Comparison · Updated Sep 19, 2026
Claude Sonnet 4.5 vs GPT-4o
A 2025 coding-focused model against the 2024 fast multimodal workhorse: Sonnet 4.5 is far stronger on software work, GPT-4o is cheaper and quicker for everyday chat.
At a glance
| Spec | Claude Sonnet 4.5 | GPT-4o |
|---|---|---|
| Released | Sep 29, 2025 | May 13, 2024 |
| Context window | 200K tokens | 128K tokens |
| Licence | Closed / API | Closed / API |
| Inputs | text, image | text, image, audio |
| Public API | Yes | Yes |
Model A
Claude Sonnet 4.5
Anthropic's coding- and agent-focused flagship in the Claude 4 family.
Sep 29, 2025
Model B
GPT-4o
Omni-model unifying text, vision and audio in a single network with realtime capabilities.
May 13, 2024
Differences
| Attribute | Claude Sonnet 4.5 | GPT-4o |
|---|---|---|
| Released | September 2025 | May 2024 |
| Context window | 200K tokens | 128K tokens |
| Inputs | Text, image | Text, image, audio |
| Coding strength | High | Moderate |
| Best for | Software engineering, agents | Fast multimodal chat |
Verdict
Sonnet 4.5 for software engineering and long agent runs. GPT-4o for cost-sensitive, high-volume, multimodal chat.
Analysis
Generational gap
Claude Sonnet 4.5 (September 2025) is a full generation newer. It holds long agentic coding sessions, edits multi-file projects and follows complex instructions more reliably than GPT-4o.
Where GPT-4o still fits
GPT-4o remains attractive for latency-sensitive and voice work, and for high-volume tasks where per-token cost dominates.
Context and inputs
Both accept images; Claude offers 200K tokens against GPT-4o''s 128K. GPT-4o adds native audio.
Frequently asked
- Is Claude Sonnet 4.5 worth the extra cost?
- For software work and long agent runs, usually yes. For simple chat or transcription-style tasks, GPT-4o is more economical.