Contact us
Every message goes straight to the people who build and maintain this site. There's no support queue and no bot — you're emailing whoever can actually fix it.
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| Operated by | 4C Tool Hub |
|---|---|
| Location | Ontario, Canada |
| Typical response | 1–2 business days |
| Languages | English |
What to include
A little detail turns a message we can't act on into one we can fix the same day:
- For a bug: which tool, what you entered, what happened, what you expected — plus your device and browser. "The invoice total didn't update on my iPhone in Safari after I changed the quantity" is immediately actionable.
- For a correction: the page, the figure you think is wrong, and what you believe it should be. We recalculate and, if you're right, fix it and update the page's revision date.
- For a suggestion: what you're actually trying to accomplish, rather than the feature you have in mind. Knowing the underlying task often produces a better tool than the one originally requested.
What we can't help with
To save you time: we can't give personal financial, tax, legal or medical advice, we can't tell you which lender, card or investment to choose, and we can't interpret your specific mortgage or loan agreement. Those need a qualified professional who can see your full situation. What we're glad to explain is how a calculation on this site works and why it produces the result it does.
Common questions
Do I need an account to use the tools?
No. Every tool is free and works without any sign-up or login. We don't have user accounts at all.
Are my files uploaded when I use the PDF or image tools?
No. Those tools run entirely in your browser using local processing — your files never leave your device. You can verify this by loading the page, disconnecting from the internet, and using the tool.
Can I use your calculators for my business or classroom?
Yes. Link to any tool freely — they're free for personal, educational and commercial use. If you're teaching from them, the guides may be more useful than the calculators alone.
Will you accept a guest post or paid link?
No. We don't publish guest content, sponsored posts or paid links of any kind. Please don't send those enquiries — they won't get a reply.
How is the site funded?
Advertising through Google AdSense, and nothing else. No affiliate links, no sponsored recommendations. See About for why that matters when reading our guides.