AllocateGPT-5.5 vs Claude Opus 4.8
On provider list prices, Claude Opus 4.8 costs $5 per million input tokens against $5 for GPT-5.5: effectively level. Output is $25 against $30 (1.2x).
GPT-5.5
Claude Opus 4.8Specifications and provider list prices from the Allocate catalog, checked 2026-07-21.
What the numbers say
Take 1,000,000 requests a month at 1,200 input and 350 output tokens each. That workload costs $14,750 a month on Claude Opus 4.8 and $16,500 on GPT-5.5 at list: a gap of $1,750.
GPT-5.5 reads 400K tokens per request against 200K for Claude Opus 4.8, 2.0x the window. That decides which one can take whole documents without splitting them.
Choose Claude Opus 4.8 for
- Hardest reasoning problems
- High-stakes analysis
- Escalation tier for agents
Common questions
Which is cheaper, GPT-5.5 or Claude Opus 4.8?
Claude Opus 4.8, on this workload shape. At list prices it is $5/$25 per million tokens in and out against $5/$30 for GPT-5.5. Billed on Allocate: $5.35/$26.75 against $5.35/$32.10.
Which has the bigger context window?
GPT-5.5: 400,000 tokens (400K) against 200,000 (200K) for Claude Opus 4.8.
Can I fine-tune GPT-5.5 or Claude Opus 4.8?
No. Both are closed models served over API. If you want a model you can train and own, start from an open-weights base in the catalog.
Related comparisons
Run the numbers on your workload
Or don’t choose. On Allocate a route name is the contract: point yours at one model today, swap to the other tomorrow, and compare them on your live traffic with per-token metering.