Anthropic API replaces Sonnet 4.5 with 4.6 at same price point
What happened
Between the Feb 9, 2026 and Feb 18, 2026 captures of Anthropic's pricing page, Pulse recorded 2 changes: Sonnet 4.5 retired from current models and moved to legacy section; now listed as first legacy model (previously Opus 4.5 was first legacy); Sonnet 4.6 introduced to current API models replacing Sonnet 4.5 at same price point ($3 input / $15 output per MTok). Pulse files it as a packaging change (new plan). Pulse's latest capture (Nov 9, 2026) lists Haiku 4.5 at $5 per MTok output + $1.25 per MTok cache write, Sonnet 5 at $2 per MTok input + $10 per MTok output, Opus 5 at $6.25 per MTok cache write + $0.50 per MTok cache read, Fable 5 at $12.50 per MTok cache write + $1 per MTok cache read and Opus 4.8 at $6.25 per MTok cache write + $5 per MTok input.
Anthropic's previous recorded change was "Anthropic API rolls out tiered pricing for Opus 4.6 by context length" (week of Feb 2, 2026). Before that Pulse recorded "Anthropic API unveils Opus 4.6 pricing with new >200K token tiers" (Feb 9, 2026), "Anthropic API ends holiday promo, drops 2x usage boost for paid subscribers" (week of Dec 29, 2025) and "Anthropic API Cuts Flagship Opus Model Prices by 67% in Major Update to Version 4.5, Launching New Pricing Structure" (Jan 10, 2026). Anthropic has been tracked since 2024-11-17.
In the same window X, OpenAI and Microsoft also changed their AI & Machine Learning pricing pages. Those moves are listed further down, and the Pulse Agent can compare them side by side.
- ChangedSonnet 4.5Plancurrent models and movedlegacy section
- AddedSonnet 4.6, Sonnet 4.5PlanNot listedSonnet 4.6
| Plan | Field | Before | After | Change |
|---|---|---|---|---|
| Sonnet 4.5 | Plan | current models and moved | legacy section | Changed |
| Sonnet 4.6, Sonnet 4.5 | Plan | Not listed | Sonnet 4.6 | Added |
Values as written on Anthropic's public pricing page in the two captures Pulse compared; where the page states no number, the cells give the wording before and after.
Evidence
The two captures Pulse comparedFull-page captures of Anthropic's pricing page (anthropic.com) from Feb 9, 2026 and Feb 18, 2026; the change is marked around the middle of the page, where "current models and moved" becomes "legacy section".
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Anthropic, the last 90 days
Full history- Apr 21, 2026PackagingAnthropic API launches Managed Agents at $0.08 per session-hour of runtime
- Apr 4, 2026PackagingAnthropic API Drops Tiered Pricing for Sonnet 4.6, Goes Flat Rate
- Mar 16, 2026PackagingAnthropic API simplifies pricing, removes volume-based tiers
- Feb 18, 2026PackagingAnthropic API replaces Sonnet 4.5 with 4.6 at same price point This change
- Week of Feb 2, 2026PackagingAnthropic API rolls out tiered pricing for Opus 4.6 by context length
- Feb 9, 2026PackagingAnthropic API unveils Opus 4.6 pricing with new >200K token tiers
- Week of Dec 29, 2025PackagingAnthropic API ends holiday promo, drops 2x usage boost for paid subscribers
- Jan 10, 2026PackagingAnthropic API Cuts Flagship Opus Model Prices by 67% in Major Update to Version 4.5, Launching New Pricing Structure
Across AI & Machine Learning in the same window
All AI & Machine Learning changes- XFeb 18X adds real-time voice AI, drops structured outputs from API
- OpenAIFeb 18OpenAI API shifts Containers to per-session billing starting March 31
- MicrosoftJan 20Microsoft Copilot Transforms Copilot Pro into Family-Oriented 365 Premium Subscription with Enhanced AI Features and Increased Cloud Storage
Questions about this change
Did Anthropic raise prices in February 2026?
No list-price increase was recorded between Feb 9, 2026 and Feb 18, 2026. The change Pulse detected was a packaging change: new plan.
What changed on Anthropic's pricing page between Feb 9, 2026 and Feb 18, 2026?
Sonnet 4.5 plan: current models and moved → legacy section, changed; Sonnet 4.6, Sonnet 4.5 plan added: Sonnet 4.6. Pulse compared the captures it took on Feb 9, 2026 and Feb 18, 2026; the before/after table above lists each item as written on the page.
How often does Anthropic change its pricing?
Pulse recorded 4 other pricing-page changes for Anthropic in the 90 days before this one; the previous change was "Anthropic API rolls out tiered pricing for Opus 4.6 by context length" in the week of Feb 2, 2026; Anthropic has been tracked since 2024-11-17.