Print Size Calculator

WHAT IT DOES

Print Size Calculator is a floating panel that helps photographers, designers, and printers determine the optimal print dimensions for digital images. Enter your image's pixel dimensions (width and height), a target print width or height (in inches or centimeters), and a DPI (dots per inch) value—the panel instantly calculates the corresponding print size, the required pixel dimensions for a target print size, and the effective DPI needed to print at a given size. The panel includes a unit toggle to switch between inches and centimeters, and displays the image's aspect ratio along with a fit analysis that tells you whether the image will be cropped or letterboxed to fit the target dimensions. You can insert the calculated print dimensions or effective DPI directly into any editable field on the page (input, textarea, or contenteditable) with one click, or copy all results to your clipboard. Perfect for print prep, photo enlargement, canvas sizing, or any project where digital pixels meet physical paper.

WHERE IT RUNS

The panel overlays any website that loads the BotGentz extension—whether you're on a photo editor, a print shop order page, a design tool, a spreadsheet, or any other web page. It works on all modern Chromium‑based browsers (Chrome, Edge, Brave, Arc) and Firefox. The script injects a self‑contained UI element that does not interfere with the host page's layout, styles, or JavaScript execution. It runs client‑side only, with no external API calls or cloud dependencies.

HOW TO USE

After installing the free BotGentz extension, visit any page and click the extension icon to activate the panel. The first time you use Print Size Calculator, it will appear as a draggable widget near the bottom‑right corner of your viewport. To calculate print dimensions:

- Enter the image's pixel width and height in the "Width (px)" and "Height (px)" fields.

- Toggle "Use cm instead of inches" if you prefer metric units.

- Enter either a target print width or height (or both) in the print dimension fields.

- Enter a DPI value (default 300 DPI, standard for high‑quality prints).

The panel updates all calculations live—print size, required pixel dimensions, effective DPI, aspect ratio, and fit analysis (cropped, letterboxed, or perfect fit). To use the results:

- Click "Insert Print Size" to paste the calculated dimensions (e.g., "10.00 × 6.67 in") into the focused editable field.

- Click "Insert Effective DPI" to paste the effective DPI value into the focused field.

- Click "Copy All Results" to copy the print size, required pixels, effective DPI, aspect ratio, and fit analysis to your clipboard.

The panel remembers your last used DPI value and unit preference across sessions.

ASPECT‑RATIO‑AWARE DIMENSIONAL ENGINE WITH FIT DETECTION

Unlike simple pixel‑to‑inch converters that treat width and height independently, this panel uses an aspect‑ratio‑aware engine that preserves the image's proportional integrity. The engine calculates the image's aspect ratio (width divided by height) and uses it as a constraint for all dimensional computations. When only one print dimension is provided, the engine derives the other dimension by multiplying or dividing by the aspect ratio, ensuring the image never stretches or distorts. When both dimensions are provided, the engine compares the DPI‑derived dimensions with the target dimensions to determine the fit: if the aspect ratios match, it reports a perfect fit; if the target is wider (lower aspect ratio), it letterboxes horizontally; if the target is taller (higher aspect ratio), it letterboxes vertically. The engine also computes the effective DPI as the lower of the two DPI values derived from width and height, which represents the maximum printable quality without upscaling. All calculations use floating‑point precision with rounding to two decimal places for dimensions and one decimal for DPI, providing professional‑grade accuracy for print production.

THE PANEL

- Drag: Click and hold the panel's header bar to move it anywhere on the screen.

- Per‑site position: The panel stores its last position separately for each domain (e.g., different positions for Photoshop Express vs. Printful) using the browser's localStorage, keyed by hostname.

- Snap: When dragged near any edge of the viewport, the panel snaps to that edge with a 16px margin for a clean, docked feel.

- Collapse: Click the "−" button in the header to collapse the panel to a compact title bar, preserving all current values. Click "+" to expand it back.

- Resize: Drag the bottom‑right corner handle to resize the panel from 280px to 600px wide and 200px to 500px tall; the layout adapts responsively.

- Escape: Press the Escape key while the panel is focused to close it entirely (you can reopen it from the extension toolbar).

PLEASE NOTE

This script requires the free BotGentz extension to run—it is not a standalone bookmarklet or user script. Websites frequently update their DOM structures and security policies; while we strive to keep the panel functional across thousands of sites, occasional updates may be needed. The calculator performs all operations entirely in your browser—no data is sent to any server, and no cookies or tracking identifiers are used. Your image dimensions, print settings, and DPI values remain private to your local session and are persisted only via GM_setValue (the extension's local storage) for convenience, not shared across devices or sessions. Print quality depends on the printer's native resolution and paper type; the effective DPI calculation is a guideline. Always verify with test prints for critical projects.