GPT-5.1 vs CustomGPT
A detailed comparison to help you choose the right AI tool for your needs.
Our Pick
GPT-5.1 Instant
GPT-5.1 Instant edges out CustomGPT with superior overall performance and features that make it the better choice for most users.
Try GPT-5.1Feature Comparison
Feature
GPT-5.1
CustomGPT
Ratings
Overall Rating
4.7
4.4
Coding
4.5
-
Writing
4.6
4.0
Reasoning
4.8
4.0
Speed
4.8
4.5
Value
4.6
4.3
Pricing
Monthly Price
$20
$49
Free Tier
Input (per 1M tokens)
$2.5
-
Output (per 1M tokens)
$10
-
Features
Context Window
128K
100K
Vision/Images
Audio
Video
Code Generation
AI Agents
GPT-5.1 Instant
Pros
- Fast responses with adaptive reasoning
- New personalization presets
- Strong math and coding improvements
- Multimodal (text, image, audio)
- Free tier available
Cons
- Coding not as strong as Claude Opus
- Can be verbose
- Writing style less natural than Claude
CustomGPT
Pros
- No-code chatbot builder
- Train on your own data
- Great for customer service
- Easy to deploy on websites
- MIT case study validation
Cons
- Not for coding tasks
- Limited customization vs building from scratch
- Pricing can add up with usage
Choose GPT-5.1 if you need:
General assistant, math problems, quick coding help
Choose CustomGPT if you need:
Business chatbots, customer service, knowledge bases
Ready to get started?
Both tools offer free tiers or trials. Try them out and see which one works best for your workflow.