Side Panel Calculator

A full-featured calculator that lives in your side panel. Side Panel Calculator uses Chrome's side panel (chrome.sidePanel) so a calculator is one click away on any page. No extra tab, no extra window — just do the math where you are and keep working. ■ Math that doesn't drift In many calculators 0.1 + 0.2 comes out as 0.30000000000000004, because computers store decimals in binary. This extension works in decimal internally and keeps every digit, so 0.1 + 0.2 is exactly 0.3, and 1 ÷ 3 × 3 comes back to 1. Tax and expense figures add up to the cent. ■ Four modes ・Simple: the four basic operations, nothing in the way ・Advanced: ±, percent, memory (M+/M-/MR/MC) and your own quick-calc buttons ・Scientific: sin/cos/tan, log, ln, √, powers, factorial, degrees/radians ・Programmer: binary, octal, decimal and hex side by side, AND/OR/XOR/NOT and shifts, 8/16/32/64-bit widths Switch instantly from the dropdown at the top. Keyboard input is supported throughout. ■ History, in every mode Every calculation is kept with its expression, and switching modes never clears it. ・Tap an entry to pick the result back up and keep calculating ・Delete entries one at a time with the trash icon — and undo right after ・Tick the rows you care about to total just those, which is all you need for a receipt or an expense claim ・Copy the whole history, or clear it in one go ■ Clearing you can trust "C" clears the last entry and "AC" clears everything — two separate buttons, so a slip never wipes the session. Double-click C to clear the whole calculation in progress. After an AC you get five seconds to undo it. You can also hide AC entirely and use a long press (0.6s) on C instead. ■ Quick-calc buttons Build up to six one-tap buttons for the arithmetic you repeat — "+10%" for tax, "-20%" for a discount, whatever you use. Set the label, the operation and the number yourself; they sit right above the keypad (in Advanced and Scientific mode). ■ Units and currency Convert length, weight, area, volume and data sizes, plus currency at live rates. ・Search for a unit or a currency: type and the matches appear right below the box, ready to click. Search by code, country or currency name ・The value field accepts an expression, so "120+120+120" works as an input ・Copy either side of the conversion with one tap ・Rates come from the Frankfurter API, which publishes the European Central Bank's official rates, and are cached on your device (the fetch time is shown; offline, the last known rates are used and labelled as such) ■ Make it yours Four themes: follow the system, light, dark, or custom. In custom you set the background, text, button colours, font size and corner radius, with a live preview in settings. ■ Four languages 日本語, English, 中文（简体）and 한국어. The extension follows your browser's language automatically, or you can pick one in settings. If a translation reads wrong, there is a link in settings to tell us. ■ Only the permissions it needs ・storage: to save your settings and history ・sidePanel: to show up in the side panel ・access to api.frankfurter.dev: to fetch exchange rates (nothing is requested unless you use currency conversion) No ads, no tracking, no personal data sent anywhere. Your calculations and history stay in your browser. Good for you if you ・want to calculate something without losing your place on the page ・work out tax or discounts while shopping or filing expenses ・convert currencies or units regularly ・are a student or engineer who needs scientific or programmer functions Keep it in your side panel and let the small calculations take care of themselves.