Pick Claude Opus 5.5 for performs at roughly claude fable 5.1's level on most work, at 40% lower typical workload cost than opus 5 or anthropic reports it surpasses fable 5.1 on agentic coding, knowledge work, computer use, visual chart recognition, and multidisciplinary reasoning. Pick Gemini 2.5 Flash for cheapest 1m-context option or very fast. On a tight budget at scale, Gemini 2.5 Flash is the value pick.
Claude Opus 5.5 (Anthropic) and Gemini 2.5 Flash (Google) are two of the models people most often weigh against each other in 2026. Claude Opus 5.5 is anthropic's September 22, 2026 update: Fable 5.1-level performance at 40% lower cost than Opus 5, with faster output and cheaper caching. Gemini 2.5 Flash is google's ultra-cheap, fast 1M-context model for high-volume multimodal work. Their biggest split is price, and the breakdown below shows exactly how that plays out for your workload.
Key differences
Price: Gemini 2.5 Flash is about 13× cheaper on input ($0.3/$2.5 per 1M tokens vs $4/$20 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 tokens (~1,500 pages). Tie on paper — test on your own long inputs, since usable recall varies by model.
Recency: Claude Opus 5.5 is the newer model by about 16 months (released September 22, 2026), usually meaning fresher training data and capabilities.
Specifications
Spec
Claude Opus 5.5
Gemini 2.5 Flash
Provider
Anthropic (US)
Google (US)
Released
September 22, 2026
June 2025
Context window
1M tokens (~1,500 pages)
1M (~1,500 pages)
Price (in/out)
$4/$20 per 1M tokens
$0.3/$2.5 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
Performs at roughly Claude Fable 5.1's level on most work, at 40% lower typical workload cost than Opus 5: Claude Opus 5.5 — Anthropic's September 22, 2026 update: Fable 5.1-level performance at 40% lower cost than Opus 5, with faster output and cheaper caching — and it is the newer of the two.
Anthropic reports it surpasses Fable 5.1 on agentic coding, knowledge work, computer use, visual chart recognition, and multidisciplinary reasoning: Claude Opus 5.5 — Gemini 2.5 Flash is comparatively weak here — lighter reasoning than Pro tiers
Pricing cut to $4/$20 per million tokens (20% below Opus 5's $5/$25), cache reads down 60% to $0.20/MTok: Claude Opus 5.5 — Claude Opus 5.5 lists pricing cut to $4/$20 per million tokens (20% below Opus 5's $5/$25), cache reads down 60% to $0.20/MTok among its strengths; Gemini 2.5 Flash does not.
Cheapest 1M-context option: Gemini 2.5 Flash — At $0.3/$2.5 per 1M tokens it undercuts Claude Opus 5.5 ($4/$20 per 1M tokens), and that gap compounds at volume.
Very fast: Gemini 2.5 Flash — Google's ultra-cheap, fast 1M-context model for high-volume multimodal work — and it runs cheaper at $0.3/$2.5 per 1M tokens.
High-volume multimodal: Gemini 2.5 Flash — Gemini 2.5 Flash lists high-volume multimodal among its strengths; Claude Opus 5.5 does not.
Lowest cost at scale: Gemini 2.5 Flash — 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 2.5 Flash — At $0.3/$2.5 per 1M tokens it undercuts Claude Opus 5.5, and on millions of tokens that margin decides the monthly bill.
Anyone whose priority is performs at roughly claude fable 5.1's level on most work, at 40% lower typical workload cost than opus 5: Claude Opus 5.5 — It is specifically built for that.
Anyone whose priority is cheapest 1m-context option: Gemini 2.5 Flash — That is its strongest area.
Claude Opus 5.5: where it fits
Anthropic's September 22, 2026 update: Fable 5.1-level performance at 40% lower cost than Opus 5, with faster output and cheaper caching. Released September 22, 2026 by Anthropic, it is built for performs at roughly Claude Fable 5.1's level on most work, at 40% lower typical workload cost than Opus 5, anthropic reports it surpasses Fable 5.1 on agentic coding, knowledge work, computer use, visual chart recognition, and multidisciplinary reasoning, pricing cut to $4/$20 per million tokens (20% below Opus 5's $5/$25), cache reads down 60% to $0.20/MTok, and output speed increased over 30% versus Opus 5.
