If you have used custom GPTs in ChatGPT, you might wonder how Claude skills compare — and whether you need both. The two solve the same problem, turning a general AI into a specialist, but they go about it differently. This guide breaks down Claude skills vs custom GPTs on portability, setup, and cost, so you can decide which fits how you actually work. The honest answer for most people is that the difference matters less than it sounds, because a good skill file works in both.
The key distinction: a custom GPT lives inside ChatGPT, while a Claude skill is a portable file you can use anywhere. That single difference drives most of the trade-offs below.
What each one is
A custom GPT is a version of ChatGPT you configure with instructions, knowledge, and sometimes actions, saved inside your ChatGPT account. A Claude skill is an instruction file — usually a .md file — that you load into Claude Projects or paste as a system prompt. The GPT is a hosted setup; the skill is a portable document. Both make the model behave like a specialist; only one travels with you.
Portability
This is the biggest difference. A custom GPT only runs in ChatGPT, so if you switch tools or want to use the same specialist in Claude, you start over. A Claude skill is a file, so the same configuration works in Claude, ChatGPT, or any AI chat that accepts custom instructions. If you use more than one model, or expect to switch, the portable file wins clearly.
Setup and sharing
Custom GPTs are quick to set up inside ChatGPT and easy to share with a link, but that link only works for other ChatGPT users. A skill file is shared like any document — sent, stored, version-controlled — and used by anyone regardless of which AI tool they prefer. For a team that is not all on the same platform, the file is simpler to distribute.
Cost and ownership
Custom GPTs are tied to a ChatGPT subscription; when the subscription stops, access to the hosted GPT goes with it. A purchased skill file is yours to keep — a one-time download with no recurring fee, usable for as long as you have any AI chat to load it into. You own the file rather than renting access to a setup.
When a custom GPT makes sense
If you live entirely inside ChatGPT, never touch another model, and want built-in actions or hosted knowledge, a custom GPT is convenient. There is nothing wrong with that setup — it is the fastest route when you are committed to one platform.
When a Claude skill makes sense
If you use Claude, or use more than one model, or want to own the configuration outright and share it freely, a skill file is the better fit. It is portable, permanent, and platform-neutral. And because it is just a file, buying a tested skill is faster than writing a GPT from scratch. For how the catalogue is organised by role, see our guide to the Claude skills marketplace.
The verdict
If you are all-in on ChatGPT and never plan to leave, a custom GPT is fine. For everyone else — anyone using Claude, anyone using multiple models, anyone who wants to own and share the configuration — a Claude skill is the more flexible choice. And since the file works in ChatGPT too, choosing a skill does not lock you out of anything.
Own the file, use it in Claude, ChatGPT, or any AI chat. Tested skills by role, one-time download, no subscription.
Browse all skills →Read the marketplace guide →