Both are Anthropic models. Claude Haiku 4.5 is the newer, generally stronger default; reach for Claude Sonnet 4.5 when a specific cost or latency profile matters more than the latest capabilities.
Claude Haiku 4.5 and Claude Sonnet 4.5 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 Claude Sonnet 4.5 is september 2025's coding state of the art at $3/$15 — still supported, but 200K-capped and twice superseded. 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 3× cheaper on input ($1/$5 per 1M tokens vs $3/$15 per 1M tokens) — meaningful once you are processing millions of tokens a month.
Context window: both advertise 200K (~300 pages). Tie on paper — test on your own long inputs, since usable recall varies by model.
Recency: Claude Haiku 4.5 is the newer model by about 16 days (released October 15, 2025), usually meaning fresher training data and capabilities.
Specifications
Spec
Claude Haiku 4.5
Claude Sonnet 4.5
Provider
Anthropic (US)
Anthropic (US)
Released
October 15, 2025
September 29, 2025
Context window
200K (~300 pages)
200K (~300 pages)
Price (in/out)
$1/$5 per 1M tokens
$3/$15 per 1M tokens
Open weight?
No — API only
No — API only
Modalities
text, image, code
text, image, code
SWE-Bench Verified
Not published
77.2%
MRCR v2 @ 1M
Not published
Not published
Who wins what
Fastest Claude model: 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 Sonnet 4.5 ($3/$15 per 1M tokens), and that gap compounds at volume.
Real-time interactions: Claude Haiku 4.5 — Anthropic's fastest, most compact model — built for speed and volume — and it is the newer of the two.
Agentic coding — 77.2% on SWE-Bench Verified, the best score any model had posted at its launch: Claude Sonnet 4.5 — Claude Sonnet 4.5 lists agentic coding — 77.2% on SWE-Bench Verified, the best score any model had posted at its launch among its strengths; Claude Haiku 4.5 does not.
Computer use and GUI automation (61.4% OSWorld at launch): Claude Sonnet 4.5 — Claude Sonnet 4.5 lists computer use and GUI automation (61.4% OSWorld at launch) among its strengths; Claude Haiku 4.5 does not.
Long-horizon autonomy — Anthropic reported 30+ hours of sustained focus on multi-step tasks: Claude Sonnet 4.5 — Claude Sonnet 4.5 lists long-horizon autonomy — Anthropic reported 30+ hours of sustained focus on multi-step tasks among its strengths; Claude Haiku 4.5 does not.
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.
Which should you pick?
A cost-sensitive startup shipping high volume: Claude Haiku 4.5 — At $1/$5 per 1M tokens it undercuts Claude Sonnet 4.5, and on millions of tokens that margin decides the monthly bill.
Anyone whose priority is fastest claude model: Claude Haiku 4.5 — It is specifically built for that.
Anyone whose priority is agentic coding — 77.2% on swe-bench verified, the best score any model had posted at its launch: Claude Sonnet 4.5 — 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, low-latency, high-volume API calls, real-time interactions, and cheapest Claude tier.
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 Sonnet 4.5: where it fits
September 2025's coding state of the art at $3/$15 — still supported, but 200K-capped and twice superseded. Released September 29, 2025 by Anthropic, it is built for agentic coding — 77.2% on SWE-Bench Verified, the best score any model had posted at its launch, computer use and GUI automation (61.4% OSWorld at launch), long-horizon autonomy — Anthropic reported 30+ hours of sustained focus on multi-step tasks, and tracking its own remaining token budget natively, which few models do.
Its trade-offs: superseded twice — Sonnet 4.6 and Sonnet 5 match or beat it at the same or lower price, capped at 200K since Anthropic retired its 1M beta in April 2026, while its successors ship 1M as standard, and missing the modern API surface: no adaptive thinking, no effort control, and half the max output of newer Sonnets. At $3 in / $15 out per million tokens, it sits in the mid price band.
The bottom line for this matchup
Because Claude Haiku 4.5 and Claude Sonnet 4.5 come from the same lab (Anthropic), they share the same training philosophy and ecosystem — the decision is purely tier vs. cost. Claude Haiku 4.5 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 Haiku 4.5 and drop down only with a concrete reason.
Frequently asked questions
Is Claude Haiku 4.5 or Claude Sonnet 4.5 better for coding?
Public SWE-Bench figures are not available for Claude Haiku 4.5, 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 Sonnet 4.5 leans toward agentic coding — 77.2% on swe-bench verified, the best score any model had posted at its launch, and that positioning usually predicts which feels better on your codebase.
Which is cheaper, Claude Haiku 4.5 or Claude Sonnet 4.5?
Claude Haiku 4.5 is cheaper — $1/$5 per 1M tokens vs $3/$15 per 1M tokens, roughly 3× apart on input.
Which has the bigger context window?
Both advertise 200K (~300 pages). Remember advertised ≠ usable: recall typically degrades before the ceiling.
Should I upgrade from Claude Sonnet 4.5 to Claude Haiku 4.5?
Since both are Anthropic models, the newer one (Claude Haiku 4.5) 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 Sonnet 4.5?
Claude Haiku 4.5 — released October 15, 2025, about 16 days after Claude Sonnet 4.5.