Its trade-offs are real: not a reasoning-ceiling upgrade over Fable 5.1 — pitched as matching its performance at lower cost, not beating it outright, like Opus 5, the headline 1M-token context is not uniformly available across every platform and plan — some API paths default to a smaller window, and first model in the 5.5 line; Anthropic has signaled Sonnet 5.5 and Haiku 5.5 are still weeks away, so the lower tiers of the family aren't out yet. At $4 in / $20 out per million tokens, it sits in the mid price band.
Gemini 2.5 Flash: where it fits
Google's ultra-cheap, fast 1M-context model for high-volume multimodal work. Released June 2025 by Google, it is built for cheapest 1M-context option, very fast, high-volume multimodal, and workspace integration.
Its trade-offs: lighter reasoning than Pro tiers, and superseded by 3.5 Flash. At $0.3 in / $2.5 out per million tokens, it sits in the budget price band.
The bottom line for this matchup
Claude Opus 5.5 and Gemini 2.5 Flash overlap enough that the right pick depends on your specific job. Gemini 2.5 Flash costs less per token; and each leads in its own area — Claude Opus 5.5 for performs at roughly claude fable 5.1's level on most work, at 40% lower typical workload cost than opus 5, Gemini 2.5 Flash for cheapest 1m-context option. Rather than crowning one, run the same hard task through both once and let the results decide.
Frequently asked questions
Is Claude Opus 5.5 or Gemini 2.5 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 Opus 5.5 leans toward performs at roughly claude fable 5.1's level on most work, at 40% lower typical workload cost than opus 5 while Gemini 2.5 Flash leans toward cheapest 1m-context option, and that positioning usually predicts which feels better on your codebase.
Which is cheaper, Claude Opus 5.5 or Gemini 2.5 Flash?
Gemini 2.5 Flash is cheaper — $4/$20 per 1M tokens vs $0.3/$2.5 per 1M tokens, roughly 13× apart on input.
Which has the bigger context window?
Both advertise 1M tokens (~1,500 pages). Remember advertised ≠ usable: recall typically degrades before the ceiling.
Can I use both Claude Opus 5.5 and Gemini 2.5 Flash together?
Yes — a multi-model platform like LumiChats gives you Claude Opus 5.5, Gemini 2.5 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 Opus 5.5 or Gemini 2.5 Flash?
Claude Opus 5.5 — released September 22, 2026, about 16 months after Gemini 2.5 Flash.
Claude Opus 5.5 vs Gemini 2.5 Flash
Anthropic · US | Google · US · Updated June 2026
Quick verdict
Pick Claude Opus 5.5 for performs at roughly claude fable 5.1's level on most work, at 40% lower typical workload cost than opus 5 or anthropic reports it surpasses fable 5.1 on agentic coding, knowledge work, computer use, visual chart recognition, and multidisciplinary reasoning. Pick Gemini 2.5 Flash for cheapest 1m-context option or very fast. On a tight budget at scale, Gemini 2.5 Flash is the value pick.
Claude Opus 5.5 (Anthropic) and Gemini 2.5 Flash (Google) are two of the models people most often weigh against each other in 2026. Claude Opus 5.5 is anthropic's September 22, 2026 update: Fable 5.1-level performance at 40% lower cost than Opus 5, with faster output and cheaper caching. Gemini 2.5 Flash is google's ultra-cheap, fast 1M-context model for high-volume multimodal work. 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 2.5 Flash is about 13× cheaper on input ($0.3/$2.5 per 1M tokens vs $4/$20 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 tokens (~1,500 pages). Tie on paper — test on your own long inputs, since usable recall varies by model.
▸Recency: Claude Opus 5.5 is the newer model by about 16 months (released September 22, 2026), usually meaning fresher training data and capabilities.
Side-by-side specs
Spec
Claude Opus 5.5
Gemini 2.5 Flash
Provider
Anthropic (US)
Google (US)
Released
September 22, 2026
June 2025
Context window
1M tokens (~1,500 pages)
1M (~1,500 pages)
Price (in/out)
$4/$20 per 1M tokens
$0.3/$2.5 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
Performs at roughly Claude Fable 5.1's level on most work, at 40% lower typical workload cost than Opus 5
Claude Opus 5.5
Anthropic's September 22, 2026 update: Fable 5.1-level performance at 40% lower cost than Opus 5, with faster output and cheaper caching — and it is the newer of the two.
