How to Measure for Roman Shades? 5 Mistakes to Avoid (Inside & Outside)
If you are getting ready to order custom Roman Shades for your home, put down that measuring tape first! People often ask us, "how do you measure for roman shades without messing up?" As a senior interior designer with over a decade of experience in the custom window treatment industry, I have personally guided hundreds of homeowners through the measurement and installation process. After analyzing thousands of customer reviews and return logs, we discovered a brutal truth: 90% of measurement disasters occur because of tiny, yet fatal, errors during the measuring phase.
Whether you prefer the classic, privacy-focused look of our Custom Linen Roman Shades (Blackout & Cordless Options) or the effortlessly elegant, French-inspired Harper Custom Relaxed Linen Roman Shades, a flawless installation always relies on accurate measurements. Different fabric drapes and stack heights dictate strict requirements for window frame space.
To ensure you don't repeat these common errors, we have combined the strictest industry standards with our professional team's decade of hands-on experience solving complex window layouts. This comprehensive guide on how to measure for roman shades will provide you with all the expert knowledge you need, saving you from costly trial-and-error mistakes.
Table of Contents
Part 1: Choosing Inside vs. Outside Mount Roman Shades
Before figuring out exactly how to measure windows for roman shades, you must first decide on your mounting type. This decision depends on your window depth, opening direction, and light control preferences.
| Comparison Factor | Inside Mount | Outside Mount |
|---|---|---|
| Mounting Location | Installed inside the window frame for a clean, built-in look. | Installed on the wall or molding above the window frame, covering the entire window. |
| Visual Effect | Minimalist and tailored. Perfectly showcases beautiful window moldings. | Makes windows appear larger, hides ugly frames, and provides better light control. |
| Space & Depth Requirements | The inside of the frame must be flat, and the depth must be at least 2.5 inches to perfectly accommodate the headrail. | No depth requirement. Ideal for shallow window frames or windows with crank handles and locks. |
| Compatible Window Types | Sliding windows, outward-opening windows. (Note: Inward-opening windows cannot use inside mount.) |
Sliding, outward-opening, and inward-opening windows can all use this style. |
| Light Control | Will have slight light gaps on the sides. | Excellent blackout capabilities, as the fabric width can be extended to cover the entire window opening. |
Part 2: How to Measure for Roman Shades (Step-by-Step)
Once you've decided on your mounting style, grab a steel tape measure and follow these industry-standard steps to learn how to measure for a roman shade correctly:
1. How to Measure for Roman Shades Inside Mount
The key to a successful inside mount is dealing with out-of-square windows and accurately capturing the minimum dimensions.
- Measure the Width: Measure the inside width of the window frame at three places: top, middle, and bottom. Record the smallest measurement as your order width.
- Measure the Height: Measure the vertical height on the left, middle, and right sides. Record the largest measurement as your order height.
Note: Provide the exact net dimensions of your window frame. The factory will automatically deduct a standard 3/8 inch from the width to ensure the shade operates smoothly without rubbing against the frame.
2. How to Measure for Outside Mount Roman Shades
The secret to a perfect outside mount is calculating the right overlap to prevent light leakage and allowing enough room for the roman shade stack height.
- Measure the Width: Measure the total width you want to cover. To minimize light leakage, we recommend adding 2 to 4 inches to each side (meaning you add 4 to 8 inches to your total width).
- Measure the Height: Measure the total height from the installation point down to where you want the bottom hem to fall. To allow clearance for the shade when fully raised, we strongly recommend adding 10 to 12 inches above the window frame for the headrail installation.
If adding and subtracting fractions makes your head spin, we highly recommend using Morrahome's Measurement Finder. This interactive calculator is perfect for beginners. Just enter your exact window frame measurements, select inside or outside mount, and it will automatically calculate the necessary deductions or overlaps for you. You get the perfect final dimensions ready for checkout, completely eliminating the anxiety of making a math error!
Part 3: Top 5 Measurement Mistakes to Avoid
If you prefer to crunch the numbers yourself, make sure you avoid these 5 common pitfalls when learning how to measure roman shades:
Why it fails: This is the most common error for inside mounts. Customers manually deduct fractions from their width, resulting in huge light gaps when the product arrives.
✅ The Fix: Follow the inside mount deduction rules. You only need to provide the "exact net size" of the window frame. The factory will automatically deduct the 3/8-inch clearance. Do not do the math yourself!
Why it fails: Measuring the width only once at the bottom. The window might be narrower at the top, causing the shade to get stuck when raised.
✅ The Fix: Strictly follow the 3-point measurement rule. For inside mounts, always use the narrowest width and the tallest height.
Why it fails: Measuring the frame but forgetting about window depth. The shade sticks out awkwardly from the wall, looking bulky and collecting dust.
✅ The Fix: When measuring depth, account for any protruding window cranks or locks. Your available clear depth must be at least 2.5 inches. If it's shallower, switch to an outside mount!
Why it fails: Choosing an outside mount but ignoring the fabric stack. When fully raised, the thick fabric stack blocks a quarter of your window glass.
✅ The Fix: When figuring out how to measure outside mount roman shades, move your installation point up! Allow 10 to 12 inches of space above the window molding so the raised shade rests perfectly on the wall without blocking natural light.
Why it fails: Cloth tapes stretch, leading to errors of an inch or more.
✅ The Fix: In the battle of steel tape measure vs. cloth, steel is the only winner. It is the industry standard for custom window treatments. Ensure your measurements are precise to the nearest 1/8 inch.
Part 4: Frequently Asked Questions (FAQ)
Q: Is there a difference between measuring for roller shades and measuring for roman shades?
A: While the basics are similar, roman shades have a much thicker fabric stack height. Therefore, when people ask how do you measure for outside mount roman shades, we always emphasize adding an extra 10-12 inches above the window frame to avoid blocking the glass, which isn't always necessary for slim roller shades.
Q: My window depth is only 1.5 inches. Can I still do an inside mount?
A: We do not recommend it. The headrail hardware and folding fabric require at least 2.5 inches to sit flush inside the frame. A shallow inside mount will cause the headrail to stick out, creating ugly side gaps. If people ask us how to measure for roman shades outside mount in this scenario, we guide them through the outside mount process instead.
Q: How do I measure the height if my window has a protruding sill?
A: For an inside mount, measure down to the surface of the window sill. For an outside mount where the sill sticks out from the wall, we recommend measuring the height so the bottom edge of the roman shade rests exactly on top of the protruding sill. This prevents the fabric from bunching up.
Q: I want 100% blackout. Which mount is better?
A: For the absolute best light-blocking performance, an outside mount is highly recommended. Inside mounts will always have a slight "light halo" on the sides due to the necessary hardware deductions. By learning how to measure roman shades outside mount and adding 2 to 4 inches of overlap on all sides, you effectively block light from entering through those side gaps.
Summary:
Measuring for Roman Shades isn't difficult once you know the rules. As an experienced team, our goal with this guide is to give you clarity and confidence. By avoiding the common pitfalls and respecting industry standards—like the 2.5-inch depth rule and proper factory deductions—you can achieve beautifully tailored window treatments. If you have any questions about measuring oddly shaped windows, drop a comment below and our experts will help you out!