Claude Haiku 4.5 vs Claude Sonnet 4.5
Anthropic · US | Anthropic · US · Updated June 2026
Quick verdict
Both are Anthropic models. Claude Haiku 4.5 is the newer, generally stronger default; reach for Claude Sonnet 4.5 when a specific cost or latency profile matters more than the latest capabilities.
Claude Haiku 4.5 and Claude Sonnet 4.5 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 Sonnet 4.5 is september 2025's coding state of the art at $3/$15 — still supported, but 200K-capped and twice superseded. 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 3× cheaper on input ($1/$5 per 1M tokens vs $3/$15 per 1M tokens) — meaningful once you are processing millions of tokens a month.
▸Context window: both advertise 200K (~300 pages). Tie on paper — test on your own long inputs, since usable recall varies by model.
▸Recency: Claude Haiku 4.5 is the newer model by about 16 days (released October 15, 2025), usually meaning fresher training data and capabilities.
Side-by-side specs
Spec
Claude Haiku 4.5
Claude Sonnet 4.5
Provider
Anthropic (US)
Anthropic (US)
Released
October 15, 2025
September 29, 2025
Context window
200K (~300 pages)
200K (~300 pages)
Price (in/out)
$1/$5 per 1M tokens
$3/$15 per 1M tokens
Open weight?
No — API only
No — API only
Modalities
text, image, code
text, image, code
SWE-Bench Verified
Not published
77.2%
MRCR v2 @ 1M
Not published
Not published
Who wins what
Fastest Claude model
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 Sonnet 4.5 ($3/$15 per 1M tokens), and that gap compounds at volume.
Real-time interactions
Claude Haiku 4.5
Anthropic's fastest, most compact model — built for speed and volume — and it is the newer of the two.
Agentic coding — 77.2% on SWE-Bench Verified, the best score any model had posted at its launch
Claude Sonnet 4.5
Claude Sonnet 4.5 lists agentic coding — 77.2% on SWE-Bench Verified, the best score any model had posted at its launch among its strengths; Claude Haiku 4.5 does not.
Computer use and GUI automation (61.4% OSWorld at launch)
Claude Sonnet 4.5
Claude Sonnet 4.5 lists computer use and GUI automation (61.4% OSWorld at launch) among its strengths; Claude Haiku 4.5 does not.
Long-horizon autonomy — Anthropic reported 30+ hours of sustained focus on multi-step tasks
Claude Sonnet 4.5
Claude Sonnet 4.5 lists long-horizon autonomy — Anthropic reported 30+ hours of sustained focus on multi-step tasks among its strengths; Claude Haiku 4.5 does not.
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.
Which should you pick?
A cost-sensitive startup shipping high volume
→ Claude Haiku 4.5
At $1/$5 per 1M tokens it undercuts Claude Sonnet 4.5, and on millions of tokens that margin decides the monthly bill.
Anyone whose priority is fastest claude model
→ Claude Haiku 4.5
It is specifically built for that.
Anyone whose priority is agentic coding — 77.2% on swe-bench verified, the best score any model had posted at its launch
→ Claude Sonnet 4.5
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, low-latency, high-volume API calls, real-time interactions, and cheapest Claude tier.
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 Sonnet 4.5: where it fits
September 2025's coding state of the art at $3/$15 — still supported, but 200K-capped and twice superseded. Released September 29, 2025 by Anthropic, it is built for agentic coding — 77.2% on SWE-Bench Verified, the best score any model had posted at its launch, computer use and GUI automation (61.4% OSWorld at launch), long-horizon autonomy — Anthropic reported 30+ hours of sustained focus on multi-step tasks, and tracking its own remaining token budget natively, which few models do.
Its trade-offs: superseded twice — Sonnet 4.6 and Sonnet 5 match or beat it at the same or lower price, capped at 200K since Anthropic retired its 1M beta in April 2026, while its successors ship 1M as standard, and missing the modern API surface: no adaptive thinking, no effort control, and half the max output of newer Sonnets. At $3 in / $15 out per million tokens, it sits in the mid price band.
The bottom line for this matchup
Because Claude Haiku 4.5 and Claude Sonnet 4.5 come from the same lab (Anthropic), they share the same training philosophy and ecosystem — the decision is purely tier vs. cost. Claude Haiku 4.5 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 Haiku 4.5 and drop down only with a concrete reason.
Want both Claude Haiku 4.5 and Claude Sonnet 4.5 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 Sonnet 4.5 better for coding?
Public SWE-Bench figures are not available for Claude Haiku 4.5, 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 Sonnet 4.5 leans toward agentic coding — 77.2% on swe-bench verified, the best score any model had posted at its launch, and that positioning usually predicts which feels better on your codebase.
Which is cheaper, Claude Haiku 4.5 or Claude Sonnet 4.5?
Claude Haiku 4.5 is cheaper — $1/$5 per 1M tokens vs $3/$15 per 1M tokens, roughly 3× apart on input.
Which has the bigger context window?
Both advertise 200K (~300 pages). Remember advertised ≠ usable: recall typically degrades before the ceiling.
Should I upgrade from Claude Sonnet 4.5 to Claude Haiku 4.5?
Since both are Anthropic models, the newer one (Claude Haiku 4.5) 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 Sonnet 4.5?
Claude Haiku 4.5 — released October 15, 2025, about 16 days after Claude Sonnet 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.