LLM Toolkit Model comparison
GPT-5 vs Claude Opus 5
Verified pricing, context windows and real-workload costs for both models — computed from official provider rates as of 2026-08-26.
Cheaper input
GPT-5
$1.25 /1M in
Cheaper output
GPT-5
$10.00 /1M out
Bigger context
Claude Opus 5
1M tokens
Head to head
| Spec | GPT-5 | Claude Opus 5 |
|---|---|---|
| Input / 1M tokens | $1.25 | $5.00 |
| Cached input / 1M | $0.13 | $0.5 |
| Output / 1M tokens | $10.00 | $25.00 |
| Context window | 400K | 1M |
| Provider | OpenAI | Anthropic |
| Price verified | 2026-08-26 | 2026-08-26 |
Monthly cost at three real workloads
| Workload | GPT-5 | Claude Opus 5 | Winner |
|---|---|---|---|
| Side-project chatbot 30K req · 2,000 in / 500 out · 40% cached | $198.00/mo | $567.00/mo | GPT-5 |
| Coding agent 500K req · 12,000 in / 1,500 out · 70% cached | $10,275/mo | $29,850/mo | GPT-5 |
| Bulk extraction 2,000K req · 800 in / 120 out · 20% cached | $4,040/mo | $12,560/mo | GPT-5 |
Computed from list prices verified 2026-08-26. Cache savings blend normal and cached input rates by the hit rate; models without published cached rates use the base input price. Adjust every parameter yourself on the API Cost Calculator.
Pick GPT-5 if…
- Input cost dominates your bill — it charges $1.25 per 1M input vs $5.00.
- Your documents fit its 400K window comfortably.
- You run repeat-context workloads — cached input at $0.13 per 1M is the better deal.
Pick Claude Opus 5 if…
- Output-heavy agent loops favor its $25.00 output rate.
- You need 1M tokens of context for large codebases or document sets.
- You want cheaper total spend at your exact volumes — verify with the calculator above.
Frequently asked questions
Is GPT-5 cheaper than Claude Opus 5?
GPT-5 is cheaper on input at $1.25 per 1M tokens vs $5.00 — input pricing is 4.0× less expensive. On output, GPT-5 wins at $10.00 vs $25.00. At a balanced workload (100K requests, 2K in / 500 out), GPT-5 runs $750.00/mo vs $2,250/mo — a 3.0× difference.
GPT-5 vs Claude Opus 5: which has the bigger context window?
Claude Opus 5, with 1M tokens vs 400K — 2.5× more room. Filling Claude Opus 5's window once costs $5.00 at list price, vs $0.500 for the smaller window.
Should I switch from GPT-5 to Claude Opus 5?
Switch if your bottleneck matches Claude Opus 5's strengths: the larger 1M context and its pricing profile. Stay on GPT-5 if input cost dominates your bill — GPT-5 charges $1.25 per 1M in. Test both with your real token counts before committing.
Keep comparing
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- Gemini 3.5 Flash vs GPT-5 mini
- Gemini 3.5 Flash vs Claude Sonnet 5
- Claude Opus 5 vs Gemini 3.5 Flash
- GPT-5 vs GPT-5 mini
- GPT-5 mini vs GPT-5 nano
Or measure your real usage with the AI Token Counter and browse all rates on the Pricing Comparison.