5 Quick & Easy Steps to Measure Windows * bigfinish.com

Measuring windows accurately is crucial for ensuring proper installation of blinds, curtains, or replacement windows. Precise measurements will prevent costly mistakes and ensure a seamless fit. Whether you’re a seasoned contractor or a DIY enthusiast, understanding the techniques for measuring windows is essential for any home improvement project. This comprehensive guide will provide you with step-by-step instructions, helpful tips, and industry-standard practices to guarantee flawless window measurements.

Before embarking on the measuring process, gather the necessary tools. You’ll need a measuring tape, a pencil or pen, and a notebook to record your measurements. Start by measuring the width of the window from the inside edge of the left frame to the inside edge of the right frame. Note this measurement and label it as the “window width.” Next, measure the height of the window from the inside edge of the top frame to the inside edge of the bottom frame. Label this measurement as the “window height.”

In addition to the window width and height, you may also need to measure the depth of the window frame. This measurement is particularly important for window treatments such as blinds or curtains. To measure the depth, place the measuring tape at the top of the window frame and extend it to the outside edge of the frame. Note this measurement and label it as the “window depth.” By following these simple steps and using the tips provided, you can ensure accurate window measurements that will lead to successful window treatments or replacements.

Determining Window Dimensions Using a Measuring Tape

Calculate the Width

Measure the Width at the Narrowest Point: Open the window by swinging it all the way to one side. Use the measuring tape to measure the width of the opening at its narrowest point, usually where the window meets the frame. Be sure to hold the tape straight and measure from the inside edge of the frame on one side to the inside edge of the frame on the other side. This will give you the rough width of the window, or the width of the opening, depending on your intention.

Vertical Measurements

Measure the Height at the Center: Keep the window open and switch the measuring tape to measure vertically. Hold the tape straight and measure from the bottom of the opening to the top of the opening at the center. Ensure the tape is perpendicular to the floor to obtain an accurate height measurement.

Horizontal Measurements

Measure the Length of the Bottom and Top: Measure the length of the bottom opening from left to right while keeping the tape parallel to the floor. Repeat this measurement for the top of the opening, again ensuring the tape is parallel to the floor. If the top and bottom lengths are different, note both measurements for later calculations.

Understanding Window Sizes and Units of Measurement

Types of Window Measurements

Understanding the different types of window measurements is crucial before you start measuring. The measurements commonly used in window sizing include:

Rough Opening (RO): The rough opening refers to the space in the wall where the window will be installed. It measures the height and width of the opening itself.
Window Size: This refers to the actual dimensions of the window frame, which is typically smaller than the rough opening.
Fin Frame: The fin frame is the part of the window that extends beyond the rough opening to cover the opening’s edges.

Units of Measurement

Window measurements are typically expressed in inches or feet. However, some manufacturers use millimeters or centimeters as well. It’s essential to ensure consistency in the units of measurement used throughout the measuring process.

To convert inches to feet, divide the inch measurement by 12. For example, 60 inches is equal to 5 feet.

Inches	Feet
60 inches	5 feet

To convert feet to inches, multiply the feet measurement by 12. For example, 5 feet is equal to 60 inches.

Measuring Window Width with Precision

1. Determine the Window Opening

Before you measure the window, determine the type of opening it has. Double-hung windows will require measuring both the upper and lower sash, while casement windows swing open on a hinge located on one side. Bay or bow windows consist of multiple window units; measure each unit separately.

2. Measure the Width of the Inside Frame

Use a measuring tape to measure the width of the window frame from the inside edge of one trim to the inside edge of the opposite trim. Be sure to measure in three locations: the top, middle, and bottom of the frame. Take note of any variations in the measurements and use the narrowest width to ensure an accurate fit.

3. Measuring the Width of the Outside Frame (Including Trim)

For a more precise measurement that includes the window trim, follow these steps:

Measurement Point	Instructions
A	Measure from the outside edge of one trim to the outside edge of the opposite trim.
B	Measure from the outside edge of the frame to the innermost edge of the trim on both sides.
C	Subtract measurement B from A. This value represents the combined width of the window frame and trim.

