All tools

Interior design calculators & tools

Every DID calculator in one place — 9 free, standards-based tools that give you an instant, measurement-driven answer. No sign-up, and nothing you enter ever leaves your browser.

Rug Size Finder Find the ideal standard rug footprint (8×10, 9×12 and more) from your room dimensions and furniture layout. Open tool → Furniture Clearance Check walkways and pinch points against the mandatory 30-inch clearance path for comfortable, code-friendly circulation. Open tool → TV Viewing Distance Use SMPTE & THX field-of-view math to size your TV and set the perfect wall-mount height. Open tool → Room Lumens Calculate exact LED lumen demand and foot-candle targets for any room type and activity. Open tool → Recessed Lighting Determine symmetrical can-light spacing and wall offsets for even, clean ceiling layouts. Open tool → Gallery Wall Spacer Get fraction-of-an-inch spacing and center lines for a balanced, professional gallery wall. Open tool → Art Hanging Height Enforce the universal 57-inch museum center line and get the exact hook height for any frame. Open tool → Curtain Length Compute drapery length and rod height that visually maximize ceiling height, with a live preview. Open tool → 60-30-10 Color Split a room’s surface area into balanced dominant (60%), secondary (30%) and accent (10%) color zones. Open tool →