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-5.4 for strong general-purpose default or coding and software engineering. On a tight budget at scale, GPT-5.4 is the value pick.
Claude Opus 5.5 (Anthropic) and GPT-5.4 (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-5.4 is openAI's 2026 workhorse — unifies Codex and GPT into a strong default that costs half of GPT-5.5. Their biggest split is price, and the breakdown below shows exactly how that plays out for your workload.
Key differences
Price: GPT-5.4 is about 1.6× cheaper on input ($2.5/$15 per 1M tokens vs $4/$20 per 1M tokens) — modest, but it adds up at steady volume.
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 7 months (released September 22, 2026), usually meaning fresher training data and capabilities.
Specifications
Spec
Claude Opus 5.5
GPT-5.4
Provider
Anthropic (US)
OpenAI (US)
Released
September 22, 2026
March 5, 2026
Context window
1M tokens (~1,500 pages)
1M (~1,500 pages)
Price (in/out)
$4/$20 per 1M tokens
$2.5/$15 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 — 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 — Claude Opus 5.5 lists anthropic reports it surpasses Fable 5.1 on agentic coding, knowledge work, computer use, visual chart recognition, and multidisciplinary reasoning among its strengths; GPT-5.4 does not.
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; GPT-5.4 does not.
Strong general-purpose default: GPT-5.4 — Claude Opus 5.5 is comparatively weak here — 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
Coding and software engineering: GPT-5.4 — OpenAI's 2026 workhorse — unifies Codex and GPT into a strong default that costs half of GPT-5.5 — and it runs cheaper at $2.5/$15 per 1M tokens.
Document understanding and tool use: GPT-5.4 — GPT-5.4 lists document understanding and tool use among its strengths; Claude Opus 5.5 does not.
Lowest cost at scale: GPT-5.4 — At $2.5/$15 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: GPT-5.4 — At $2.5/$15 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 strong general-purpose default: GPT-5.4 — 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-5.4: where it fits
OpenAI's 2026 workhorse — unifies Codex and GPT into a strong default that costs half of GPT-5.5. Released March 5, 2026 by OpenAI, it is built for strong general-purpose default, coding and software engineering, document understanding and tool use, and 1M context with good token efficiency.
Its trade-offs: topped by GPT-5.5 on the hardest tasks, and pricier than open-weight rivals. At $2.5 in / $15 out per million tokens, it sits in the mid price band.
The bottom line for this matchup
Claude Opus 5.5 and GPT-5.4 overlap enough that the right pick depends on your specific job. GPT-5.4 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-5.4 for strong general-purpose default. 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-5.4 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-5.4 leans toward strong general-purpose default, and that positioning usually predicts which feels better on your codebase.
Which is cheaper, Claude Opus 5.5 or GPT-5.4?
GPT-5.4 is cheaper — $4/$20 per 1M tokens vs $2.5/$15 per 1M tokens, roughly 1.6× 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-5.4 together?
Yes — a multi-model platform like LumiChats gives you Claude Opus 5.5, GPT-5.4 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-5.4?
Claude Opus 5.5 — released September 22, 2026, about 7 months after GPT-5.4.
Claude Opus 5.5 vs GPT-5.4
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-5.4 for strong general-purpose default or coding and software engineering. On a tight budget at scale, GPT-5.4 is the value pick.
Claude Opus 5.5 (Anthropic) and GPT-5.4 (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-5.4 is openAI's 2026 workhorse — unifies Codex and GPT into a strong default that costs half of GPT-5.5. Their biggest split is price, and the breakdown below shows exactly how that plays out for your workload.
Key differences at a glance
▸Price: GPT-5.4 is about 1.6× cheaper on input ($2.5/$15 per 1M tokens vs $4/$20 per 1M tokens) — modest, but it adds up at steady volume.
▸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 7 months (released September 22, 2026), usually meaning fresher training data and capabilities.
Side-by-side specs
Spec
Claude Opus 5.5
GPT-5.4
Provider
Anthropic (US)
OpenAI (US)
Released
September 22, 2026
March 5, 2026
Context window
1M tokens (~1,500 pages)
1M (~1,500 pages)
Price (in/out)
$4/$20 per 1M tokens
$2.5/$15 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
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
Claude Opus 5.5 lists anthropic reports it surpasses Fable 5.1 on agentic coding, knowledge work, computer use, visual chart recognition, and multidisciplinary reasoning among its strengths; GPT-5.4 does not.
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; GPT-5.4 does not.
Strong general-purpose default
GPT-5.4
Claude Opus 5.5 is comparatively weak here — 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
Coding and software engineering
GPT-5.4
OpenAI's 2026 workhorse — unifies Codex and GPT into a strong default that costs half of GPT-5.5 — and it runs cheaper at $2.5/$15 per 1M tokens.
Document understanding and tool use
GPT-5.4
GPT-5.4 lists document understanding and tool use among its strengths; Claude Opus 5.5 does not.
Lowest cost at scale
GPT-5.4
At $2.5/$15 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
→ GPT-5.4
At $2.5/$15 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 strong general-purpose default
→ GPT-5.4
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-5.4: where it fits
OpenAI's 2026 workhorse — unifies Codex and GPT into a strong default that costs half of GPT-5.5. Released March 5, 2026 by OpenAI, it is built for strong general-purpose default, coding and software engineering, document understanding and tool use, and 1M context with good token efficiency.
Its trade-offs: topped by GPT-5.5 on the hardest tasks, and pricier than open-weight rivals. At $2.5 in / $15 out per million tokens, it sits in the mid price band.
The bottom line for this matchup
Claude Opus 5.5 and GPT-5.4 overlap enough that the right pick depends on your specific job. GPT-5.4 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-5.4 for strong general-purpose default. 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-5.4 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-5.4 leans toward strong general-purpose default, and that positioning usually predicts which feels better on your codebase.
Which is cheaper, Claude Opus 5.5 or GPT-5.4?
GPT-5.4 is cheaper — $4/$20 per 1M tokens vs $2.5/$15 per 1M tokens, roughly 1.6× 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-5.4 together?
Yes — a multi-model platform like LumiChats gives you Claude Opus 5.5, GPT-5.4 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-5.4?
Claude Opus 5.5 — released September 22, 2026, about 7 months after GPT-5.4.
Specifications and benchmarks reflect publicly reported figures as of June 2026 and may change as providers release updates. Always verify on your own workload.