For example, if measurement A is 36 inches and measurement B is 1.5 inches on both sides, then measurement C would be 36 – (1.5 + 1.5) = 33 inches, indicating a window width of 33 inches including the trim.

Accurately Measuring Window Height

Measuring the height of a window may seem like a simple task, but it’s essential to do it accurately to ensure a proper fit for curtains, blinds, or other window treatments. Here are the steps to follow:

1. Determine the Type of Window

First, identify the type of window you’re measuring. Single-hung windows have one movable sash, while double-hung windows have two movable sashes. This will affect the measurement process.

2. Locate the Frame

Measure from the top of the window frame to the bottom, both on the inside and outside. The inside measurement will give you the height of the window itself, while the outside measurement will include the trim and molding.

3. Subtract Sashes (for Single-Hung Windows)

If you have a single-hung window, subtract the height of the movable sash from the inside measurement. This will give you the height of the window opening.

4. Determine Overlap (for Double-Hung Windows)

For double-hung windows, there is typically an overlap between the upper and lower sashes when closed. To account for this, measure the distance from the top of the upper sash to the bottom of the lower sash when closed. Multiply this measurement by 0.5 (assuming equal overlap) and subtract it from the inside measurement to get the height of the window opening.

5. Additional Considerations

Consider the following factors when measuring:

Factor	Description
Curtain rod placement	Measure higher if you want curtains to extend from the ceiling
Blinds width	Measure the width of blinds to ensure they cover the entire window opening
Window trim	Include trim and molding in measurements for a more precise fit

Calculating Window Area for Replacement and Design

Measuring windows accurately is crucial for replacing or designing new windows. Here’s a detailed guide to help you determine the correct window area:

Measuring the Width and Height

Use a measuring tape to measure the width and height of the window opening. Measure the width from the outer edge of one frame to the outer edge of the other. For the height, measure from the top of the frame to the bottom.

Allowing for Overlap

Subtract 1/2 inch from both the width and height to account for the overlap of the new window with the frame.

Calculating the Area

Multiply the adjusted width by the adjusted height to obtain the window area in square feet. For example, if the adjusted width is 32 inches and the adjusted height is 54 inches, the area would be 32 x 54 = 1,728 square inches or 12 square feet.

Determining Window Type and Style

The type and style of window you choose will affect the overall area. Here are some common types:

Type	Description
Single-hung	Upper sash moves up and down, while lower sash remains fixed.
Double-hung	Both sashes move up and down, allowing for ventilation from top and bottom.
Casement	Hinges on one side and cranks open like a door.
Awning	Hinges at the bottom and opens outward like an awning, providing ventilation during rain.
Slider	Horizontal or vertical sashes slide open to provide ventilation.

Considering Additional Factors

In addition to the basic measurements, consider the following factors that may impact the window area:

Trim and moldings: Allow for any trim or moldings around the window.
Insulation: If adding insulation around the window, factor in the additional space required.
Building codes: Some building codes may specify minimum window areas or ventilation requirements.

Measuring Irregularly Shaped Windows

Measuring irregularly shaped windows requires a slightly different approach than measuring standard rectangular or square windows. Here’s how to do it:

1. Identify the basic shape: Determine the overall shape of the window, such as an arch, triangle, or circle.

2. Divide into sections: Break down the window into smaller, simpler shapes, such as triangles, rectangles, or semicircles.

3. Measure the width and height of each section: Use a measuring tape or ruler to determine the dimensions of each individual shape.

4. Add up the measurements: Calculate the total width and height of the window by adding together the measurements of each section.

5. Consider the frame: If the window has a frame, measure the exterior dimensions of the frame to determine the overall size of the window.

6. Use a template for complex shapes: For windows with highly irregular shapes, you can create a template by tracing the outline onto a piece of paper or cardboard. This template can then be used to measure the perimeter of the window.

