GPT-5.2 o1 vs CustomGPT
A comprehensive 2026 comparison to help you choose the right AI tool for your needs. We tested both extensively.
Quick Verdict: GPT-5.2 o1 vs CustomGPT
After extensive testing, **GPT-5.2 Thinking** comes out ahead with a 4.9/5 rating. It's the better choice for most users, especially those focused on Complex reasoning, software engineering, research, math proofs. However, CustomGPT remains competitive and may be preferable if you prioritize Business chatbots, customer service, knowledge bases.
GPT-5.2 Thinking edges out CustomGPT with superior overall performance and features that make it the better choice for most users in 2026. With a 4.9/5 rating, it excels particularly in Complex reasoning, software engineering, research, math proofs.
Try GPT-5.2 o1 FreeFeature Comparison Table
Side-by-side comparison of key features and capabilities
When to Use GPT-5.2 o1 vs CustomGPT
Choose GPT-5.2 o1 When You Need:
- Complex reasoning, software engineering, research, math proofs
- Superior coding assistance and code generation
- Better quality content writing and creative tasks
- Processing longer documents with 128K context
Choose CustomGPT When You Need:
- Business chatbots, customer service, knowledge bases
- Faster response times for time-sensitive work
- Testing capabilities with a free tier before committing
In-Depth Analysis: GPT-5.2 o1 vs CustomGPT
Performance & Capabilities
In our comprehensive testing for 2026, we evaluated both GPT-5.2 Thinking and CustomGPT across multiple dimensions including coding tasks, creative writing, reasoning problems, and general conversation quality. GPT-5.2 Thinking emerged as our top pick with an overall rating of 4.9/5.
GPT-5.2 Thinking scored 4.8/5 on coding tasks, making it an excellent choice for developers. In comparison, CustomGPT also performs well in this category.
Pricing & Value
When it comes to pricing, CustomGPT offers a free tier for testing. For paid plans, CustomGPT is more affordable at $49/month compared to $200/month.
Use Cases & Target Audience
GPT-5.2 Thinking is particularly well-suited for Complex reasoning, software engineering, research, math proofs. Its strengths make it ideal for professionals who need advanced coding help, quality content creation, and reliable AI assistance.
CustomGPT, on the other hand, excels at Business chatbots, customer service, knowledge bases. Users who prioritize fast response times, complex reasoning, will find it particularly valuable.
GPT-5.2 Thinking Pros & Cons
Pros
- Best reasoning model from OpenAI
- Edges out Gemini 3 and Claude Opus 4.5 on most tests
- Performs at/above human expert level on GDPval
- Excellent for coding, math, and document analysis
- State-of-the-art on SWE-Bench Pro
Cons
- Expensive ($200/mo for Pro subscription)
- Slower than Instant variant
- Requires Pro subscription for full access
- Writing can feel robotic
CustomGPT Pros & Cons
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
Best For: GPT-5.2 o1
Complex reasoning, software engineering, research, math proofs
Best For: CustomGPT
Business chatbots, customer service, knowledge bases
Frequently Asked Questions
Common questions about GPT-5.2 o1 vs CustomGPT
Is GPT-5.2 Thinking better than CustomGPT in 2026?
Based on our benchmarks and analysis, GPT-5.2 Thinking performs better overall with a rating of 4.9/5. However, the best choice depends on your specific needs - GPT-5.2 Thinking excels at Complex reasoning, software engineering, research, math proofs, while CustomGPT is better for Business chatbots, customer service, knowledge bases.
What is the price difference between GPT-5.2 o1 and CustomGPT?
GPT-5.2 Thinking costs $200/month for paid plans. CustomGPT offers a free tier and costs $49/month for paid plans.
Which is better for coding: GPT-5.2 o1 or CustomGPT?
Both tools can assist with coding tasks. Check our detailed comparison above to see benchmark results.
Can I use GPT-5.2 o1 and CustomGPT for free?
GPT-5.2 Thinking requires a paid subscription. CustomGPT does offer a free tier with limited features. Both tools offer trial periods or limited free access for new users.
Which AI has a larger context window: GPT-5.2 o1 or CustomGPT?
GPT-5.2 Thinking has a larger context window at 128,000 tokens, compared to 100,000 tokens. Larger context windows allow processing more text in a single conversation.
Is GPT-5.2 o1 faster than CustomGPT?
In our speed tests, CustomGPT is faster with a speed rating of 4.5/5. Response times can vary based on server load and query complexity.
Which is better for writing content: GPT-5.2 o1 or CustomGPT?
For content writing, GPT-5.2 Thinking excels with a writing rating of 4.5/5 versus 4.0/5. Consider your specific writing needs when choosing.
Do GPT-5.2 o1 and CustomGPT support image generation?
GPT-5.2 Thinking supports image understanding and analysis. CustomGPT does not have built-in image capabilities. For dedicated image generation, consider specialized tools like DALL-E or Midjourney.
Which AI should beginners choose: GPT-5.2 o1 or CustomGPT?
For beginners, we recommend CustomGPT since it offers a free tier. GPT-5.2 Thinking has a slightly better overall user experience based on our testing.
Can I switch from GPT-5.2 o1 to CustomGPT easily?
Yes, switching between AI tools is straightforward since they use similar prompting interfaces. Your conversation history won't transfer, but you can export important outputs. Many professionals use both tools depending on the task - GPT-5.2 Thinking for Complex reasoning, software engineering, research, math proofs and CustomGPT for Business chatbots, customer service, knowledge bases.
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Ready to Get Started?
Both tools offer free tiers or trials. Try them out and see which one works best for your workflow in 2026.