Model comparison
GPT-5.5 Instant vs GPT-5.3 Instant
- Input
- $5.00
- Output
- $30.00
- Context
- 1.05M
- Released
- 2026-05-05
- Input
- $1.75 / 1M tokens
- Output
- $14.00 / 1M tokens
- Context
- 128K
- Released
- 2026-03-03
GPT-5.3 Instant is cheaper on input tokens ($1.8 vs $5 per 1M, 2.9×); GPT-5.5 Instant has the larger context window (1.05M vs 128K).
Specs and pricing side by side
| Spec | GPT-5.5 Instant | GPT-5.3 Instant |
|---|---|---|
| Maker | OpenAI | OpenAIsame |
| Released | 2026-05-05 | 2026-03-03 |
| Context window | 1.05M | 128K |
| Max output | 128K | 16,384 tokens |
| Input price | $5.00 | $1.75 / 1M tokens |
| Output price | $30.00 | $14.00 / 1M tokens |
| Parameters | Undisclosed | Undisclosedsame |
| License | Proprietary | Proprietarysame |
| Weights | API only | API onlysame |
| Modalities | Text, Vision | Text, Visionsame |
| Knowledge cutoff | 2025-12-01 | 2025-08-31 |
Benchmarks both models report
These two models have no benchmark in common in our registry, so there is no like-for-like score to compare. See each model’s own results: GPT-5.5 Instant, GPT-5.3 Instant.
Which one should you pick?
Pick GPT-5.5 Instant if…
- You need the longer context (1.05M vs 128K).
- Your use case is: everyday ChatGPT conversation, drafting, and quick Q&A.
Pick GPT-5.3 Instant if…
- Cost matters: input tokens cost 2.9× less ($1.8 vs $5 per 1M).
- Your use case is: everyday ChatGPT conversation and quick question-answering.
FAQ
Which is better, GPT-5.5 Instant or GPT-5.3 Instant?
GPT-5.3 Instant is cheaper on input tokens ($1.8 vs $5 per 1M, 2.9×); GPT-5.5 Instant has the larger context window (1.05M vs 128K). The better pick depends on whether you value benchmark scores, price per token, context length or openness for your workload.
How much cheaper is GPT-5.3 Instant?
GPT-5.5 Instant: $5.00 input, $30.00 output. GPT-5.3 Instant: $1.75 / 1M tokens input, $14.00 / 1M tokens output (list API prices as published by each maker).
What are the context windows of GPT-5.5 Instant and GPT-5.3 Instant?
GPT-5.5 Instant offers 1.05M with up to 128K output; GPT-5.3 Instant offers 128K with up to 16,384 tokens output.
Is GPT-5.5 Instant newer than GPT-5.3 Instant?
GPT-5.5 Instant was released 2026-05-05; GPT-5.3 Instant was released 2026-03-03.