What do offset-X and offset-Y mean in CSS box shadows?

Offset-X determines the horizontal position of the shadow (positive values shift right, negative values shift left). Offset-Y determines the vertical position (positive values push down, negative values push up), controlling simulated light source angles.

What is the difference between blur radius and spread radius?

Blur radius controls how soft and feathered the shadow edge appears (0px creates a hard shadow). Spread radius expands or contracts the physical dimensions of the shadow shape before blur is applied, expanding or shrinking its footprint.

How do I create an inner shadow (inset) using CSS?

To create an inner shadow that appears inside element borders (common for text inputs and pressed buttons), add the inset keyword to the beginning of your box-shadow CSS property (e.g., box-shadow: inset 0px 2px 4px rgba(0,0,0,0.1)).

How can I layer multiple box shadows on a single element?

CSS allows comma-separated shadow definitions on a single property (e.g., box-shadow: 0 1px 3px rgba(0,0,0,0.1), 0 10px 20px rgba(0,0,0,0.05)). Layering a sharp tight shadow with a soft wide shadow creates photorealistic material elevation.

Does using heavy box shadows affect website performance?

Extremely large blur radii or animating box-shadow during page scrolling can trigger GPU layer re-paints. For smooth 60fps animations, animate opacity or transform on pseudo-elements instead of directly animating large box-shadow blur values.

Why are RGBA colors used instead of HEX for box shadows?

RGBA allows precise control over alpha transparency (e.g., rgba(0, 0, 0, 0.15)). Using semi-transparent shadows ensures the shadow blends naturally over varying background colors and images without creating harsh black smudges.

Are my custom box shadow configurations stored on any server?

No. All shadow calculations and CSS rendering happen strictly within your local web browser session. ToolJiffy does not collect, log, or transmit any design properties or generated code snippets to remote servers.

Is this CSS box shadow generator completely free to use?

Yes! The ToolJiffy CSS Box Shadow Generator is 100% free with unlimited usage, zero account registration requirements, no subscription paywalls, and no watermarks for all personal and commercial web projects.

CSS Box Shadow Generator

Design box shadows visually with a live preview and copy production-ready CSS. Free, private, in-browser.

100% Private — Runs entirely in browserInstant calculation & resultFree, no sign-up

Offset X: 0Offset Y: 10Blur: 24Spread: 0ColorOpacity %: 25

CSS

box-shadow: 0px 10px 24px 0px rgba(25, 26, 35, 0.25);

Why use a visual CSS box shadow generator for UI design?

Box shadows are fundamental to web UI design, providing visual cues for depth, z-index elevation, and interactive hierarchy. In modern user interface design systems (such as Material Design, Tailwind UI, or Apple Human Interface Guidelines), cards float, dropdown menus hover, and modal dialogs cast soft drop shadows over background overlays. Crafting photorealistic shadows by hand requires fine-tuning multiple numeric parameters: horizontal offset, vertical offset, blur radius, spread distance, and semi-transparent RGBA color values. The ToolJiffy CSS Box Shadow Generator lets you adjust these parameters visually with instant live feedback.

Instead of manually tweaking pixel offsets and refreshing your browser in an endless edit cycle, this visual playground gives you immediate visual confirmation of depth and light source direction while generating standard CSS code.

Precise Multi-Parameter Controls: Fine-tune offset X, offset Y, blur radius, spread distance, shadow color, and alpha opacity with interactive sliders.
Real-Time Visual Elevation Preview: Watch element depth transform instantly in a live interactive box preview container before copying code.
Clean RGBA Output Syntax: Generates standard W3C box-shadow properties using readable rgba() color strings for predictable opacity blending.
Modern UI Elevation Design: Create modern soft ambient shadows, crisp card borders, inset inputs, and floating modal elevation levels effortless without guessing numbers.

CSS W3C box shadow rendering model

The generator models the W3C CSS Backgrounds and Borders Module Level 3 specification for the `box-shadow` property (`box-shadow: offset-x offset-y blur-radius spread-radius rgba(r, g, b, alpha)`). As controls move, the engine converts hexadecimal color selections into 8-bit RGB components, scales alpha percentages to decimal representations (0.0 to 1.0), and formats string outputs.

The resulting style rule is applied dynamically to an on-screen target preview element. Rendering uses native browser compositor pipelines, ensuring fluid 60 FPS slider interactions while maintaining sub-pixel accuracy.

Client-side security for private application UI design

ToolJiffy processes all shadow configuration controls and CSS code generation directly on your local device. Your interface design parameters, brand hex colors, and stylesheet definitions remain entirely confidential and never touch cloud infrastructure.

This client-side architecture allows frontend engineers and UI designers to safely work on proprietary dashboard layouts, unreleased mobile web apps, and enterprise design systems with total privacy.

Step-by-step guide to designing CSS box shadows

Adjust spatial offset & blur: Drag the Offset X, Offset Y, Blur, and Spread sliders to set the shadow's direction and soft edges.
Configure color and opacity: Choose your shadow color and adjust the opacity slider to dial in subtle elevation.
Copy production CSS: Click the copy button to grab the formatted box-shadow declaration and paste it into your CSS rules.

Explore related CSS design and layout tools

Enhance your interface design by creating smooth background fills with the CSS Gradient Generator, building UI keyframe effects with the CSS Animation Generator, arranging elements with the CSS Flexbox Generator, or sampling brand colors using the Color Picker.

Frequently Asked Questions

What do offset-X and offset-Y mean in CSS box shadows?
Offset-X determines the horizontal position of the shadow (positive values shift right, negative values shift left). Offset-Y determines the vertical position (positive values push down, negative values push up), controlling simulated light source angles.
What is the difference between blur radius and spread radius?
Blur radius controls how soft and feathered the shadow edge appears (0px creates a hard shadow). Spread radius expands or contracts the physical dimensions of the shadow shape before blur is applied, expanding or shrinking its footprint.
How do I create an inner shadow (inset) using CSS?
To create an inner shadow that appears inside element borders (common for text inputs and pressed buttons), add the inset keyword to the beginning of your box-shadow CSS property (e.g., box-shadow: inset 0px 2px 4px rgba(0,0,0,0.1)).
How can I layer multiple box shadows on a single element?
CSS allows comma-separated shadow definitions on a single property (e.g., box-shadow: 0 1px 3px rgba(0,0,0,0.1), 0 10px 20px rgba(0,0,0,0.05)). Layering a sharp tight shadow with a soft wide shadow creates photorealistic material elevation.
Does using heavy box shadows affect website performance?
Extremely large blur radii or animating box-shadow during page scrolling can trigger GPU layer re-paints. For smooth 60fps animations, animate opacity or transform on pseudo-elements instead of directly animating large box-shadow blur values.
Why are RGBA colors used instead of HEX for box shadows?
RGBA allows precise control over alpha transparency (e.g., rgba(0, 0, 0, 0.15)). Using semi-transparent shadows ensures the shadow blends naturally over varying background colors and images without creating harsh black smudges.
Are my custom box shadow configurations stored on any server?
No. All shadow calculations and CSS rendering happen strictly within your local web browser session. ToolJiffy does not collect, log, or transmit any design properties or generated code snippets to remote servers.
Is this CSS box shadow generator completely free to use?
Yes! The ToolJiffy CSS Box Shadow Generator is 100% free with unlimited usage, zero account registration requirements, no subscription paywalls, and no watermarks for all personal and commercial web projects.