Both are Anthropic models. Claude Opus 5.5 is the newer, generally stronger default; reach for Claude Opus 5 when a specific cost or latency profile matters more than the latest capabilities.
Claude Opus 5 and Claude Opus 5.5 are both Anthropic models, so the real question is not which lab to trust but which tier fits your workload and budget. Claude Opus 5 is anthropic's July 2026 flagship at $5/$25 with a 1M window and an effort dial — near-frontier quality pitched on cost per task, not raw peak. 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. Since both come from the same lab, the comparison below focuses on the tier-and-cost trade-offs that actually separate them.
Key differences
Price: nearly identical — $5/$25 per 1M tokens vs $4/$20 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: Claude Opus 5.5 is the newer model by about 2 months (released September 22, 2026), usually meaning fresher training data and capabilities.
Specifications
Spec
Claude Opus 5
Claude Opus 5.5
Provider
Anthropic (US)
Anthropic (US)
Released
July 24, 2026
September 22, 2026
Context window
1M (~1,500 pages)
1M tokens (~1,500 pages)
Price (in/out)
$5/$25 per 1M tokens
$4/$20 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
Frontier reasoning at lower cost per task — Anthropic reports it more than doubling Opus 4.8 on Frontier-Bench v0.1: Claude Opus 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
Agentic coding — within 0.5% of Fable 5's peak CursorBench 3.2 score at half the cost per task (Anthropic's figures): Claude Opus 5 — Claude Opus 5 lists agentic coding — within 0.5% of Fable 5's peak CursorBench 3.2 score at half the cost per task (Anthropic's figures) among its strengths; Claude Opus 5.5 does not.
Computer use — surpasses Fable 5's best OSWorld 2.0 result at just over a third of the cost: Claude Opus 5 — Claude Opus 5 lists computer use — surpasses Fable 5's best OSWorld 2.0 result at just over a third of the cost among its strengths; Claude Opus 5.5 does not.
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 Claude Opus 5 ($5/$25 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 — Claude Opus 5 is comparatively weak here — behind Mythos 5 on cybersecurity exploitation and biology research, by Anthropic's own account
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 — 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 runs cheaper at $4/$20 per 1M tokens.
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 Claude Opus 5, and on millions of tokens that margin decides the monthly bill.
Anyone whose priority is frontier reasoning at lower cost per task — anthropic reports it more than doubling opus 4.8 on frontier-bench v0.1: Claude Opus 5 — It is specifically built for that.
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 — That is its strongest area.
Claude Opus 5: where it fits
Anthropic's July 2026 flagship at $5/$25 with a 1M window and an effort dial — near-frontier quality pitched on cost per task, not raw peak. Released July 24, 2026 by Anthropic, it is built for frontier reasoning at lower cost per task — Anthropic reports it more than doubling Opus 4.8 on Frontier-Bench v0.1, agentic coding — within 0.5% of Fable 5's peak CursorBench 3.2 score at half the cost per task (Anthropic's figures), computer use — surpasses Fable 5's best OSWorld 2.0 result at just over a third of the cost, and a native effort setting (low, medium, high, xhigh, max) that trades token cost against capability on a single model.
Its trade-offs are real: behind Mythos 5 on cybersecurity exploitation and biology research, by Anthropic's own account, all launch benchmarks are Anthropic-reported and not yet independently reproduced, no published SWE-Bench Verified score, so head-to-head coding comparisons rely on Anthropic's own benchmark suite, and fast mode's throughput costs double the base price ($10/$50 per 1M). At $5 in / $25 out per million tokens, it sits in the premium price band.
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: 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.
The bottom line for this matchup
Because Claude Opus 5 and Claude Opus 5.5 come from the same lab (Anthropic), they share the same training philosophy and ecosystem — the decision is purely tier vs. cost. Claude Opus 5.5 is the more capable, more recent option; the other earns its place only when its price or latency profile fits a specific job better. Most teams should default to Claude Opus 5.5 and drop down only with a concrete reason.
Frequently asked questions
Is Claude Opus 5 or Claude Opus 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 leans toward frontier reasoning at lower cost per task — anthropic reports it more than doubling opus 4.8 on frontier-bench v0.1 while 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, and that positioning usually predicts which feels better on your codebase.
Which is cheaper, Claude Opus 5 or Claude Opus 5.5?
Claude Opus 5.5 is cheaper — $5/$25 per 1M tokens vs $4/$20 per 1M tokens, roughly 1.3× apart on input.
Which has the bigger context window?
Both advertise 1M (~1,500 pages). Remember advertised ≠ usable: recall typically degrades before the ceiling.
Should I upgrade from Claude Opus 5 to Claude Opus 5.5?
Since both are Anthropic models, the newer one (Claude Opus 5.5) is usually the better default unless you need a specific cost or latency profile from the other.
Which is newer, Claude Opus 5 or Claude Opus 5.5?
Claude Opus 5.5 — released September 22, 2026, about 2 months after Claude Opus 5.