Shape	Measurement Method
Arch	Use a template to measure the perimeter.
Triangle	Measure the base and height of each triangle and add them together.
Circle	Measure the diameter and multiply it by π (3.14).
Semicircle	Measure the diameter and multiply it by π (3.14) and divide by 2.

Using a Laser Distance Measurer for Accurate Measurements

Laser distance measurers offer precise and efficient measurements for windows and other home improvement projects. Here’s how to use one for accurate results:

1. Calibrate the Laser

Before using, calibrate the laser to ensure accuracy. Measure a known distance and adjust the device as needed.

2. Position the Laser

Hold the laser perpendicular to the window surface and aim the beam at the desired point.

3. Determine the Measuring Point

Decide whether you need to measure from the inside or outside edge of the window frame or glass.

4. Measure the Width

Start measuring from one side of the window opening to the other, perpendicular to the frame.

5. Measure the Height

Measure from the top to the bottom of the window opening, parallel to the frame’s vertical edge.

6. Measure the Diagonal

Measure the distance from one corner of the window to the opposite corner to verify squareness.

7. Calculate Additional Measurements

In addition to width, height, and diagonal, you may need to calculate additional measurements, such as:

Window Frame Width: Measure from the outside edge of one frame to the outside edge of the other.
Window Frame Length: Measure from the top edge of the frame to the bottom edge.
Window Glass Width: Measure from the inside edge of one glass pane to the inside edge of the other.
Window Glass Height: Measure from the top edge of the glass pane to the bottom edge.

Measuring Window Height

To measure the height of a window, start at the top of the frame and measure down to the bottom of the frame. Make sure to include the entire frame, including any trim or molding. If the window has a sill, measure from the top of the sill to the bottom of the frame.

Measuring Window Width

To measure the width of a window, start at one side of the frame and measure across to the other side of the frame. Make sure to include the entire frame, including any trim or molding. If the window has a casing, measure from the outside edge of the casing on one side to the outside edge of the casing on the other side.

Measuring the diagonal

For odd-shaped windows like arched or triangular windows, the diagonal measurement provides a good reference. Take a measurement from the upper left-hand corner diagonally to the bottom right-hand corner. Measure in inches with a measuring tape. Round the number to the nearest inch.

Measuring Special Shapes

For special shapes, like circles or ovals, you’ll need to measure the height and width of the largest rectangle that can fit inside the shape. You can also measure the diameter of the circle or oval.

Troubleshooting Common Measuring Mistakes

Mistake 1: Using the wrong tool

The best tool for measuring windows is a steel tape measure with a hook on the end. Avoid using a cloth tape measure or a ruler, as they can stretch or break easily.

Mistake 2: Not accounting for trim or molding

When measuring the width and height of a window, be sure to include the entire frame, including any trim or molding. This will ensure that your window treatments fit properly.

Mistake 3: Measuring the outside of the frame

When measuring the width of a window, be sure to measure from the inside of the frame, not the outside. This will ensure that your window treatments fit properly.

Mistake 4: Measuring the wrong type of window

There are different types of windows, such as casement windows, double-hung windows, and awning windows. Be sure to measure the correct type of window for your needs.

Mistake 5: Making a mistake in the calculation

When calculating the size of your window treatments, be sure to double-check your measurements to avoid any mistakes.

Mistake 6: Adding too much length

When hanging curtains or drapes, it’s important to add only a little bit of length to the measurements. Adding too much length can make your window treatments look sloppy and unprofessional.

Mistake 7: Not allowing for overlap

When hanging blinds or shades, it’s important to allow for some overlap between the panels. Not allowing enough overlap can cause gaps in your window treatments, which can let light and heat into your home.

Mistake 8: Measuring the wrong area

Make sure to measure the area where you plan to hang your window treatments. This may not always be the same as the size of the window frame. For example, if you plan to hang curtains outside the window frame, you will need to measure the distance from the ceiling to the floor and from the outside edge of one wall to the outside edge of the other wall.

Tips for Measuring Windows for Installation

Step 1: Identify the Type of Window

Determine whether your windows are single-hung, double-hung, casement, or sliding.

