Interior Design Calculators
Baseboard Trim Calculator
Calculate the linear feet of baseboard trim needed for a room by subtracting door opening widths from the total room perimeter.
Blinds Inside Mount Calculator
Calculate the correct blind width for an inside mount installation by subtracting the necessary hardware clearance from the window width.
Chandelier Size Calculator
Calculate the recommended chandelier or pendant light diameter for a room using the standard designer sum-of-dimensions rule.
Closet Rod Length Calculator
Calculate the total closet rod length needed based on the number of garments and average hanging space per garment.
Curtain Fabric Calculator
Calculate the fabric yardage and panel count needed for curtains from window size, fullness ratio, hem allowance, and fabric bolt width.
Curtain Rod Length Calculator
Calculate the ideal curtain rod length from window width and side extension so curtains stack fully open without blocking light.
Furniture Layout Calculator
Calculate clear floor space and an estimated walkway width after furniture placement, compared against standard clearance guidelines.
Furniture Scale Calculator
Convert an actual furniture or room dimension into a scaled drawing dimension for a floor plan using a chosen scale ratio.
Interior Design Space Planner
Calculate what percentage of a room's floor area is used by furniture and how much open space remains, against a comfortable-layout guideline.
Interior Lighting Design Calculator
Calculate the total lumens needed for a room's general lighting based on its area and a recommended foot-candle level for that room type.
Lumen Requirement Calculator
Calculate the total lumens needed for a room from its area and a custom required foot-candle lighting level for any use case.
Paint Quantity Calculator
Calculate the gallons of paint needed for a room from total wall area, door and window area to subtract, and the number of coats.
Picture Frame Mat Calculator
Calculate the overall mat board size needed for a picture frame from the image dimensions and desired border width.
Room Color Scheme Calculator
Generate complementary, triadic, analogous, split-complementary, or tetradic color scheme hues from a single base color hue value.
Rug Size Calculator
Find the largest standard area rug size that fits a room while leaving a recommended floor border between the rug edge and the walls.
Table Runner Length Calculator
Calculate the ideal table runner length from table length and desired overhang so the runner drapes proportionally on each end.
Throw Pillow Size Calculator
Calculate the recommended throw pillow size proportional to your sofa's seat depth, rounded to the nearest standard insert size.
Tile Flooring Quantity Calculator
Calculate how many floor tiles you need from floor area, tile size, and a waste allowance for cuts and breakage.
Wall Art Spacing Calculator
Calculate the even gap width needed to space multiple art pieces evenly across a wall based on wall width and each piece's width.
Wallpaper Roll Calculator
Calculate how many wallpaper rolls you need from wall area, roll dimensions, and a waste allowance for pattern matching.
Designing a Room That Works
Good interior design is partly aesthetic judgment and partly straightforward measurement — enough lighting for the room's function, enough fabric for the windows, furniture scaled to the actual floor space. These ten calculators cover that measurement side.
How Many Lumens a Room Actually Needs
- Find the room's square footage. Multiply length by width in feet.
- Match the room type to its foot-candle requirement. A kitchen or workspace typically needs 30-40 foot-candles for task lighting; a bedroom or living room typically needs only 10-20 for general ambient light.
- Multiply square footage by foot-candles needed. A 150 sq ft kitchen at 35 foot-candles needs roughly 5,250 lumens of light output total.
- Split that total across fixtures. Divide the lumen target by the number of planned fixtures, then check each fixture or bulb's rated lumen output against that per-fixture target.
Run this directly with the Lumen Requirement Calculator, or plan layout first with the Furniture Layout Calculator.
Popular Interior Design Calculators
- Curtain Fabric Calculator — calculates fabric yardage needed from window dimensions and desired fullness.
- Rug Size Calculator — recommends rug dimensions based on room size and furniture arrangement.
- Room Color Scheme Calculator — suggests complementary color palettes based on a chosen base color.
Related: Home Improvement Calculators for larger renovation projects.