Contact
Ddukddak is built and run by one person. If a calculation looks wrong, a screen is broken, or there is a tool you wish existed, please say so.
Last updated · 6 September 2026
Write to the address below and you will get a reply once it has been read. It is a one-person site, so that can take a few days.
shinysky73@gmail.com
Reporting a bug
Including the following makes a fix much faster. For a wrong calculation in particular, the values you entered are what make it reproducible.
- Which tool it was, or the address of the page
- What you entered, what the screen showed, and what you expected instead
- The browser and device you used (for example, Safari on iPhone, Chrome on Windows)
- The exact wording of any error message
Suggesting a tool
If there is a repetitive job you do often and no good tool for it, let us know. Tools that can run entirely in the browser come first — it is better for you when what you type never leaves your machine.
Privacy enquiries
Questions about the privacy policy, or requests to delete the abuse-prevention request records, go to the same address. What is handled and what is not is set out in the privacy policy.