Step 2: Gather the Necessary Tools

You will need a measuring tape, a pencil, and a notebook.

Step 3: Measure the Width

For single-hung and double-hung windows, measure the width from the outside edges of the frame.

Step 4: Measure the Height

For single-hung windows, measure from the top of the top sash to the bottom of the bottom sash. For double-hung windows, measure from the top of the top rail to the bottom of the bottom rail.

Step 5: Measure the Depth

Measure from the outside edge of the frame to the inside edge of the frame.

Step 6: Measure the Jamb

Measure the width of the vertical sides of the frame (left jamb and right jamb).

Step 7: Measure the Sill

Measure the width of the bottom horizontal part of the frame (sill).

Step 8: Measure the Head

Measure the width of the top horizontal part of the frame (head).

Step 9: Measure the Rough Opening (Advanced)

Measure the width and height of the opening in the wall where the window will be installed. This is typically required for new construction or replacement windows.

Window Type	Width Measurement	Height Measurement
Single-Hung	Outside frame edges	Top of top sash to bottom of bottom sash
Double-Hung	Outside frame edges	Top of top rail to bottom of bottom rail
Casement	Outside frame edges	Top of top rail to bottom of bottom rail
Sliding	Inside frame edges	Top of top rail to bottom of bottom rail

Safety Considerations When Measuring Windows

1. Wear Appropriate Clothing and Safety Gear

Long sleeves, gloves, and safety glasses can protect you from potential hazards like glass shards or splinters. Wear sturdy, closed-toe shoes with non-slip soles to prevent slips and falls.

2. Check for Electrical Hazards

Before measuring windows near electrical outlets or wiring, turn off power at the circuit breaker or fuse box. Use a non-contact voltage detector to confirm that there is no electrical current present.

3. Use a Ladder Carefully

If you need to use a ladder to measure high windows, place it on a level and stable surface. Never stand on the top step of the ladder, and have someone hold the base for stability.

4. Be Aware of Your Surroundings

Pay attention to your environment while measuring windows. Avoid tripping over obstacles or bumping into furniture. Be cautious of any potential falling objects or hazards.

5. Measure Accurately

Take precise measurements to ensure proper fit for window treatments or replacements. Use a high-quality measuring tape or laser measure for accuracy.

6. Consider Window Style

Different window styles have specific measurement requirements. Measure the width, height, and depth of the window frame to determine the correct dimensions for curtains, blinds, or other coverings.

7. Allow for Overhang or Insert

When measuring for window treatments, consider the desired overhang or insert. Allow for extra fabric or material to cover the window frame and provide ample coverage.

8. Inspect for Obstructions

Check for any obstructions inside or outside the window frame that may interfere with measurements or window coverings. These include window cranks, locks, or architectural details.

9. Document Your Measurements

Keep a record of your measurements for future reference. Note the type of window, dimensions, and any special requirements or considerations.

10. Seek Professional Help if Needed

If you encounter any difficulties measuring your windows or have complex window configurations, consider consulting a professional window installer or designer for assistance. They can provide accurate measurements and ensure proper installation of window coverings or replacements.

Safety Gear	Purpose
Long sleeves	Protect from glass shards
Gloves	Protect hands from splinters
Safety glasses	Protect eyes from flying debris
Sturdy shoes	Prevent slips and falls
Non-contact voltage detector	Detect electrical hazards

How to Measure Windows

Measuring windows correctly is essential for ensuring that replacement windows fit properly and function efficiently. Here’s a step-by-step guide on how to measure windows:

1. **Determine the Type of Window:** Identify whether your window is a single-hung, double-hung, sliding, or casement window.

2. **Measure the Width:** Measure the width of the window frame from side to side. Take the measurement at the widest point, including the trim.

3. **Measure the Height:** Measure the height of the window frame from top to bottom. Include the trim in your measurement.

4. **Measure the Sash:** If you have a single-hung or double-hung window, measure the height and width of the sash (the part that moves up and down).

5. **Measure the Jamb Depth:** Measure the depth of the window frame from the inside edge to the outside edge. This determines the thickness of the window.