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About InteriorPro
Your global interior renovation calculator suite
InteriorPro is a comprehensive, free online tool designed to help homeowners, DIY enthusiasts, interior designers, and contractors plan interior renovation projects with confidence. Whether you're painting a single room, laying new flooring throughout your home, tiling a bathroom, or wallpapering a feature wall, InteriorPro provides instant, accurate calculations so you can order the right amount of materials — no waste, no shortage.
Our mission is simple: take the guesswork out of home renovation math. We support four languages (English, Japanese, Spanish, and Korean) and three unit systems (Metric, Imperial, and Japanese) so users around the world can get precise results in the units they actually use every day.
Who Is InteriorPro For?
InteriorPro is built for anyone planning a renovation or interior update:
- Homeowners planning a DIY paint job or flooring installation — know exactly how much material to buy before you visit the store.
- Interior designers preparing client estimates — create accurate material lists and budget projections in minutes.
- Contractors and builders quoting renovation projects — generate professional cost estimates for clients across different quality tiers.
- Real estate agents advising clients on renovation ROI — quickly estimate the cost and scope of potential improvements.
- Expats and international homeowners working with local contractors in a different unit system — convert seamlessly between metric, imperial, and Japanese measurements.
What Makes InteriorPro Different?
- 6 integrated calculators covering every major renovation material: paint, flooring, tile, wallpaper, area measurement, and unit conversion.
- Multilingual interface — switch between English, 日本語, Español, and 한국어 with one click.
- Multi-unit support — work in metric (m²), imperial (sq ft), or Japanese (tsubo/jo) systems side by side.
- Real cost estimates — get per-square-unit renovation costs for the US, Europe, Japan, and Korea, updated from industry averages.
- Comprehensive reference data — standard furniture dimensions, door/window sizes, electrical fixture heights, and a style guide with 7 interior design styles.
- Shareable results — each calculator generates a shareable link so you can save your calculations or send them to a contractor.
InteriorPro runs entirely in your browser. No data is sent to any server, no account is required, and there are no ads interrupting your workflow. We believe renovation tools should be fast, free, and private.
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Features
Everything you need to plan your renovation
📐 Unit Converter
Convert between square meters (m²), square feet (sq ft), tsubo, and jo instantly. Perfect for international projects where architectural plans use different units. Simply enter a value, select your source and target units, and get the conversion in real time.
📏 Area Calculator
Calculate the floor area of any rectangular room by entering width and length. Results display in m², sq ft, tsubo, and jo simultaneously so you can compare across unit systems. Essential first step before calculating paint, flooring, or tile quantities.
🎨 Paint Calculator
Determine exactly how much paint you need for any room. Enter room dimensions, number of doors and windows (standard deductions apply), and choose your number of coats. The calculator accounts for: wall area minus openings, paint coverage rate per liter/gallon, and standard can sizes (from 1L to 10L). Never overbuy paint again.
🪵 Flooring Calculator
Calculate how many boxes of flooring material you need for any room. Supports three material types: laminate flooring, engineered hardwood, and luxury vinyl planks (LVP). Account for waste factor (default 10%, adjustable up to 20% for diagonal installations or complex layouts). Each material type has accurate coverage per box with typical box sizes pre-configured.
🔲 Tile Calculator
Plan your tiling project with precision. Choose from standard tile sizes (10×10 cm up to 60×60 cm), set your grout gap width (1-5 mm), adjust the waste factor for breakage and cuts, and select your laying pattern (straight grid or diagonal). Diagonal patterns automatically apply a higher waste rate. Results show total tiles needed, plus tiles per square meter for easy price estimation.
📜 Wallpaper Calculator
Calculate the exact number of wallpaper rolls needed for any room. Enter room dimensions plus number of doors and windows. Choose between standard rolls (0.53 m × 10 m, covers ~5 m²) and wide rolls (1.06 m × 15.7 m, covers ~16 m²). Account for pattern matching: no match, straight match (20 cm offset), or drop match (64 cm offset) — pattern matching significantly increases material requirements.
💰 Cost Estimator
Get realistic renovation cost estimates for four major regions: United States (USD per sq ft), Europe (EUR per m²), Japan (JPY per tsubo), and Korea (KRW per pyeong). Select your renovation type (full renovation, kitchen, or bathroom), choose quality tier (budget, standard, premium), and adjust for your local market conditions. The estimator uses up-to-date industry averages compiled from 2026 renovation cost data.
📋 Reference Library
Access a comprehensive database of standard dimensions: furniture sizes (beds 90-180 cm wide, sofas 180-300 cm, dining tables 140-200 cm), door and window standard sizes, electrical fixture installation heights (switches at 105 cm, outlets at 30 cm), kitchen counter depths (60 cm standard, 90 cm for island), bathroom fixture clearances, and more. Plus a visual style guide covering 7 popular interior design styles with material palettes, color schemes, and key characteristics.
