eCommerce Fee Calculator Pro By 3Dsellers is a custom GPT that 3Dsellers publishes on ChatGPT. It answers eBay selling-fee and profit-margin questions in conversation: describe a sale in plain language and it works the fees through with you. It runs inside ChatGPT and nowhere else, so you need a ChatGPT account and must be signed in to open it - the GPT link opened while signed out shows a ChatGPT error instead. Access to custom GPTs is set by OpenAI and your ChatGPT plan, not by 3Dsellers.
⚠️ Treat what this GPT tells you as a starting point, not as a quote. Its answers are generated fresh in each conversation, with no 3Dsellers fee table behind them. Before you price an item on one of its numbers, confirm it with the 3Dsellers eBay Fee Calculator or eBay's own fee pages.
In this article:
What is eCommerce Fee Calculator Pro By 3Dsellers?
eCommerce Fee Calculator Pro By 3Dsellers is a custom GPT in the ChatGPT GPT store, filed under Productivity. There is no form and no calculator screen: you type your question into the chat box, or click one of four example prompts it offers. It has been available since June 2025 and was last updated on 1 September 2026, and its ChatGPT listing reports over 300 conversations and five reviews averaging 5.0. Although the name says eCommerce, its description names no marketplace other than eBay.
⭐ The "Pro" in eCommerce Fee Calculator Pro By 3Dsellers is not a paid 3Dsellers tier - no 3Dsellers plan is involved - and the GPT cannot see your listings, orders or settings.
What do I need, and what should I ask it?
A signed-in ChatGPT account, and nothing else: no 3Dsellers sign-up, no eBay connection, no install.
Sign in to ChatGPT and open eCommerce Fee Calculator Pro By 3Dsellers.
Ask your question, or click one of the four example prompts - they cover earnings after fees, free shipping, break-even price and the minimum price that avoids a loss.
Give it your selling price, item cost, shipping cost and buyer shipping charge - and name the eBay site and category, because eBay's fee depends on both.
Can I trust the numbers it gives me?
Enough to sanity-check a decision; not enough to set a price on. eCommerce Fee Calculator Pro By 3Dsellers has no fee table of its own: no knowledge files are attached to it and it has no custom action that could call 3Dsellers. The two tools it does have are web browsing and ChatGPT's own calculation tool, so each answer is worked out fresh - from whatever it reads at the time - rather than from a rate card 3Dsellers keeps current. Two runs of the same question can therefore give different numbers, and 3Dsellers cannot check a figure against a fee table it maintains. The ChatGPT description says the GPT "Always uses the most up-to-date information"; with no fee table behind it, that describes how it tries to answer, not a guarantee.
Which 3Dsellers fee calculator should I use?
3Dsellers has three ways to work out eBay fees, and they are not interchangeable. To set a price, use the 3Dsellers eBay Fee Calculator: free, no account, and every fee line shown.
Tool | What you need | Best at | A number you can price on? |
eCommerce Fee Calculator Pro By 3Dsellers (ChatGPT GPT) | A ChatGPT account, signed in | Fee and margin questions in plain language, and follow-ups no form has a field for | No - worked out per conversation, with no 3Dsellers fee table behind it |
3Dsellers eBay Fee Calculator (web page) | Nothing - free, no account, any browser | A sale you are planning: an itemised breakdown from your category, store level, Top Rated status and ad rate, plus net profit and break-even | Yes - rates ship with the page, which states the date they came from eBay |
eBay Fee Calculator - Final Value Fees & Profit Margin (free Chrome extension) | Google Chrome with the extension installed. No account | A listing already live: on an eBay item page it reads the price, shipping, title, image and category off the page, and detects the category automatically | Yes - fee tables ship inside the extension and the popup prints the date they were captured |
FAQ
Do I need a 3Dsellers account to use eCommerce Fee Calculator Pro?
No - eCommerce Fee Calculator Pro By 3Dsellers needs no 3Dsellers account, no subscription and no eBay connection. The only account it requires is a ChatGPT one, because it runs inside ChatGPT.
Why does the GPT link show an error when I open it?
Because eCommerce Fee Calculator Pro By 3Dsellers is only reachable from a signed-in ChatGPT account. Opened while signed out, the link shows the ordinary ChatGPT sign-in page with the banner "This GPT is inaccessible or not found" - which is a sign-in problem, not a deleted GPT. Sign in to ChatGPT, then open the link again.
Are the fee rates it quotes current?
You cannot tell from the answer alone, because no fee table is attached to the GPT. Check any rate it quotes against the 3Dsellers eBay Fee Calculator, which prints the date its rates came from eBay.
Can it look up one of my eBay listings?
No - eCommerce Fee Calculator Pro By 3Dsellers cannot reach your eBay account or a particular listing, so you type the numbers in yourself. For a listing that is already live, use the free Chrome extension eBay Fee Calculator - Final Value Fees & Profit Margin instead: it reads the figures straight off the eBay item page.
Can it replace the 3Dsellers eBay Fee Calculator?
No - eCommerce Fee Calculator Pro By 3Dsellers is a companion to it, not a replacement. Use the GPT to think a pricing question through, then the eBay Fee Calculator for the figure you actually price on.