Custom GPTs vs Gemini Gems: I've Built Both — Here's My Honest Take (2026)

We have all tried different AI assistants like ChatGPT, Claude, and Gemini. These are generalist AI assistants that are intelligent and capable enough for the majority of people. These AI assistants can answer most, if not all, of your questions, and if you provide them with documents, they are highly likely to base the responses you receive on those documents. However, there are still multiple chances of hallucination, but still nothing too bad that a quick review can't fix.

However, both ChatGPT and Gemini allow you to do something more than just chat with them. You can build your very own custom version of ChatGPT called Custom GPTs and custom AI experts for help on any topic in Gemini called Gems. Both Custom GPTs and Gemini Gems serve the same purpose.

Custom GPTs vs Gemini Gems: My Honest Take

What is a Custom GPT?

A Custom GPT is a customized version of ChatGPT that you configure for one specific task. It could be a "Brand Voice Editor," a "Python Tutor," a "Contract Explainer." OpenAI launched them in late 2023, and they were the company's first real move to turn ChatGPT from a single chatbot into a platform. You build your own custom GPT inside ChatGPT under Explore GPTs → Create, with no coding required.

Here's what Custom GPTs are best known for:

• The two-path builder: You can describe what you want in a conversational GPT Builder that interviews you, or flip to the Configure tab and set everything by hand, name, instructions, conversation starters, and capabilities.
• Actions (the killer feature): You can wire a GPT to an external API using an OpenAPI schema, a structured description of how another service's API works, so your GPT can actually fetch live data or trigger workflows in other systems.
• Built-in capabilities: You toggle on web browsing, image generation, and the Code Interpreter, a sandbox that runs code to do real data analysis on files you upload.
• Flexible sharing: A GPT can stay private, be shared by link, shared in a workspace, or published to everyone.

Why you might prefer a Custom GPT over a Gem:

If you're a builder, developer, or creator who wants your assistant to do things in other tools, not just answer questions, Custom GPTs are in a different league. The tradeoff is that creating one requires a paid ChatGPT plan, and the sheer number of options can feel like more than a casual user needs.

What is a Gemini Gem?

A Gem is Google's version of the same idea, built into Gemini. Google previewed Gems at I/O in 2024. The philosophy is almost the opposite of OpenAI's: less of a marketplace, more of a personal toolbox that sits inside the Google apps you already use all day. You create one in the Gem manager at gemini.google.com.

Here's what Gems are best known for:

• Free for everyone: Since March 2025, Google has rolled Gems out to all users at no cost, for both use and creation, removing the single biggest barrier to entry.
• Dead-simple setup: You give the Gem a name and write instructions; Google even nudges you toward a good structure (role, task, context, format). That's the whole core flow.
• Knowledge files + Google Drive: You can attach up to 10 files per Gem, or link directly to Google Drive documents so the Gem references your actual material.
• Premade Gems to start from: Five ship out of the box: Brainstormer, Career Guide, Coding Partner, Learning Coach, and Writing Editor, so you can see how a well-built Gem behaves.

Why you might prefer a Gem over a Custom GPT:

If you use Gmail, Docs, and Drive and want something free and easy to access, Gems are a good choice. However, they have limitations; there is no system for integrating other tools, and you can't share what you create in a public store.

What's the main difference between Custom GPTs and Gemini Gems?

The cleanest way to think about it: Custom GPTs are built for builders, and Gemini Gems are built for users.

• The ideal Custom GPT user is someone who wants to connect their assistant to a real API, analyze data in a code sandbox, and maybe distribute their creation to an audience.
• The ideal Gem user isn't trying to build a product; they're trying to stop repeating themselves and get a personalized helper that knows their Drive.

How to Build a Custom GPT:

Step 1: Visit GPTs on ChatGPT. Click on Create to create a custom version of ChatGPT.

Step 2: Go to configure and add Name, Description, Instructions, Conversation starters, Knowledge, AI Model of choice, and Capabilities. Once all that is done, click on create. You can also test and preview your custom GPT before finalizing.

Step 3: Use your custom GPT for your everyday tasks.

How to Create a Gemini Gem:

Step 1: Visit the Gem manager in Gemini. Click on New Gem to create your own Gem.

Step 2: In the editor, add Name, Description, Instructions, Default tool, and Knowledge. Once all that is done, click on save. You can also test and preview your custom GPT before finalizing.

Step 3: Use your Gem for your everyday tasks.

Editor's note:

While both Custom GPTs and Gemini Gems are powerful features, I don't know why you would choose them over ChatGPT Projects, Claude Projects, and Gemini Notebooks. I do think if you need a custom version of ChatGPT, you can go with GPTs, or if you want to create your own custom AI assistant and expert, you can use Gems. However, personally, I'd choose Projects over custom GPTs and Gemini Gems.