Every feature is fully translated into 4 languages with appropriate unit handling. Switch languages mid-calculation without losing your inputs. Share any calculation result with a single click. All calculations run locally in your browser — zero server calls, zero data storage.
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How to Use InteriorPro
Step-by-step guide for every calculator
Getting Started
From the main screen, select your preferred language and unit system from the top-right dropdowns. The interface will update immediately. Choose a calculator tab (on mobile, scroll the bottom tab bar; on desktop, all calculators are visible in a grid).
Using the Paint Calculator
Enter your room's width, length, and ceiling height in your chosen units. Specify the number of doors and windows to deduct their approximate area. Select the number of coats (1-3). Click "Calculate Paint" to see: total wall area in m² or sq ft, total paint needed in liters or gallons, and the most cost-effective can size combination to buy.
Using the Flooring Calculator
Enter the room's width and length. Choose your flooring type (laminate, hardwood, or vinyl). Adjust the waste percentage (10% is standard for straight layouts; increase to 15-20% for diagonal or complex layouts). Select the box coverage if your product differs from the default. Click calculate to see: total area, boxes needed (rounded up), and total coverage including waste.
Using the Tile Calculator
Enter the tiling area dimensions. Select your tile size from the dropdown (custom sizes coming soon). Set your grout gap (standard is 2-3 mm for wall tiles, 3-5 mm for floor tiles). Choose your laying pattern — "Diagonal" automatically increases waste to 15%. Click calculate to see: exact number of tiles needed, tiles per square meter, and total area covered.
Using the Wallpaper Calculator
Enter room dimensions (width, length, height). Add doors and windows for deductions. Choose roll type: standard (0.53 m × 10 m) or wide (1.06 m × 15.7 m). Select pattern matching: "No match" for solid colors or random patterns, "Straight match" for simple repeat patterns, "Drop match" for complex designs. Drop match requires the most material due to pattern offset waste.
Using the Cost Estimator
Navigate to the Cost tab. Select your country/region. Enter your project area in your chosen units. Choose the work type (full renovation, kitchen renovation, or bathroom renovation). Select quality tier (budget, standard, or premium). Use the adjustment slider (±50%) to fine-tune for your local market. The estimate breaks down by category: full renovation cost per unit, kitchen, and bathroom.
Sharing Results
Each calculator has a "Copy Link" button. Click it to copy a URL that encodes your current inputs and settings. Paste this link in an email, message, or note to share your calculations with a contractor, designer, or save them for later. When you open the link, all values are restored automatically.
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Frequently Asked Questions
Common questions about InteriorPro and renovation planning
Q: Are the calculations accurate enough for ordering materials?
Yes. Our calculators use industry-standard formulas and coverage rates. For paint, we use 10 m² per liter (metric) or 350 sq ft per gallon (imperial) — standard rates used by major manufacturers. For flooring and tile, we factor in waste (cuts, breakage, pattern matching) that professional installers use. Always buy 5-10% extra for offcuts and future repairs.
Q: Do I need an account or to sign up?
No. InteriorPro requires no account, no email, no sign-up. All calculations run entirely in your browser. Nothing is sent to any server. Your privacy is built into the design — we collect zero personal data.
Q: Can I save my calculations?
Yes! Use the "Copy Link" button on any calculator to generate a URL that encodes your current inputs. Save this link in your notes, bookmark it, or share it with your contractor. When you open the link later, all your values are restored.
Q: Which unit systems are supported?
Three unit systems: Metric (m², L, m), Imperial (sq ft, gal, ft), and Japanese (tsubo, jo). You can switch between them at any time without losing your input values — the app converts them automatically.
Q: Which languages are available?
Four languages: English, Japanese (日本語), Spanish (Español), and Korean (한국어). Switch languages instantly from the top-right dropdown. All calculator labels, results, reference data, and navigation are fully translated.
Q: How accurate are the cost estimates?
Cost estimates are based on 2026 industry averages for the US, Europe, Japan, and Korea. Actual costs vary significantly by city, contractor, material quality, and project complexity. Use the adjustment slider (±50%) to fine-tune for your local market. We recommend getting at least 3 quotes from local contractors for final budgeting.
Q: What's the difference between a standard and wide wallpaper roll?
Standard wallpaper rolls are 0.53 meters wide by 10 meters long (covering approximately 5 m² per roll). Wide rolls (also called "European" or "contract" rolls) are 1.06 meters wide by 15.7 meters long (covering approximately 16 m² per roll). Wide rolls have fewer seams and are faster to install but require more careful pattern matching.
Q: Why do I need to account for waste in flooring and tile?
Waste accounts for material lost to cuts around corners, doorways, obstacles, and inevitable breakage during installation. For straight-lay flooring, 10% waste is standard. Diagonal layouts and complex room shapes require 15-20%. Tile breakage during cutting adds 5-15% depending on installer skill. Never order the exact calculated area — always add waste.
