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 GPT-5.5 for terminal, cli and computer-use automation or long-horizon tool sequencing. On a tight budget at scale, Claude Opus 5.5 is the value pick.
Claude Opus 5.5 (Anthropic) and GPT-5.5 (OpenAI) 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. GPT-5.5 is openAI's first fully retrained base since GPT-4.5 — the terminal and computer-use champion. Their biggest split is price, and the breakdown below shows exactly how that plays out for your workload.
Key differences
Price: nearly identical — $4/$20 per 1M tokens vs $5/$30 per 1M tokens. Cost will not be the deciding factor here.
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 5 months (released September 22, 2026), usually meaning fresher training data and capabilities.
Specifications
Spec
Claude Opus 5.5
GPT-5.5
Provider
Anthropic (US)
OpenAI (US)
Released
September 22, 2026
April 23, 2026
Context window
1M tokens (~1,500 pages)
1M (~1,500 pages)
Price (in/out)
$4/$20 per 1M tokens
$5/$30 per 1M tokens
Open weight?
No — API only
No — API only
Modalities
text, image, code
text, image, 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 — At $4/$20 per 1M tokens it undercuts GPT-5.5 ($5/$30 per 1M tokens), and that gap compounds at volume.
Anthropic reports it surpasses Fable 5.1 on agentic coding, knowledge work, computer use, visual chart recognition, and multidisciplinary reasoning: Claude Opus 5.5 — GPT-5.5 is comparatively weak here — trails Opus 4.8 on hardest coding benchmarks
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 — GPT-5.5 is comparatively weak here — tiered long-context pricing above 272K tokens
Terminal, CLI and computer-use automation: GPT-5.5 — GPT-5.5 lists terminal, CLI and computer-use automation among its strengths; Claude Opus 5.5 does not.
Long-horizon tool sequencing: GPT-5.5 — GPT-5.5 lists long-horizon tool sequencing among its strengths; Claude Opus 5.5 does not.
Strong agentic coding and reasoning: GPT-5.5 — Claude Opus 5.5 is comparatively weak here — not a reasoning-ceiling upgrade over Fable 5.1 — pitched as matching its performance at lower cost, not beating it outright
Lowest cost at scale: Claude Opus 5.5 — At $4/$20 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: Claude Opus 5.5 — At $4/$20 per 1M tokens it undercuts GPT-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 terminal, cli and computer-use automation: GPT-5.5 — 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.
GPT-5.5: where it fits
OpenAI's first fully retrained base since GPT-4.5 — the terminal and computer-use champion. Released April 23, 2026 by OpenAI, it is built for terminal, CLI and computer-use automation, long-horizon tool sequencing, strong agentic coding and reasoning, and browser-driving agents.
Its trade-offs: trails Opus 4.8 on hardest coding benchmarks, and tiered long-context pricing above 272K tokens. At $5 in / $30 out per million tokens, it sits in the premium price band.
The bottom line for this matchup
Claude Opus 5.5 and GPT-5.5 overlap enough that the right pick depends on your specific job. Claude Opus 5.5 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, GPT-5.5 for terminal, cli and computer-use automation. 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 GPT-5.5 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 GPT-5.5 leans toward terminal, cli and computer-use automation, and that positioning usually predicts which feels better on your codebase.
Which is cheaper, Claude Opus 5.5 or GPT-5.5?
Claude Opus 5.5 is cheaper — $4/$20 per 1M tokens vs $5/$30 per 1M tokens, roughly 1.3× 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 GPT-5.5 together?
Yes — a multi-model platform like LumiChats gives you Claude Opus 5.5, GPT-5.5 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 GPT-5.5?
Claude Opus 5.5 — released September 22, 2026, about 5 months after GPT-5.5.
Claude Opus 5.5 vs GPT-5.5
Anthropic · US | OpenAI · 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 GPT-5.5 for terminal, cli and computer-use automation or long-horizon tool sequencing. On a tight budget at scale, Claude Opus 5.5 is the value pick.
Claude Opus 5.5 (Anthropic) and GPT-5.5 (OpenAI) 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. GPT-5.5 is openAI's first fully retrained base since GPT-4.5 — the terminal and computer-use champion. 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 — $4/$20 per 1M tokens vs $5/$30 per 1M tokens. Cost will not be the deciding factor here.
▸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 5 months (released September 22, 2026), usually meaning fresher training data and capabilities.
Side-by-side specs
Spec
Claude Opus 5.5
GPT-5.5
Provider
Anthropic (US)
OpenAI (US)
Released
September 22, 2026
April 23, 2026
Context window
1M tokens (~1,500 pages)
1M (~1,500 pages)
Price (in/out)
$4/$20 per 1M tokens
$5/$30 per 1M tokens
Open weight?
No — API only
No — API only
Modalities
text, image, code
text, image, 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
At $4/$20 per 1M tokens it undercuts GPT-5.5 ($5/$30 per 1M tokens), and that gap compounds at volume.
Anthropic reports it surpasses Fable 5.1 on agentic coding, knowledge work, computer use, visual chart recognition, and multidisciplinary reasoning
Claude Opus 5.5
GPT-5.5 is comparatively weak here — trails Opus 4.8 on hardest coding benchmarks
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
GPT-5.5 is comparatively weak here — tiered long-context pricing above 272K tokens
Terminal, CLI and computer-use automation
GPT-5.5
GPT-5.5 lists terminal, CLI and computer-use automation among its strengths; Claude Opus 5.5 does not.
Long-horizon tool sequencing
GPT-5.5
GPT-5.5 lists long-horizon tool sequencing among its strengths; Claude Opus 5.5 does not.
Strong agentic coding and reasoning
GPT-5.5
Claude Opus 5.5 is comparatively weak here — not a reasoning-ceiling upgrade over Fable 5.1 — pitched as matching its performance at lower cost, not beating it outright
Lowest cost at scale
Claude Opus 5.5
At $4/$20 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
→ Claude Opus 5.5
At $4/$20 per 1M tokens it undercuts GPT-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 terminal, cli and computer-use automation
→ GPT-5.5
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.
GPT-5.5: where it fits
OpenAI's first fully retrained base since GPT-4.5 — the terminal and computer-use champion. Released April 23, 2026 by OpenAI, it is built for terminal, CLI and computer-use automation, long-horizon tool sequencing, strong agentic coding and reasoning, and browser-driving agents.
Its trade-offs: trails Opus 4.8 on hardest coding benchmarks, and tiered long-context pricing above 272K tokens. At $5 in / $30 out per million tokens, it sits in the premium price band.
The bottom line for this matchup
Claude Opus 5.5 and GPT-5.5 overlap enough that the right pick depends on your specific job. Claude Opus 5.5 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, GPT-5.5 for terminal, cli and computer-use automation. Rather than crowning one, run the same hard task through both once and let the results decide.
Want both Claude Opus 5.5 and GPT-5.5 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.
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 GPT-5.5 leans toward terminal, cli and computer-use automation, and that positioning usually predicts which feels better on your codebase.
Which is cheaper, Claude Opus 5.5 or GPT-5.5?
Claude Opus 5.5 is cheaper — $4/$20 per 1M tokens vs $5/$30 per 1M tokens, roughly 1.3× 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 GPT-5.5 together?
Yes — a multi-model platform like LumiChats gives you Claude Opus 5.5, GPT-5.5 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 GPT-5.5?
Claude Opus 5.5 — released September 22, 2026, about 5 months after GPT-5.5.
Specifications and benchmarks reflect publicly reported figures as of June 2026 and may change as providers release updates. Always verify on your own workload.