Help Center

Using a Calculator

Open any calculator, type your numbers into the fields, and the results update right away. There's no submit-and-wait and no account to create.

Each calculator gives you every related result at once. A circle calculator returns area, circumference, and diameter together; a loan calculator shows the monthly payment, total interest, and full schedule in one place. Enter your numbers once and get everything back.

Your most recent inputs are saved in your browser, so the numbers are waiting for you the next time you open that calculator. Nothing you type is sent to a server.

Install CalcTray as an App

You can add CalcTray to your home screen or desktop and launch it like any other app, with no app store and no download. It opens in its own window, without browser tabs or an address bar in the way, so your calculators are one tap away.

• Chrome (desktop or Android): click the install icon at the right of the address bar, or open the menu and choose Install. Chrome's guide.
• Microsoft Edge (desktop): open the menu, then Apps, then Install this site as an app. Edge's guide.
• Safari (iPhone or iPad): tap Share, then Add to Home Screen. Apple's guide.

Installing changes nothing about how CalcTray works: every calculation still runs privately in your browser, and none of your inputs leave your device.

Pick Up Where You Left Off

The home page keeps a short list of the calculators you've opened recently, so you can jump straight back to the tools you use most. The list is stored only on your device and is never uploaded. Select Clear history above the list to empty it whenever you want.

See Your Recent Results

Every calculation is saved to a private history on your device. On a calculator page, you'll see your last few results for that tool, so you can compare a couple of scenarios without retyping. The home page gathers your latest results from across every calculator in one place.

Each calculator has a Clear button above its history that wipes that calculator's saved results. Clearing a calculator also drops its entries from the home page list. Everything stays in your browser and never leaves your device.

Search for a Calculator

Use the search box to find a calculator by name. Start typing and matching calculators appear as you go. Pick one to jump straight to it. It's the fastest way to reach a specific tool without browsing by category.

The dropdown shows a handful of top matches. Press Enter instead of picking one to open the full search results page, which lists every calculator that matches your text.

Browse by Category

If you'd rather explore than search, calculators are grouped into categories: financial, math, health, everyday, science, and unit converters. Open any category from the footer to see the tools it holds. The All Calculators page lists every calculator on the site in one place.

Related Calculators

Near the bottom of each calculator you'll find Related Calculators, a short set of tools that pair well with the one you're using. They point you toward the next useful step without a trip back to search.

These aren't random. Most are drawn from the same category and picked for how much subject matter they share with the current tool, so the closest matches show first. A few calculators also have hand-picked links to related tools in other categories where that connection is more useful than a same-category match.

Share Your Results

Once you've run a calculation, a share bar appears. Copy link gives you a link that reopens the calculator with your numbers already filled in, so whoever you send it to sees exactly what you saw.

The same bar has buttons for the most common places people share: email, Slack, X, Facebook, LinkedIn, Reddit, and WhatsApp. On a phone, a Share button also opens your device's built-in menu so you can send the link to any other app.

Embed a Calculator on Your Site

Want a CalcTray calculator on your own site or blog? Each calculator has an embed option that gives you a short block of HTML. Copy it and paste it into your page wherever you want the calculator to appear. It runs right there for your visitors, with no account or setup required.

There's also an optional auto-resize setting. It adds a small script that keeps the embedded calculator's height matched to its content, so you won't see scrollbars or empty space after a result appears.

Switch Between Light and Dark

Use the light and dark toggle in the header to pick the look that's easiest on your eyes. CalcTray remembers your choice on your device, so it's the same the next time you visit.