AI model comparison
Step 3.5 Flash vs GPT-5 Nano
Pricing, context window, benchmarks, and features compared side by side. Or skip the guesswork and send one prompt to both.
StepFun
Step 3.5 Flash
Step 3.5 Flash is StepFun's most capable open-source foundation model.
- Input / 1M
- $0.10
- Output / 1M
- $0.30
- Context
- 262K
OpenAI
GPT-5 Nano
GPT-5-Nano is the smallest and fastest variant in the GPT-5 system, optimized for developer tools, rapid interactions, and ultra-low latency environments.
- Input / 1M
- $0.05
- Output / 1M
- $0.40
- Context
- 400K
At a glance
Quick verdict
How the two models stack up on the things people ask about most.
Lower price
GPT-5 Nano
1.2x cheaper for a typical chat
Higher intelligence score
Step 3.5 Flash
17 vs 13 on Artificial Analysis
Larger context window
GPT-5 Nano
400K vs 262K tokens
Newer release
Step 3.5 Flash
Released January 29, 2026
Benchmarks
Benchmark scores
Independent scores from Artificial Analysis. Higher is better.
Intelligence index
GPT-5 Nano13Coding index
GPT-5 NanoNot availableAgentic index
GPT-5 NanoNot availablePricing
Step 3.5 Flash vs GPT-5 Nano API pricing
Per-token API rates. Cheaper option highlighted.
| Metric | GPT-5 Nano | |
|---|---|---|
| Input tokensPer 1M tokens | $0.10 | $0.05 |
| Output tokensPer 1M tokens | $0.30 | $0.40 |
| Cached input (read)Per 1M tokens | Not available | $0.01 |
| Cache writePer 1M tokens | Not available | Not available |
| Web searchPer request | Not available | $0.01 |
What it costs in practice
Estimated cost per 1,000 requests at standard rates. Coding and long-document figures also show the cost when the input is already cached.
Chat message
2K in, 500 out
GPT-5 Nano$0.30Coding task
30K in, 4K out
GPT-5 Nano$3.10$1.75 cachedLong document summary
150K in, 2K out
GPT-5 Nano$8.30$1.55 cachedSpecs
Context window and capabilities
How much each model can read, how much it can write, and what it accepts as input.
| Metric | GPT-5 Nano | |
|---|---|---|
| Context window | 262K tokens | 400K tokens |
| Max output | 66K tokens | 128K tokens |
| Input types | Text | File, Image, Text |
| Output types | Text | Text |
| Reasoning effort levels | Not available | High, Medium, Low, Minimal |
| Default reasoning effort | Not available | Medium |
| Release date | January 29, 2026 | August 7, 2025 |
Features
Supported features
API features available for each model.
| Metric | GPT-5 Nano | |
|---|---|---|
| Tool calling | Supported | Supported |
| Structured outputs | Not supported | Supported |
| JSON mode | Not supported | Supported |
| Reasoning | Supported | Supported |
| Temperature | Supported | Not supported |
| Stop sequences | Not supported | Not supported |
| Deterministic seed | Not supported | Supported |
| Verbosity control | Not supported | Supported |
Keep exploring
More on these models
Other head-to-heads, the full model page, and the alternatives list for each model.
- Step 3.5 Flash vs Hy3
- Step 3.5 Flash vs DeepSeek V3.2
- Step 3.5 Flash vs Ling 3.0 Flash
- Step 3.5 Flash vs Step 3.7 Flash
- Step 3.5 Flash vs Qwen3.6 35B A3B
- Step 3.5 Flash vs Gemma 4 26B A4B
- Step 3.5 Flash vs DeepSeek V3.2 Exp
- Step 3.5 Flash vs Gemini 3.1 Flash Lite
- Step 3.5 Flash vs GLM 4.7 Flash
- Step 3.5 Flash vs Gemma 4 31B
GPT-5 NanoView full model details- GPT-5 Nano vs Gemini 2.5 Flash Lite
- GPT-5 Nano vs GPT-6 Luna Pro
- GPT-5 Nano vs gpt-oss-120b
- GPT-5 Nano vs Gemma 4 31B
- GPT-5 Nano vs Gemma 4 26B A4B
- GPT-5 Nano vs gpt-oss-20b
- GPT-5 Nano vs GPT-4o-mini
- GPT-5 Nano vs Qwen3 235B A22B Instruct 2507
- GPT-5 Nano vs DeepSeek V3.1
- GPT-5 Nano vs Mercury 2.5
- GPT-5 Nano vs Qwen3.5-9B
- GPT-5 Nano vs Nemotron 3.5 Lightning
- GPT-5 Nano vs GPT-4.1 Nano
- GPT-5 Nano vs Granite 4.2 8B
- GPT-5 Nano vs GLM 4.7 Flash
- GPT-5 Nano vs DeepSeek V3.2 Exp
- GPT-5 Nano vs Nemotron 3 Super
- GPT-5 Nano vs Mistral Small 4
- GPT-5 Nano vs Mercury 2
Our take
GPT-5 Nano is 1.2x cheaper for a typical chat. Step 3.5 Flash scores higher on the Artificial Analysis Intelligence Index (17 vs 13). GPT-5 Nano has the larger context window (400K vs 262K tokens). The right pick depends on your workload, so the quickest way to settle it is to send the same prompt to both and compare.
FAQ
Frequently asked questions
Is Step 3.5 Flash or GPT-5 Nano cheaper?
GPT-5 Nano is cheaper for a typical chat (2K input tokens and 500 output tokens). GPT-5 Nano costs $0.05 per 1M input tokens and $0.40 per 1M output tokens, while Step 3.5 Flash costs $0.10 per 1M input tokens and $0.30 per 1M output tokens.
Which has a bigger context window, Step 3.5 Flash or GPT-5 Nano?
GPT-5 Nano supports up to 400K tokens of context, compared with 262K for Step 3.5 Flash.
Is Step 3.5 Flash smarter than GPT-5 Nano?
On the Artificial Analysis Intelligence Index, Step 3.5 Flash scores 17 and GPT-5 Nano scores 13, putting Step 3.5 Flash ahead. Benchmarks don't capture everything, so the best test is running your own prompts through both.
Can I use Step 3.5 Flash and GPT-5 Nano at the same time?
Yes. Shortcut Chat sends one prompt to multiple models at once, so you can see Step 3.5 Flash and GPT-5 Nano answer side by side and keep the better response.
Why choose? Ask both.
Send one prompt to Step 3.5 Flash and GPT-5 Nano at the same time. Compare the answers side by side and keep the best one.