GPT-5 vs GPT-5.5 Instant
Pricing, benchmarks, and use case comparison
Quick take
- •GPT-5 leads on 1 of 1 shared benchmarks, including AIME 2025 (94.6% vs 81.2).
- •GPT-5 is meaningfully stronger at cost efficiency (88 vs 70 on our capability index).
- •GPT-5.5 Instant is meaningfully stronger at speed (92 vs 68).
- •GPT-5 is 75% cheaper on input tokens, which compounds fast on high-volume or agentic workloads.
- •GPT-5.5 Instant has a 1050000 context window vs 400,000 tokens (128,000 max output) - better for whole-repo or long-document work.
Specs comparison
| GPT-5 | GPT-5.5 Instant | |
|---|---|---|
| Provider | OpenAI | OpenAI |
| Type | Closed source | Closed source |
| Context window | 400,000 tokens (128,000 max output) | ✓1050000 |
| Input / 1M tokens | ✓$1.25 | 5.00 |
| Output / 1M tokens | $10.00 | 30.00 |
| Release date | 2025-08 | 2026-05 |
Benchmarks
| Benchmark | GPT-5 | GPT-5.5 Instant |
|---|---|---|
| SWE-bench Verified | 74.9% | - |
| AIME 2025 | ✓94.6% | 81.2 |
| GPQA (GPT-5 pro) | 88.4% | - |
| Terminal-Bench 2.0 | - | 82.7 |
| FrontierMath Tier 1–3 | - | 51.7 |
Scores sourced from official provider release posts and independent benchmark aggregators.
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 Instant if...
- →Interactive chat and everyday assistant tasks where responsiveness matters most
- →High-volume, latency-sensitive workloads that do not need deep reasoning
- →General questions, drafting, and summarization at speed