1. What the site offers
The site offers calculators for online sellers (margin, ad ROAS, VAT, import cost, duty and VAT, marketplace calculators and more) and guides, free and without an account. We may change or stop parts of the service without notice to improve the information.
2. What the results mean
- Calculator results and guides are estimates for reference, based on published fee tables and laws. They may differ from a marketplace’s actual payout, the tax you file, or the duty decided by Korea Customs.
- Fees and tax rates are as of the check date shown on each page and may change when marketplace policies or laws change. Before important decisions, check the seller center, National Tax Service and Korea Customs information, or ask a tax professional.
- Except in cases of intent or gross negligence, bymay is not liable for losses arising from the use of the results.
3. Ads and affiliate links
To run the site we may show ads (such as Google AdSense) and include affiliate links (such as Coupang Partners). Areas with affiliate links are labelled. Advertisers and sellers are responsible for their ads, products and transactions.
4. Paid products
Paid products made by bymay (for example the Seller Pro Excel workbook) are sold on external stores such as Kmong or Gumroad. Payment, refunds and downloads follow that store’s terms and refund policy. You may use and edit a purchased file freely within your own business, but you may not share it with others or resell it.
5. Copyright
bymay holds the copyright in the site’s text, images, explanations of calculation methods and design. Quoting parts with credit (bymay and a link) or embedding a calculator in your blog with the embed feature is welcome. Please contact us before copying whole articles or redistributing them commercially.
6. Prohibited use
- Sending excessive automated requests that disrupt the site
- Clicking ads fraudulently or encouraging others to click them
- Distributing the site’s content as if it were not bymay’s
7. Changes and contact
When we change these terms, we post the changes and the effective date on this page. Contact us at adminsoohyeong@bymay.co.kr. These terms are governed by the laws of the Republic of Korea, and disputes are settled by the competent court under the Korean Civil Procedure Act.
8. Effective date
These terms apply from October 9, 2026.