Frequently asked questions
Quick answers about how CalculStore works, what happens to your numbers, and how far to rely on a result.
Using the calculators
Are the calculators really free?
Yes. Every calculator is free to use and you don't need an account. Ads help keep it that way.
How do I find a calculator quickly?
Use the search box, or press Ctrl K (Command K on a Mac) or the / key on any page. You can also type a sum such as 15% of 240 straight into search and get the answer right away.
Can I use CalculStore on my phone?
Yes. It works in the browser on phones, tablets and computers, with nothing to install.
Can I keep the calculators I use most?
Yes. Choose Save on any calculator and it appears at the top of the list on the home page, on that device.
Can I download a result?
Yes. You can download a result as a PDF or Excel report and add your own logo to it.
Does changing the currency convert my numbers?
No. It changes the symbol that's shown. Nothing is converted, because no exchange rates are fetched.
Which currencies can I choose?
US dollars, British pounds, euros, Canadian dollars, Australian dollars, Indian rupees and Japanese yen.
Is there a dark mode?
Yes. Use the button at the top of any page. Until you choose, the site follows your device's setting.
Privacy
Is what I type kept private?
Yes. Calculations run in your browser and nothing you type into a calculator is sent anywhere.
Are my entries saved?
Not unless you ask. Remember is off by default. If you turn it on, your entries stay in that browser until you turn it off, which deletes them.
Do you use cookies?
Google Analytics only runs if you accept it, and it never sees what you type into a calculator. Ads may use cookies too. Our privacy policy explains the details and your choices.
Is the password generator safe to use?
Passwords are made on your device with your browser's secure random source, and they are never sent to our server. Keep them in a password manager rather than a file or note.
Accuracy
How do the calculators work?
Each calculator page explains the method it uses, shows a worked example where one helps, and tells the story behind the formula, so you can check the working yourself.
Can I rely on the results for financial or medical decisions?
Results are estimates based on what you enter, not financial or medical advice. Please speak to a qualified professional before making an important decision.
What if I find a mistake?
Please tell us which calculator and which numbers you used, and we'll look into it.
About CalculStore
Who runs CalculStore?
CalculStore was founded by Prof. Alexandre Laurent, a mathematics educator with 15 years of teaching experience. You can read his story on our About page.
Why are there ads?
Ads help pay for the site so the calculators can stay free. They're always labelled, and they never sit inside a calculator's inputs or results.
Can you add a calculator I need?
Please suggest it. We'd like to know what would be useful.