GPT-5.5 for most accurate llms
GPT-5.5 is the #1 pick on LLMDex's most accurate llms ranking out of 5 models we track for this use case. Below, the specific reasons it slots where it does, and when you should reach for an alternative.
Updated
At a glance
- Rank
- #1 of 5
- Context
- 400K tokens
- Output / 1M
- Pricing not published
- Released
- Mar 2026
Why GPT-5.5 fits this task
Three things about GPT-5.5 that map directly onto what this task rewards: Strong end-to-end agent performance across SWE-bench and GAIA; Polished multimodal grounding on screenshots and charts. Beyond the task-specific fit, GPT-5.5 also brings industry-leading tool-use and function-calling reliability and wide ecosystem support, chatgpt, realtime api, responses api, both of which compound when the workload broadens.
The criteria this task rewards
LLMDex ranks most accurate llms on 5 criteria , these are the axes the ranking uses, in priority order:
- MMLU-Pro composite score
- GPQA Diamond
- SWE-bench Verified
- Average across multi-skill leaderboards
- Stability across reruns (eval reproducibility)
How GPT-5.5 scores on each axis
Where GPT-5.5 costs you: pricing premium vs. open-weight alternatives. For most teams this is acceptable on this workload, the value of the strengths above outweighs the cost. For cost-bound workloads or teams with strict latency budgets, run an eval against the next two ranked models on real data before committing.
Strengths that pay off here
- Industry-leading tool-use and function-calling reliability
- Strong end-to-end agent performance across SWE-bench and GAIA
- Wide ecosystem support, ChatGPT, Realtime API, Responses API
- Polished multimodal grounding on screenshots and charts
Tracked weaknesses
- Pricing premium vs. open-weight alternatives
- Output cost climbs fast on agent loops with many reasoning tokens
- Stricter content policy than some peers for creative work
When to pick something else
If you have a binding constraint that GPT-5.5 doesn't satisfy, pricing, license, regional availability, modality coverage, the next-best pick on this task is Claude Opus 4.7 from Anthropic. Anthropic's mid-2026 flagship, ahead on SWE-bench, agent reliability, and writing quality.
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Other models for most accurate llms
- Claude Opus 4.7 for most accurate llms
Anthropic's mid-2026 flagship, ahead on SWE-bench, agent reliability, and writing quality.
Read guide - Gemini 3 Pro for most accurate llms
Google's late-2025 flagship, set new benchmarks on long-context, vision, and reasoning at competitive pricing.
Read guide - o3 for most accurate llms
OpenAI's flagship reasoning model, set the bar for hard math, GPQA, and agent benchmarks in 2025.
Read guide - Claude Sonnet 4.6 for most accurate llms
Anthropic's mid-tier 4.6 release, the workhorse model behind most production Anthropic deployments.
Read guide
GPT-5.5 for other use cases
Direct comparisons
Frequently asked
Is GPT-5.5 good for most accurate llms?
GPT-5.5 is ranked #1 on LLMDex's most accurate llms list. OpenAI's mid-cycle GPT-5 refresh, improved reasoning, tool use, and multimodal grounding over the 2025 launch.How much does GPT-5.5 cost for most accurate llms?
OpenAI has not published per-token pricing for GPT-5.5 at the time of writing.What's a cheaper alternative to GPT-5.5 for most accurate llms?
The next ranked model on this task is Claude Opus 4.7. Compare both before committing.When should I NOT use GPT-5.5 for most accurate llms?
Tracked weakness: Pricing premium vs. open-weight alternatives. If that constraint is binding for your workload, the next-ranked model on this task is the safer pick.
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