Both are Anthropic models. Claude Opus 5.5 is the newer, generally stronger default; reach for Claude Haiku 4.5 when its lower price or a specific cost or latency profile matters more than the latest capabilities.
Claude Haiku 4.5 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 Haiku 4.5 is anthropic's fastest, most compact model — built for speed and volume. 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: Claude Haiku 4.5 is about 4× cheaper on input ($1/$5 per 1M tokens vs $4/$20 per 1M tokens) — meaningful once you are processing millions of tokens a month.
Context window: Claude Opus 5.5 holds 5× more — 1M tokens (~1,500 pages) vs 200K (~300 pages). But effective recall usually fades long before the advertised ceiling, so the bigger number only helps if the model reasons over it.
Recency: Claude Opus 5.5 is the newer model by about 11 months (released September 22, 2026), usually meaning fresher training data and capabilities.
Specifications
Spec
Claude Haiku 4.5
Claude Opus 5.5
Provider
Anthropic (US)
Anthropic (US)
Released
October 15, 2025
September 22, 2026
Context window
200K (~300 pages)
1M tokens (~1,500 pages)
Price (in/out)
$1/$5 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
73.3%
Not published
MRCR v2 @ 1M
Not published
Not published
Who wins what
Fastest Claude model: Claude Haiku 4.5 — Claude Opus 5.5 is comparatively weak here — 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
Near-frontier coding for its tier — 73.3% on SWE-Bench Verified: Claude Haiku 4.5 — Anthropic's fastest, most compact model — built for speed and volume — and it runs cheaper at $1/$5 per 1M tokens.
Low-latency, high-volume API calls: Claude Haiku 4.5 — At $1/$5 per 1M tokens it undercuts Claude Opus 5.5 ($4/$20 per 1M tokens), and that gap compounds at volume.
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 carries the larger 1M tokens context.
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 Haiku 4.5 is comparatively weak here — not for deep reasoning
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 — Its 1M tokens window holds about 5× more than Claude Haiku 4.5's 200K in a single prompt.
Lowest cost at scale: Claude Haiku 4.5 — At $1/$5 per 1M tokens, it is the cheaper of the two — the gap dominates the bill on high-volume workloads.
Largest single-prompt input: Claude Opus 5.5 — Its 1M tokens window is about 5× larger than Claude Haiku 4.5's 200K, fitting roughly 1,500 pages in one prompt.
Which should you pick?
A cost-sensitive startup shipping high volume: Claude Haiku 4.5 — At $1/$5 per 1M tokens it undercuts Claude Opus 5.5, and on millions of tokens that margin decides the monthly bill.
Someone analysing very long documents or codebases: Claude Opus 5.5 — Larger 1M tokens window fits more in one prompt.
Anyone whose priority is fastest claude model: Claude Haiku 4.5 — 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 Haiku 4.5: where it fits
Anthropic's fastest, most compact model — built for speed and volume. Released October 15, 2025 by Anthropic, it is built for fastest Claude model, near-frontier coding for its tier — 73.3% on SWE-Bench Verified, low-latency, high-volume API calls, and cheapest Claude tier at $1/$5.
Its trade-offs are real: smallest context in the family (200K), and not for deep reasoning. At $1 in / $5 out per million tokens, it sits in the budget 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 Haiku 4.5 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 Haiku 4.5 or Claude Opus 5.5 better for coding?
Public SWE-Bench figures are not available for Claude Opus 5.5, so the honest test is your own repository — run an identical real bug through both. By design, Claude Haiku 4.5 leans toward fastest claude model 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 Haiku 4.5 or Claude Opus 5.5?
Claude Haiku 4.5 is cheaper — $1/$5 per 1M tokens vs $4/$20 per 1M tokens, roughly 4× apart on input.
Which has the bigger context window?
Claude Opus 5.5 — 1M tokens vs 200K, about 5× larger. Useful only if the model actually reasons over the full window, which not all do.
Should I upgrade from Claude Haiku 4.5 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 Haiku 4.5 or Claude Opus 5.5?
Claude Opus 5.5 — released September 22, 2026, about 11 months after Claude Haiku 4.5.
