Privacy Policy

• The numbers you type into a calculator are worked out in your browser. They are not sent to us.
• You do not need an account, and we do not ask for your name, email address or any financial details.
• We store two small items in your browser: your light or dark theme and your cookie choice.
• Optional analytics and advertising cookies are off unless you accept them (see our Cookie Policy).
• We do not sell your information.

SumLark is a free website of UK money and household calculators. In this policy, “we”, “us” and “SumLark” mean the people who run sumlark.com. You can contact us about this policy or your information at hello@sumlark.com.

The numbers and choices you enter (for example a salary, a region or the hours an appliance runs) are used only in your browser to work out the result. They are not sent to our servers and we do not see them.

The inputs are shown in the web address of the page so that you can bookmark or share a result. If you use “Copy link” and send the link to someone, they will be able to see the numbers in it. Treat the link like anything else you share.

Our website is delivered by Cloudflare. When you visit, Cloudflare processes technical information such as your IP address, browser and device type, the pages you request and the date and time. This is needed to deliver the pages, keep the site secure and protect it from attacks and abuse. Read Cloudflare’s privacy policy for how they handle it.

Your browser stores your theme choice and your cookie choice on your own device, so that we can remember them. These are not used to identify you. See the Cookie Policy.

We do not use analytics or advertising cookies at the moment. We expect to add privacy-conscious analytics and advertising (such as Google AdSense) to help us improve the site and keep it free.

If we do, we will ask for your consent before any optional cookie is set, we will update this policy and the Cookie Policy to name each provider, and you will be able to change your mind at any time. Advertising providers may set cookies and receive information such as your IP address and the pages you view; their own privacy policies then apply.

If you write to hello@sumlark.com, we use your email address and what you tell us to reply to you and, if you report a mistake, to check and fix it. We keep the email for as long as we need to deal with it and for a reasonable time afterwards in case you write again. Then we delete it.

Under UK data protection law we need a lawful basis. We rely on:

• Legitimate interests to run, secure and improve the site and to reply to messages you send us. We think this is fair because the information is limited and the use is what you would expect.
• Consent for optional cookies and similar technologies. You can withdraw it at any time from the “Cookie settings” link in the footer.

We do not sell your information. We use a small number of providers who handle information on our behalf, such as our website host and our email service, and they may only use it to provide that service to us. We may also disclose information if the law requires it.

Some providers are based outside the UK. Where information is transferred, we choose providers that use recognised safeguards for international transfers.

Under UK data protection law you have the right to:

• be told how your information is used (this policy)
• ask for a copy of the information we hold about you
• ask us to correct information that is wrong
• ask us to delete your information
• ask us to restrict, or object to, how we use it
• ask for your information in a portable format
• withdraw consent at any time

Email hello@sumlark.com and we will reply within one month. Because we do not collect accounts or names, we may not hold information that can be linked to you; if so we will tell you.

If you are unhappy with how we have handled your information, you can complain to the Information Commissioner’s Office (ICO) at ico.org.uk/make-a-complaint. We would appreciate the chance to put things right first.

SumLark is meant for adults. We do not knowingly collect information from children.

We will update this page if what we do changes, for example when we add analytics or advertising. The date at the top shows when it was last changed.