GPT-5 vs GPT-5.5
Pricing, benchmarks, and use case comparison
Verdict
Our pick: GPT-5.5Pick GPT-5 for strong reasoning at a much lower price and solid math; pick GPT-5.5 for OpenAI's newer frontier default with better agentic coding, a larger context, and fresher knowledge.
Specs comparison
| GPT-5 | GPT-5.5 | |
|---|---|---|
| Provider | OpenAI | OpenAI |
| Type | Closed source | Closed source |
| Context window | ✓400,000 tokens (128,000 max output) | 1,050,000 tokens (128,000 max output) |
| Input / 1M tokens | ✓$1.25 | $5.00 |
| Output / 1M tokens | $10.00 | $30.00 |
| Release date | 2025-08 | 2026-04 |
Benchmarks
| Benchmark | GPT-5 | GPT-5.5 |
|---|---|---|
| SWE-bench Verified | 74.9% | ✓82.6% |
| AIME 2025 | 94.6% | - |
| GPQA (GPT-5 pro) | 88.4% | - |
| SWE-bench Pro | - | 58.6% |
Scores sourced from official provider release posts and independent benchmark aggregators.
Capability and benchmarks
GPT-5.5 is the stronger, newer flagship: 82.6% SWE-bench Verified and 58.6% SWE-bench Pro, with capability scores of coding 93 and reasoning 92. GPT-5 (August 2025) posts 74.9% SWE-bench Verified but remains excellent at math (94.6% AIME 2025 without tools) and reasoning (coding 88, reasoning 90). For agentic coding and end-to-end task completion, GPT-5.5 is the upgrade; for competition math specifically, GPT-5 is still very strong.
Price and context
Price is where GPT-5 shines: $1.25 input / $10 output per 1M (cached input $0.125) versus GPT-5.5's $5/$30. Context favors GPT-5.5, which offers a 1,050,000-token window against GPT-5's 400,000, though GPT-5.5 adds a surcharge above 272K input tokens. GPT-5.5 also has a fresher knowledge cutoff (December 1, 2025 vs September 30, 2024).
Which to pick
- Pick GPT-5 for budget-friendly frontier reasoning, math and STEM work, and existing tuned GPT-5 pipelines where its 4x-cheaper input cost matters.
- Pick GPT-5.5 for new projects: stronger agentic coding, a much larger context window, fresher knowledge, and OpenAI's own recommendation as the default frontier model.
Which should you choose?
Choose GPT-5 if...
- →You want strong reasoning at the lowest frontier-model price
- →Existing GPT-5-based systems that are already tuned and validated
- →General coding, math, and reasoning workloads on a budget
Choose GPT-5.5 if...
- →Complex professional coding, data analysis, and multi-tool agentic workflows
- →Long-document or large-codebase tasks needing a 1M+ context window
- →You want OpenAI's recommended default frontier model for new projects