Q: Is InteriorPro free?
Yes, completely free. There are no paid tiers, no premium features, no subscription. We support the site through non-intrusive advertising. If you find the tool useful, sharing it with a friend who's planning a renovation is the best way to support us.
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Interior Renovation Tips
Professional advice from experienced renovators
Planning
Measure Twice, Order Once
Always measure every wall in at least two places — walls are rarely perfectly square. Use the largest measurement for ordering materials. A 1 cm error over a 4 m wall is 0.25% error, but a 5 cm error in a non-square room can eat into your waste buffer fast.
Paint
Primer Saves Paint
A good primer coat can reduce your paint consumption by 20-30% on new drywall or dark walls. Most calculators (including ours) assume painted or primed surfaces. If you're painting raw drywall or a dramatic color change, always do a primer coat first and add an extra coat of paint.
Flooring
Acclimate Your Flooring
Laminate, hardwood, and vinyl planks need to acclimate to the room's temperature and humidity for at least 48 hours before installation. Stack boxes in the center of the room, open them, and let the material adjust. Failing to acclimate is the #1 cause of post-installation gaps and buckling.
Tile
Buy From the Same Batch
Tiles from different production batches can have slight color variations. Always buy all your tiles from the same batch number (printed on the box). Order 10-15% extra — you can return unopened boxes, but matching a batch later is nearly impossible.
Wallpaper
Order Extra for Matching
Patterned wallpaper requires significantly more material than solid colors. A drop-match pattern (where the design repeats both horizontally and vertically) can waste up to 40% of each roll in offcuts. Always buy an extra roll for large patterns — running out mid-project means mismatched batches.
Budget
30% Budget Buffer
Set aside 30% of your total renovation budget for unexpected issues: found water damage, outdated wiring discovered during demolition, structural surprises, or mid-project scope changes. Even a small renovation almost always reveals something behind the walls.
Planning
Finish Materials First
Final flooring, paint, and tile choices should be made before demolition begins. Lead times for some materials (especially imported tile or specialty flooring) can be 4-8 weeks. Nothing extends a renovation timeline like waiting for materials to arrive.
DIY
Know When to Hire a Pro
Painting and simple flooring installation are good DIY projects. Tiling, electrical work, plumbing, and structural changes are not. A poorly tiled shower can cause water damage costing 10× the installation price. Use the cost estimator to compare DIY material costs vs. professional quotes.
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Privacy Policy
Last updated: June 7, 2026
1. Information We Collect
InteriorPro does not require registration, account creation, or any personal information to use. We do not collect, store, or process your name, email address, phone number, or postal address. All calculator inputs (room dimensions, material choices, quality selections) are processed entirely in your browser using JavaScript and are never transmitted to any server.
2. Automatically Collected Information
When you visit InteriorPro, standard web server logs may record: your IP address, browser type and version, operating system, the referring page, pages visited on our site, and the date and time of your visit. This information is used for anonymous traffic analysis and to diagnose technical issues. We do not link this data to any individual user.
3. Cookies and Advertising
InteriorPro uses Google AdSense to display advertisements. Google and its partners use cookies (such as the DoubleClick DART cookie) to serve ads based on your visits to our site and other websites. You can learn more about Google's advertising practices and opt out of personalized advertising by visiting Google Ad Settings. You may also opt out of third-party vendor cookies through the Network Advertising Initiative opt-out page.
4. Third-Party Services
InteriorPro uses the following third-party services: Google AdSense (advertising). These third parties have their own privacy policies governing the use of your information. We do not control their data collection practices. We use a Content Delivery Network (CDN) to serve fonts — specifically, Pretendard font from jsdelivr CDN. The CDN may log your IP address as part of standard operations.
5. Data Retention
We do not store any personal data on our servers. Any information in web server logs is retained for a maximum of 30 days and then automatically deleted. No user profiles, calculation histories, or personal preferences are stored server-side.
6. Your Rights
Depending on your jurisdiction, you may have the right to: request access to any personal data we hold about you (we hold none by design), request deletion of your data, opt out of personalized advertising, and withdraw consent for cookie-based advertising via browser settings. To exercise these rights, contact us at the email address below.
7. Children's Privacy
InteriorPro is not directed at children under the age of 13. We do not knowingly collect any information from children. If you believe a child has provided us with personal information, please contact us immediately and we will take steps to remove that information.
8. Changes to This Policy
We may update this privacy policy from time to time. Changes will be posted on this page with an updated "Last updated" date. We encourage you to review this policy periodically. Continued use of InteriorPro after changes constitutes acceptance of the updated policy.
9. Contact
If you have questions about this privacy policy, please contact us at: all4authentic@gmail.com. We will respond to privacy-related inquiries within 30 days.