Claude Haiku 4.5 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 Haiku 4.5 when its lower price or a specific cost or latency profile matters more than the latest capabilities.
Claude Haiku 4.5 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 Haiku 4.5 is anthropic's fastest, most compact model — built for speed and volume. 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: Claude Haiku 4.5 is about 4× cheaper on input ($1/$5 per 1M tokens vs $4/$20 per 1M tokens) — meaningful once you are processing millions of tokens a month.
▸Context window: Claude Opus 5.5 holds 5× more — 1M tokens (~1,500 pages) vs 200K (~300 pages). But effective recall usually fades long before the advertised ceiling, so the bigger number only helps if the model reasons over it.
▸Recency: Claude Opus 5.5 is the newer model by about 11 months (released September 22, 2026), usually meaning fresher training data and capabilities.
Side-by-side specs
Spec
Claude Haiku 4.5
Claude Opus 5.5
Provider
Anthropic (US)
Anthropic (US)
Released
October 15, 2025
September 22, 2026
Context window
200K (~300 pages)
1M tokens (~1,500 pages)
Price (in/out)
$1/$5 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
73.3%
Not published
MRCR v2 @ 1M
Not published
Not published
Who wins what
Fastest Claude model
Claude Haiku 4.5
Claude Opus 5.5 is comparatively weak here — 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
Near-frontier coding for its tier — 73.3% on SWE-Bench Verified
Claude Haiku 4.5
Anthropic's fastest, most compact model — built for speed and volume — and it runs cheaper at $1/$5 per 1M tokens.
Low-latency, high-volume API calls
Claude Haiku 4.5
At $1/$5 per 1M tokens it undercuts Claude Opus 5.5 ($4/$20 per 1M tokens), and that gap compounds at volume.
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 carries the larger 1M tokens context.
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 Haiku 4.5 is comparatively weak here — not for deep reasoning
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
Its 1M tokens window holds about 5× more than Claude Haiku 4.5's 200K in a single prompt.
Lowest cost at scale
Claude Haiku 4.5
At $1/$5 per 1M tokens, it is the cheaper of the two — the gap dominates the bill on high-volume workloads.
Largest single-prompt input
Claude Opus 5.5
Its 1M tokens window is about 5× larger than Claude Haiku 4.5's 200K, fitting roughly 1,500 pages in one prompt.
Which should you pick?
A cost-sensitive startup shipping high volume
→ Claude Haiku 4.5
At $1/$5 per 1M tokens it undercuts Claude Opus 5.5, and on millions of tokens that margin decides the monthly bill.
Someone analysing very long documents or codebases
→ Claude Opus 5.5
Larger 1M tokens window fits more in one prompt.
Anyone whose priority is fastest claude model
→ Claude Haiku 4.5
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 Haiku 4.5: where it fits
Anthropic's fastest, most compact model — built for speed and volume. Released October 15, 2025 by Anthropic, it is built for fastest Claude model, near-frontier coding for its tier — 73.3% on SWE-Bench Verified, low-latency, high-volume API calls, and cheapest Claude tier at $1/$5.
Its trade-offs are real: smallest context in the family (200K), and not for deep reasoning. At $1 in / $5 out per million tokens, it sits in the budget 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 Haiku 4.5 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 Haiku 4.5 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 Haiku 4.5 or Claude Opus 5.5 better for coding?
Public SWE-Bench figures are not available for Claude Opus 5.5, so the honest test is your own repository — run an identical real bug through both. By design, Claude Haiku 4.5 leans toward fastest claude model 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 Haiku 4.5 or Claude Opus 5.5?
Claude Haiku 4.5 is cheaper — $1/$5 per 1M tokens vs $4/$20 per 1M tokens, roughly 4× apart on input.
Which has the bigger context window?
Claude Opus 5.5 — 1M tokens vs 200K, about 5× larger. Useful only if the model actually reasons over the full window, which not all do.
Should I upgrade from Claude Haiku 4.5 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 Haiku 4.5 or Claude Opus 5.5?
Claude Opus 5.5 — released September 22, 2026, about 11 months after Claude Haiku 4.5.
Specifications and benchmarks reflect publicly reported figures as of June 2026 and may change as providers release updates. Always verify on your own workload.