Custom GPTs vs Claude Projects: which one for your business?

Side-by-side

Feature	Custom GPTs	Claude Projects
Cost to create	ChatGPT Plus ($30 AUD/mo)	Claude Pro ($30 AUD/mo)
Cost to use	Free tier OK	Claude Pro only
Custom instructions	Yes	Yes
Knowledge files (RAG)	Yes (up to 20 files)	Yes (up to 20MB total)
API actions (call your tools)	Yes	No (you’d use MCP for Claude)
Share publicly	Yes, via GPT Store	No (private only)
Share with team	Yes, Team plan	Yes, Team plan
Voice mode	Yes	No
Image generation	Yes (DALL-E)	No
Browser-based	Yes	Yes
Mobile app support	Yes	Yes
Long-context window	128k tokens	1M tokens (Sonnet 4.6)

When to use which

Use a Custom GPT when:

• You want a public-facing AI tool (e.g. “Resume Reviewer GPT” you publish to the GPT Store)
• Your workflow requires Microsoft 365 / Google Drive integration via Actions
• You need DALL-E image generation as part of the workflow
• You want voice mode interactions
• You’re building for a non-technical audience (the share-link UX is friendlier)

Use a Claude Project when:

• You’re doing longer-form writing (blogs, briefs, contracts, long emails)
• You need a 1M-token context window (uploading whole codebases, full books, multi-quarter chat logs)
• You want the slightly higher-quality reasoning output for hard problems
• Your data is sensitive and you prefer Anthropic’s data-handling posture
• You’re a developer who’d rather wire integrations via MCP than via Custom GPT Actions

Real examples

Custom GPTs we use:

• Voice training GPT for our marketing team. Loaded with 20 past On Autopilot articles + the editorial style guide. Anyone on the team can use it to draft new pieces in the house voice.
• Audit-form-reply GPT. Loaded with our service descriptions, pricing, and 30 past good audit-form replies. Drafts personalised first-touch responses to new audit submissions.
• CV-screening GPT. Loaded with the brief for a specific role. Reviews CV submissions against the brief and flags top-5 candidates.

Claude Projects we use:

• Long-form article drafting. A Project with the editorial style guide + 20 past articles + a research brief loaded as persistent files. Used for the deep-dives.
• Code review. A Project for each of our larger codebases, with CLAUDE.md and architectural notes uploaded. Drafts code reviews, finds bugs, suggests refactors.
• Client-specific work. One Project per ongoing client (anonymised), with their brand voice + past deliverables loaded.

The pattern most owner-operators end up with

1. One Custom GPT for the public/shareable tool (e.g. an industry-specific assistant or lead-screening tool)
2. One Claude Project for your private/internal workflow (drafting, analysis, longer-context work)
3. Iterate on prompts based on what the outputs actually need

Total cost: $60 AUD/month for both subscriptions. Worth it within a week of daily use.

What about Gemini’s equivalent?

Gemini has “Gems” (their version of Custom GPTs) in 2026. Capable but less polished than either Custom GPTs or Projects. Best ignored unless you live in Google Workspace.

What about open-source / self-hosted equivalents?

You can build similar workflows using LangChain, LlamaIndex, or n8n with Ollama for model hosting. Higher learning curve, lower ongoing cost. Worth it for technical teams or strict data-residency requirements.

How to choose if you can only pick one

Go to your business’s biggest weekly pain point:

• Drafting customer replies? → Custom GPT (better integrations).
• Writing content / blog / longform? → Claude Project (better drafts).
• Both equally? → Custom GPT first because the Microsoft 365 + Google Drive integrations make it easier to wire into your existing tools.

Then experiment with the other one when you find a workflow the first doesn’t fit.

See also

• Claude vs ChatGPT for Australian small business for the broader tool comparison.
• How to write better AI prompts for the prompt patterns these tools are built around.
• AI for email for the specific inbox workflow.