Anthropic reports it surpasses Fable 5.1 on agentic coding, knowledge work, computer use, visual chart recognition, and multidisciplinary reasoning
Claude Opus 5.5
Gemini 2.5 Flash is comparatively weak here — lighter reasoning than Pro tiers
Pricing cut to $4/$20 per million tokens (20% below Opus 5's $5/$25), cache reads down 60% to $0.20/MTok
Claude Opus 5.5
Claude Opus 5.5 lists pricing cut to $4/$20 per million tokens (20% below Opus 5's $5/$25), cache reads down 60% to $0.20/MTok among its strengths; Gemini 2.5 Flash does not.
Cheapest 1M-context option
Gemini 2.5 Flash
At $0.3/$2.5 per 1M tokens it undercuts Claude Opus 5.5 ($4/$20 per 1M tokens), and that gap compounds at volume.
Very fast
Gemini 2.5 Flash
Google's ultra-cheap, fast 1M-context model for high-volume multimodal work — and it runs cheaper at $0.3/$2.5 per 1M tokens.
High-volume multimodal
Gemini 2.5 Flash
Gemini 2.5 Flash lists high-volume multimodal among its strengths; Claude Opus 5.5 does not.
Lowest cost at scale
Gemini 2.5 Flash
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 2.5 Flash
At $0.3/$2.5 per 1M tokens it undercuts Claude Opus 5.5, and on millions of tokens that margin decides the monthly bill.
Anyone whose priority is performs at roughly claude fable 5.1's level on most work, at 40% lower typical workload cost than opus 5
→ Claude Opus 5.5
It is specifically built for that.
Anyone whose priority is cheapest 1m-context option
→ Gemini 2.5 Flash
That is its strongest area.
Claude Opus 5.5: where it fits
Anthropic's September 22, 2026 update: Fable 5.1-level performance at 40% lower cost than Opus 5, with faster output and cheaper caching. Released September 22, 2026 by Anthropic, it is built for performs at roughly Claude Fable 5.1's level on most work, at 40% lower typical workload cost than Opus 5, anthropic reports it surpasses Fable 5.1 on agentic coding, knowledge work, computer use, visual chart recognition, and multidisciplinary reasoning, pricing cut to $4/$20 per million tokens (20% below Opus 5's $5/$25), cache reads down 60% to $0.20/MTok, and output speed increased over 30% versus Opus 5.
Its trade-offs are real: not a reasoning-ceiling upgrade over Fable 5.1 — pitched as matching its performance at lower cost, not beating it outright, like Opus 5, the headline 1M-token context is not uniformly available across every platform and plan — some API paths default to a smaller window, and first model in the 5.5 line; Anthropic has signaled Sonnet 5.5 and Haiku 5.5 are still weeks away, so the lower tiers of the family aren't out yet. At $4 in / $20 out per million tokens, it sits in the mid price band.
Gemini 2.5 Flash: where it fits
Google's ultra-cheap, fast 1M-context model for high-volume multimodal work. Released June 2025 by Google, it is built for cheapest 1M-context option, very fast, high-volume multimodal, and workspace integration.
Its trade-offs: lighter reasoning than Pro tiers, and superseded by 3.5 Flash. At $0.3 in / $2.5 out per million tokens, it sits in the budget price band.
The bottom line for this matchup
Claude Opus 5.5 and Gemini 2.5 Flash overlap enough that the right pick depends on your specific job. Gemini 2.5 Flash costs less per token; and each leads in its own area — Claude Opus 5.5 for performs at roughly claude fable 5.1's level on most work, at 40% lower typical workload cost than opus 5, Gemini 2.5 Flash for cheapest 1m-context option. Rather than crowning one, run the same hard task through both once and let the results decide.
Want both Claude Opus 5.5 and Gemini 2.5 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 Opus 5.5 or Gemini 2.5 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 Opus 5.5 leans toward performs at roughly claude fable 5.1's level on most work, at 40% lower typical workload cost than opus 5 while Gemini 2.5 Flash leans toward cheapest 1m-context option, and that positioning usually predicts which feels better on your codebase.
Which is cheaper, Claude Opus 5.5 or Gemini 2.5 Flash?
Gemini 2.5 Flash is cheaper — $4/$20 per 1M tokens vs $0.3/$2.5 per 1M tokens, roughly 13× apart on input.
Which has the bigger context window?
Both advertise 1M tokens (~1,500 pages). Remember advertised ≠ usable: recall typically degrades before the ceiling.
Can I use both Claude Opus 5.5 and Gemini 2.5 Flash together?
Yes — a multi-model platform like LumiChats gives you Claude Opus 5.5, Gemini 2.5 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 Opus 5.5 or Gemini 2.5 Flash?
Claude Opus 5.5 — released September 22, 2026, about 16 months after Gemini 2.5 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.