Web Calculator & Highlighter

Turns any webpage into a calculator: click numbers to sum, average & more. Highlight, draw & annotate pages. Syncs across tabs.

Turn any webpage into a calculator, spreadsheet helper, and markup tool — without ever copying and pasting. Calculator & Highlighter lets you click any number on any webpage — prices, table cells, financial reports, invoices, stock tickers, spreadsheet-style data — and instantly get the sum, average, and more. Click and drag to highlight, draw, or annotate directly on top of any page. And unlike a basic calculator, your running total can follow you across pages and even across multiple open tabs. 🧮 INSTANT ON-PAGE CALCULATOR - Click any number to select it — get an instant Sum, Average, Min, Max, Median, and Mode - Three selection modes: Freehand (click any numbers), Row select, and Column select — built for tables - Custom Formula Builder: type your own expression (e.g. (10+20)*0.5) and insert your selected numbers with one click - Understands currency symbols ($, €, £, ₹, ¢), thousands separators, percentages, negative numbers in parentheses (accounting format), and magnitude shorthand like 1.2M or 2.5B - Works on data tables, financial dashboards, e-commerce listings, invoices, reports, and dynamically-loading or infinite-scroll tables 🔁 CARRY YOUR TOTAL ACROSS PAGES & TABS - Numbers you select keep adding to a running total as you browse to new pages — no starting over - Page History shows exactly which numbers came from which page, with one click to drop any page you don't want counted - Stay open in several tabs at once and they all share the same running total, synced live - A simple checkbox lets you include or exclude other pages from your total whenever you want 📋 EXPORT & COPY INSTANTLY - Copy Vertical (one per line — pastes as a column), Horizontal (tab-separated row), CSV, or just the Total - Quick Ctrl+C / Cmd+C, or right-click anywhere for the same options in the context menu - Paste-ready for Excel, Google Sheets, Notion, or any document ✏️ DRAW, HIGHLIGHT & ANNOTATE ANY WEBPAGE - Freehand pen drawing, plus rectangle and arrow shapes, directly over any page - Rich text annotations with bold, italic, underline, custom colors, font sizes, and emoji - Move, resize, and edit annotations anytime; undo/redo; clear everything in one click 🌓 BUILT FOR HOW YOU ACTUALLY BROWSE - Dark mode for day/night use - Draggable, resizable, minimizable panel that gets out of your way - Full keyboard shortcuts: Alt+X to open/close, Alt+R to reset, Alt+P for pen mode, R/C/F to switch selection modes, M for Custom Formula, Ctrl+Shift+C to clear drawings - Built-in help guide and contextual tips, so there's almost nothing to learn 💡 HOW IT WORKS 1. Click the toolbar icon (or press Alt+X) to open the calculator on any page 2. Click any number to select it and see instant stats 3. Switch to Row (R) or Column (C) mode for tables, or stay in Freehand 4. Use Custom Formula for your own equations, or Copy/Export your results 5. Switch to Draw mode to highlight, annotate, or sketch directly on the page Built for analysts double-checking a report, shoppers comparing prices, students and researchers doing quick math while reading, anyone reconciling numbers in a table, and anyone who wants to mark up or explain a webpage without a screenshot tool. If you've ever copied a column of numbers into a calculator app just to add them up, this replaces that entirely. 🔒 PRIVACY Everything runs locally in your browser. Calculator & Highlighter never sends your data anywhere — no analytics, no tracking, no external servers. Selected numbers and preferences are stored using Chrome's own local/session storage, on your device only, and your cross-page session clears itself once you close the tabs using it or close the browser. We don't collect personal data, browsing history, or page content.