Free tools
Calculators for interior designers
The math you do every week — markups, fees, yardage, gallons — as free interactive tools. No signup, no spreadsheet, no mental arithmetic at 6 pm.
Pricing
Markup & margin calculator
Markup and margin are not the same number — a 35% markup is only a 26% margin, and mixing them up quietly underprices your product. Enter your cost and markup to see the client price, or find the markup you need for a target margin.
Margin = profit ÷ selling price. Markup = profit ÷ cost. To hit a margin of M%, mark up by M ÷ (100 − M) × 100.
Your business
Billable hourly rate calculator
Your rate has to cover more than your salary — overhead, unbillable hours, and profit all come out of it. This tells you the minimum rate that actually supports your firm.
Overhead includes rent, software, insurance, marketing, and non-billable staff time. Most designers realistically bill 20–30 hours a week — the rest is running the firm.
Proposals
Design fee estimator
A sanity-check range for flat fees, based on typical hours per room by scope. Use it as a starting point, then refine with your own time data.
Hours per room vary with client decisiveness, custom work, and revision rounds. Firms that track time against phases price the next project from evidence, not instinct.
Workroom does this math for you, automatically
Markups applied the moment you clip a product. Time tracked against fees. Live margin on every project. These calculators are the manual version of what Workroom does all day.
Book a demoSpecification
Paint calculator
How many gallons for the walls of a room, accounting for doors, windows, and coats.
Assumes 350 sq ft coverage per gallon, 21 sq ft per door, and 15 sq ft per window. Walls only — add separately for ceiling and trim. Dark or dramatic color changes may need an extra coat.
Specification
Wallpaper calculator
Rolls needed for a wall or room, including the waste from matching a pattern repeat — the part everyone underestimates.
Includes a 4" trim allowance per strip and rounds each strip up to a full pattern repeat. Order all rolls from the same dye lot, and confirm quantities with your installer before purchasing — for large repeats or grasscloth, add a safety roll.
Specification
Flooring & tile calculator
Material to order including waste — cuts, breakage, and pattern matching — plus budget if you add a price.
For L-shaped or irregular rooms, split the space into rectangles and add the areas. Round up to full boxes when ordering — leftover material is your future repair stock.
Specification
Rug size calculator
The right standard rug size for a room, keeping a proper border of visible floor.
Based on an 18-inch border of visible floor on each side, snapped to standard rug sizes (5×8 through 12×18). Custom and round sizes follow the same border rule.