CSS Blob Shape Generator

Create, customize, and export beautiful blob shapes for your website

Blob Complexity
Simple 5 Complex
Size Customization
100px 250px 400px
100px 250px 400px
Smoothness Control
Jagged 50% Smooth
Color & Gradient
0° 135° 360°
Border & Shadow
Effects & Animation
Multiple Layers
10% 50% 100%
110% 120% 150%
Randomize
Display Mode
Generated CSS Code

                        

                        

                            

                                
Generated SVG Code

                                

                                    
                                    
                                

                            

                            

                        

                    

                

                
                
                

                    
CSS Blob Implementation Guide

                    
                    

                        How This Generator Works: This tool creates organic shapes using CSS border-radius with 8 individual corner values, simulating SVG-like path distortion. The algorithm generates random control points around a circular path, with smoothness controlling the deviation amplitude.
                    

                    
                    
When to Use CSS Blobs vs SVG

                    
CSS Blobs (border-radius method): Best for performant, animated organic shapes that need CSS transitions or animations. Lightweight for UI elements that resize responsively. Limited to convex shapes with continuous curves.

                    
SVG Blobs: Recommended for complex concave shapes, detailed illustrations, print media, or when you need perfect scaling at any resolution. SVG offers more precise path control but requires different animation techniques.

                    
                    
Browser Compatibility

                    

                        
                            

                                Feature
                                CSS Border-Radius
                                CSS Animations
                                CSS Gradients
                            

                        
                        
                            

                                Chrome 4+
                                Full Support
                                Full Support
                                Full Support
                            

                            

                                Firefox 3+
                                Full Support
                                Full Support
                                Full Support
                            

                            

                                Safari 5+
                                Full Support
                                Full Support
                                Full Support
                            

                            

                                Edge 12+
                                Full Support
                                Full Support
                                Full Support
                            

                        
                    

                    
                    
Performance Considerations

                    
Animation Performance

                    
Animating border-radius triggers CSS paint operations. For 60fps animations:

                    
    
                        
  • Keep animation duration ≥ 100ms for subtle morphing
    • 
                        
  • Avoid animating more than 3-4 blobs simultaneously on mobile
    • 
                        
  • Consider using transform for scale/position animations instead of border-radius when possible
    • 
                    

                    
                    
Rendering Optimizations

                    
For complex blobs (8+ curves), apply will-change: border-radius; to hint browser optimizations:

                    
.blob {
  will-change: border-radius;
  /* Only use when animating */
}

                    
                    
Accessibility Guidelines

                    
    
                        
  • Ensure sufficient color contrast between blob and background (4.5:1 minimum)
    • 
                        
  • For animated blobs, provide a reduced motion option using @media (prefers-reduced-motion)
    • 
                        
  • Decorative blobs should have aria-hidden="true" or role="presentation"
    • 
                        
  • If blobs convey information, provide text alternatives
    • 
                    

                    
                    
Integration in Projects

                    
Direct CSS Implementation

                    
Copy the generated CSS into your stylesheet. For responsive designs:

                    
/* Use relative units for responsive blobs */
.blob-container {
  width: min(300px, 90vw);
  aspect-ratio: 1; /* Maintain shape */
}

/* Or use viewport units */
.responsive-blob {
  width: 20vw;
  height: 20vw;
  max-width: 300px;
  max-height: 300px;
}

                    
                    
React/Vue Component Example

                    
// React component with dynamic blob
function DynamicBlob({ complexity, smoothness }) {
  const borderRadius = generateBlobCSS(complexity, smoothness);
  
  return (
    <div 
      className="blob"
      style={{ 
        borderRadius,
        background: 'linear-gradient(135deg, #667eea, #764ba2)'
      }}
    />
  );
}

                    
                    
Common Mistakes & Solutions

                    

                        
Blob loses shape on resize

                        
Solution: Use aspect-ratio: 1 or maintain equal width/height percentages. CSS border-radius values are percentage-based relative to each dimension.

                    

                    
                    

                        
Animation appears jaggy on mobile

                        
Solution: Reduce complexity (3-5 curves), increase smoothness (60%+), or use SVG with CSS transforms instead of border-radius animation.

                    

                    
                    

                        
Gradient doesn't match blob shape

                        
Solution: CSS gradients fill the bounding box, not the blob shape. For gradient following contour, use SVG with gradient fills or CSS mask with gradient background.

                    

                    
                    
Tool Limitations & Scope

                    
    
                        
  • Generates convex shapes only (no holes or concave curves)
    • 
                        
  • Maximum 12 control points for performance
    • 
                        
  • CSS output uses 8-value border-radius syntax (not all browsers support >4 values equally)
    • 
                        
  • SVG output includes basic attributes only (no advanced filters or patterns)
    • 
                    

                    
                    
Related CSS Tools

                    
For more advanced shape generation, explore our CSS zig zag border Generator for complex polygons, or the CSS Gradient Generator for advanced gradient configurations.

                    
                    

                        Privacy & Processing: All shape generation occurs locally in your browser using JavaScript. No images or code are uploaded to external servers. Generated CSS/SVG is immediately available for copy-paste into your projects.
                    

                    
                    
Last updated: March 2025 | Compatibility verified for modern browsers (Chrome 90+, Firefox 88+, Safari 14+, Edge 90+)