Responsive Grid Calculator
A responsive grid calculator that takes total width, column count, and gutter size to output perfect CSS Grid or Flexbox layouts. Essential for designers and developers building responsive card grids, product galleries, or multi-column layouts. Enter your container dimensions and preferences to see exact column widths, total gutter space, and production-ready CSS code. All calculations happen in your browser with no uploads required. It is ideal for designers and marketers who want polished assets without opening heavyweight software. Tweak settings, preview changes instantly, then export and download in a clean format. Everything runs in your browser, so your files stay on your device. Built for speed, clarity, and repeat use.
Visual Preview
Column Width
0px
Total Gutters
0px
Content Width
0px
CSS Code
How to Use This Tool
- Enter your container width in pixels, number of columns (1-24), and gutter size between columns
- Choose CSS Grid or Flexbox as your layout system to see different code approaches
- Copy the generated CSS which includes utility classes for spanning multiple columns in your layout
Why This Method?
Modern responsive layouts require precise math to distribute space evenly across columns while accounting for gutters. CSS Grid uses the gap property and 1fr units to handle this automatically, while Flexbox requires manual calculations like calc((100% - gutterTotal) / columns). This tool does the math for you and outputs both approaches.
The generated code includes span classes for creating flexible layouts where some items take 2, 3, or 4 columns. CSS Grid handles this with grid-column: span N, while Flexbox uses width calculations that account for the extra gutter space consumed by wider items. Understanding these patterns is key to building production-quality responsive layouts.