Claude Opus 5 vs Claude Opus 5.5
Anthropic · US | Anthropic · US · Updated June 2026
Quick verdict
Both are Anthropic models. Claude Opus 5.5 is the newer, generally stronger default; reach for Claude Opus 5 when a specific cost or latency profile matters more than the latest capabilities.
Claude Opus 5 and Claude Opus 5.5 are both Anthropic models, so the real question is not which lab to trust but which tier fits your workload and budget. Claude Opus 5 is anthropic's July 2026 flagship at $5/$25 with a 1M window and an effort dial — near-frontier quality pitched on cost per task, not raw peak. 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. Since both come from the same lab, the comparison below focuses on the tier-and-cost trade-offs that actually separate them.
Key differences at a glance
▸Price: nearly identical — $5/$25 per 1M tokens vs $4/$20 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: Claude Opus 5.5 is the newer model by about 2 months (released September 22, 2026), usually meaning fresher training data and capabilities.
Side-by-side specs
Spec
Claude Opus 5
Claude Opus 5.5
Provider
Anthropic (US)
Anthropic (US)
Released
July 24, 2026
September 22, 2026
Context window
1M (~1,500 pages)
1M tokens (~1,500 pages)
Price (in/out)
$5/$25 per 1M tokens
$4/$20 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
Frontier reasoning at lower cost per task — Anthropic reports it more than doubling Opus 4.8 on Frontier-Bench v0.1
Claude Opus 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
Agentic coding — within 0.5% of Fable 5's peak CursorBench 3.2 score at half the cost per task (Anthropic's figures)
Claude Opus 5
Claude Opus 5 lists agentic coding — within 0.5% of Fable 5's peak CursorBench 3.2 score at half the cost per task (Anthropic's figures) among its strengths; Claude Opus 5.5 does not.
Computer use — surpasses Fable 5's best OSWorld 2.0 result at just over a third of the cost
Claude Opus 5
Claude Opus 5 lists computer use — surpasses Fable 5's best OSWorld 2.0 result at just over a third of the cost among its strengths; Claude Opus 5.5 does not.
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 Claude Opus 5 ($5/$25 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
Claude Opus 5 is comparatively weak here — behind Mythos 5 on cybersecurity exploitation and biology research, by Anthropic's own account
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
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 runs cheaper at $4/$20 per 1M tokens.
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 Claude Opus 5, and on millions of tokens that margin decides the monthly bill.
Anyone whose priority is frontier reasoning at lower cost per task — anthropic reports it more than doubling opus 4.8 on frontier-bench v0.1
→ Claude Opus 5
It is specifically built for that.
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
That is its strongest area.
Claude Opus 5: where it fits
Anthropic's July 2026 flagship at $5/$25 with a 1M window and an effort dial — near-frontier quality pitched on cost per task, not raw peak. Released July 24, 2026 by Anthropic, it is built for frontier reasoning at lower cost per task — Anthropic reports it more than doubling Opus 4.8 on Frontier-Bench v0.1, agentic coding — within 0.5% of Fable 5's peak CursorBench 3.2 score at half the cost per task (Anthropic's figures), computer use — surpasses Fable 5's best OSWorld 2.0 result at just over a third of the cost, and a native effort setting (low, medium, high, xhigh, max) that trades token cost against capability on a single model.
Its trade-offs are real: behind Mythos 5 on cybersecurity exploitation and biology research, by Anthropic's own account, all launch benchmarks are Anthropic-reported and not yet independently reproduced, no published SWE-Bench Verified score, so head-to-head coding comparisons rely on Anthropic's own benchmark suite, and fast mode's throughput costs double the base price ($10/$50 per 1M). At $5 in / $25 out per million tokens, it sits in the premium price band.
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: 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.
The bottom line for this matchup
Because Claude Opus 5 and Claude Opus 5.5 come from the same lab (Anthropic), they share the same training philosophy and ecosystem — the decision is purely tier vs. cost. Claude Opus 5.5 is the more capable, more recent option; the other earns its place only when its price or latency profile fits a specific job better. Most teams should default to Claude Opus 5.5 and drop down only with a concrete reason.
Want both Claude Opus 5 and Claude Opus 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.
Is Claude Opus 5 or Claude Opus 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 leans toward frontier reasoning at lower cost per task — anthropic reports it more than doubling opus 4.8 on frontier-bench v0.1 while 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, and that positioning usually predicts which feels better on your codebase.
Which is cheaper, Claude Opus 5 or Claude Opus 5.5?
Claude Opus 5.5 is cheaper — $5/$25 per 1M tokens vs $4/$20 per 1M tokens, roughly 1.3× apart on input.
Which has the bigger context window?
Both advertise 1M (~1,500 pages). Remember advertised ≠ usable: recall typically degrades before the ceiling.
Should I upgrade from Claude Opus 5 to Claude Opus 5.5?
Since both are Anthropic models, the newer one (Claude Opus 5.5) is usually the better default unless you need a specific cost or latency profile from the other.
Which is newer, Claude Opus 5 or Claude Opus 5.5?
Claude Opus 5.5 — released September 22, 2026, about 2 months after Claude Opus 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.