Last updated: September 2026
The short version
The calculators on CentSum run entirely in your web browser. The numbers you type into a calculator are not sent to our servers and we do not store them. We do not ask you to create an account.
Information we collect
- Calculator inputs. Processed on your device only. We never receive them.
- Server logs. Our hosting provider may automatically record technical data such as IP address, browser type and pages requested, for security and to keep the service running.
- Email you send us. If you contact us we keep your message and address only to respond and improve the site.
- Preferences. Your light or dark theme choice is saved in your browser's local storage. It never leaves your device.
- Checklist progress. If you tick steps on one of our checklists, which steps you ticked is saved in your browser's local storage on your device so it is still there when you come back. It is not sent to us, it is not linked to you, and we cannot see it. You can erase it with the "Clear progress" button on the checklist or by clearing your browser's site data. It does not move to other devices or browsers.
- Saved scenarios. If you press "Save scenario" on a calculator, the name you give it and the numbers and results on screen are saved in your browser's local storage on your device. They are not sent to us, they are not linked to you, and we cannot see them. You can delete one from the list on the calculator, delete them all on the My saved scenarios page, or clear your browser's site data. They do not move to other devices or browsers.
- Notes. If you use "Add a note" under a heading on a guide, under a step on a checklist, or on a calculator page, the note you type and the name of that heading or step are saved in your browser's local storage on your device. They are not sent to us, they are not linked to you, and we cannot see them. You can delete a note with its "Delete note" button or clear your browser's site data. They do not move to other devices or browsers. A note is added to a printout only when you print on the same device.
- Calendar reminders. If you press "Download calendar reminders" or "Add due dates to my calendar", the file is built in your browser from the dates on screen and saved to your device by your browser. Nothing is uploaded. What you do with the file afterwards, such as importing it into a calendar app, is between you and that app.
- Printing. "Print or save this guide" and the print buttons on calculators and checklists hand the page to your browser's print dialog. On the California and Texas guides, "Print or save my plan" builds the plan in your browser from the answers on screen. Nothing is uploaded.
- Links to your numbers. If you press "Copy link to my numbers" on a calculator, or "Copy link to my answers" on a state guide, the link is built in your browser and copied to your clipboard. It contains the numbers you changed, so anyone you give the link to will see them. When someone opens such a link, their browser asks our web host for the page and the web address, numbers included, is part of that request. We use it only to fill in the calculator on their screen, but like any web address it can appear in the ordinary logs kept by our hosting provider. The site never puts your numbers in the address on its own. That only happens when you press the button.
We do not currently use analytics tools. If that changes we will update this page.
Advertising and cookies
We may show ads through Google AdSense. Google and its partners are third-party vendors that use cookies and similar technologies to serve ads based on your visits to this and other websites.
- Google's use of advertising cookies enables it and its partners to serve ads to you based on your visit to our site and other sites on the internet.
- You can opt out of personalized advertising by visiting Google Ads Settings.
- You can also opt out of some third-party vendors' use of cookies for personalized advertising at aboutads.info.
- To learn more about how Google uses information from sites that use its services, see How Google uses information from sites or apps that use our services.
When advertising is active, visitors in the European Economic Area, the United Kingdom and some US states will see a consent or opt-out message provided by Google's certified consent tool, so you can control how ad cookies are used.
Links to other sites
Our pages link to sources such as the IRS. We do not control those sites and are not responsible for their privacy practices.
Children
CentSum is a general-audience website and is not directed to children under 13. We do not knowingly collect personal information from children.
Your rights
Depending on where you live, you may have rights to access, correct or delete personal information, or to object to certain processing. Because we hold very little personal information, most requests are simple to fulfil. Email hello@centsum.com and we will respond.
Changes to this policy
We may update this policy from time to time. The date at the top shows when it was last revised.