area — Claude Fable 5 for the hardest reasoning and most complex problems, Gemini 3.5 Flash for speed — roughly 4x faster than rivals. Rather than crowning one, run the same hard task through both once and let the results decide.
Want both Claude Fable 5 and Gemini 3.5 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 Claude Fable 5 or Gemini 3.5 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, Claude Fable 5 leans toward the hardest reasoning and most complex problems while Gemini 3.5 Flash leans toward speed — roughly 4x faster than rivals, and that positioning usually predicts which feels better on your codebase.
Which is cheaper, Claude Fable 5 or Gemini 3.5 Flash?
Gemini 3.5 Flash is cheaper — $10/$50 per 1M tokens vs $1.5/$9 per 1M tokens, roughly 6.7× 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 Claude Fable 5 and Gemini 3.5 Flash together?
Yes — a multi-model platform like LumiChats gives you Claude Fable 5, Gemini 3.5 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, Claude Fable 5 or Gemini 3.5 Flash?
Claude Fable 5 — released June 9, 2026, about 21 days 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.