Grammarly vs CustomGPT
A comprehensive 2026 comparison to help you choose the right AI tool for your needs. We tested both extensively.
Quick Verdict: Grammarly vs CustomGPT
After extensive testing, **Grammarly** comes out ahead with a 4.6/5 rating. It's the better choice for most users, especially those focused on Grammar checking, professional emails, academic writing. However, CustomGPT remains competitive and may be preferable if you prioritize Business chatbots, customer service, knowledge bases.
Grammarly edges out CustomGPT with superior overall performance and features that make it the better choice for most users in 2026. With a 4.6/5 rating, it excels particularly in Grammar checking, professional emails, academic writing.
Try Grammarly FreeFeature Comparison Table
Side-by-side comparison of key features and capabilities
When to Use Grammarly vs CustomGPT
Choose Grammarly When You Need:
- Grammar checking, professional emails, academic writing
- Better quality content writing and creative tasks
- Faster response times for time-sensitive work
- Testing capabilities with a free tier before committing
Choose CustomGPT When You Need:
- Business chatbots, customer service, knowledge bases
- Processing longer documents with 100K context
- Testing capabilities with a free tier before committing
In-Depth Analysis: Grammarly vs CustomGPT
Performance & Capabilities
In our comprehensive testing for 2026, we evaluated both Grammarly and CustomGPT across multiple dimensions including coding tasks, creative writing, reasoning problems, and general conversation quality. Grammarly emerged as our top pick with an overall rating of 4.6/5.
Grammarly handles coding tasks well, making it suitable for basic programming assistance. In comparison, CustomGPT also performs well in this category.
Pricing & Value
When it comes to pricing, both tools offer free tiers, making them accessible for testing. For paid plans, Grammarly is more affordable at $12/month compared to $49/month.
Use Cases & Target Audience
Grammarly is particularly well-suited for Grammar checking, professional emails, academic writing. Its strengths make it ideal for professionals who need 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.
Grammarly Pros & Cons
Pros
- Works everywhere (browser, desktop, mobile)
- Excellent grammar and spelling
- Tone detection
- Plagiarism checker
- GrammarlyGO AI assistant
Cons
- Not for creative writing
- Premium features require subscription
- Can be overly corrective
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: Grammarly
Grammar checking, professional emails, academic writing
Best For: CustomGPT
Business chatbots, customer service, knowledge bases
Frequently Asked Questions
Common questions about Grammarly vs CustomGPT
Is Grammarly better than CustomGPT in 2026?
Based on our benchmarks and analysis, Grammarly performs better overall with a rating of 4.6/5. However, the best choice depends on your specific needs - Grammarly excels at Grammar checking, professional emails, academic writing, while CustomGPT is better for Business chatbots, customer service, knowledge bases.
What is the price difference between Grammarly and CustomGPT?
Grammarly offers a free tier and costs $12/month for paid plans. CustomGPT offers a free tier and costs $49/month for paid plans.
Which is better for coding: Grammarly or CustomGPT?
Both tools can assist with coding tasks. Check our detailed comparison above to see benchmark results.
Can I use Grammarly and CustomGPT for free?
Grammarly does offer a free tier with limited features. 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: Grammarly or CustomGPT?
CustomGPT has a larger context window at 100,000 tokens, compared to 50,000 tokens. Larger context windows allow processing more text in a single conversation.
Is Grammarly faster than CustomGPT?
In our speed tests, Grammarly is faster with a speed rating of 5.0/5. Response times can vary based on server load and query complexity.
Which is better for writing content: Grammarly or CustomGPT?
For content writing, Grammarly excels with a writing rating of 4.8/5 versus 4.0/5. Consider your specific writing needs when choosing.
Do Grammarly and CustomGPT support image generation?
Grammarly does not have built-in image capabilities. 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: Grammarly or CustomGPT?
For beginners, we recommend starting with either - both offer free tiers to experiment. Grammarly has a slightly better overall user experience based on our testing.
Can I switch from Grammarly 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 - Grammarly for Grammar checking, professional emails, academic writing 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.