About

Last updated: 2026-06-25

What is InteriorCalc

InteriorCalc is a free collection of tools that help people planning DIY interior work figure out how much material to buy, quickly and accurately. Just enter your area and instantly see wallpaper rolls, paint amount (L), tile count, and flooring boxes as quantities that already include waste.

Operating principles (E-E-A-T)

• Experience — We reflect the units used in real material purchases (rolls, liters, tiles, boxes) and the waste-rate concept, and break results down item by item.
• Expertise — We calculate using a consistent formula, "installation area × (1 + waste rate) ÷ coverage per unit," and typical material specs.
• Authoritativeness — We state the coverage per unit and recommended waste rate, and remind you to confirm the product spec.
• Trustworthiness — We never hide the formula, and we make clear that all figures are reference estimates. Your inputs are not collected or stored.

Calculation basis

The defaults used in each calculator are based on commonly accepted material specs. Because they vary by product, they are marked as "adjustable" so you can change them yourself.

• Wallpaper — Coverage per roll about 16.5 m² (vinyl), default waste rate 10%.
• Paint — Water-based coverage rate about 10 m²/L (one coat), default waste rate 5%.
• Tile — Area of one tile = (width mm ÷ 1000) × (height mm ÷ 1000), default waste rate 10%.
• Flooring — Coverage per box (roll) about 3.3 m², default waste rate 5%.

A note on accuracy

All InteriorCalc results are reference estimates based on your inputs and typical specs. The real amount of material needed can vary with the product spec, space shape, layout pattern and method, and installer skill, so please confirm with product spec sheets and a contractor's quote before buying.

Contact

Send suggestions for improvement or error reports to jin@zerolabskorea.com. For how we handle personal data, see our Privacy Policy.

Last updated: 2026-06-25