How to Measure a Wall for Wallpaper

Accurate measurements are the foundation of every successful wallpaper project. Measure incorrectly and you will either order too little wallpaper — risking a dye lot mismatch if you need to reorder — or too much, wasting money on rolls you do not need. This guide walks you through the exact process professionals use to measure any room.

What You Will Need

• A retractable steel tape measure (at least 5 metres long)
• A pencil and notepad, or your phone for notes
• A step ladder for measuring ceiling height accurately
• A helper (optional but useful for long walls)

Avoid using fabric or sewing tape measures — they can stretch and give inaccurate readings. A steel or fibreglass tape measure is essential.

Step 1: Sketch Your Room

Before pulling out the tape measure, draw a rough sketch of the room on paper. It does not need to be to scale — just a bird's-eye view showing all four walls, with boxes for doors and windows. You will write your measurements directly on this sketch, which prevents the common mistake of mixing up which measurement belongs to which wall.

Label each wall (A, B, C, D or North, South, East, West) and note which wall has the main entrance, which has windows, and which walls you plan to wallpaper. If you are only doing an accent wall, you still want to sketch the full room to give context.

Step 2: Measure the Ceiling Height

Measure from the floor to the ceiling at multiple points along each wall. In older homes especially, ceiling height can vary by 1-2 cm from one side of a wall to the other. Always use the tallest measurement for cutting your strips — you can trim excess but you cannot add length.

If you have crown moulding and plan to wallpaper below it (the most common approach), measure from the top of the baseboard to the bottom of the crown moulding instead.

Important: Measure the height at the left edge, centre, and right edge of every wall you plan to wallpaper. Record the largest of the three. In some homes the difference can be as much as 3-4 cm, especially in older construction or basement rooms with slightly uneven floors.

Step 3: Measure Wall Widths

Measure the full width of each wall from corner to corner. Run the tape measure along the wall at about waist height — not along the baseboard, which may not follow the wall exactly, especially if it was replaced or shifted.

For a full-room installation, you can simply measure the room perimeter. Run the tape measure around the room at a consistent height, pulling it taut. Record this as a single number. If the room is rectangular, you can also measure two adjacent walls and double the total: perimeter = 2 x (length + width).

Step 4: Measure Doors and Windows

For each door and window on the walls you plan to wallpaper, measure:

• Width: Measure the width of the opening including the frame (casing). This is the area where you will not need wallpaper.
• Height: Measure from the floor to the top of the door frame, or from the bottom of the window sill to the top of the window frame.
• Position: Note how far the door or window is from the nearest corner. This helps plan where your strips will fall and where you will need to cut around the opening.

Standard Sizes for Reference

If you cannot measure directly (for example, you are ordering wallpaper before moving in), these standard dimensions can serve as estimates:

• Standard interior door: 80 cm wide x 200 cm tall (frame adds about 8 cm to each dimension)
• Standard window: 120 cm wide x 120 cm tall
• Patio or sliding door: 180 cm wide x 210 cm tall

However, always measure if you can. Actual dimensions vary widely, especially in homes built before standardised building codes.

Step 5: Note Obstacles and Features

Mark the following on your sketch and measure their positions:

• Electrical outlets and light switches: You will cut around these, but they do not reduce your wallpaper quantity — the strip still needs to span the full width.
• Radiators and heaters: Measure the width and how far they project from the wall. You typically wallpaper behind radiators, but only about 15-20 cm down, tucking the paper behind where visible.
• Built-in shelving or cabinets: Decide whether you will wallpaper behind them or treat them as deductions.
• Fireplaces and mantels: Measure the width and height of the fireplace surround and its position on the wall.

Step 6: Calculate Total Wall Area

Once you have all measurements recorded, the calculation is straightforward:

1. Gross wall area = Total wall width (or perimeter) x ceiling height
2. Deductions = Sum of (width x height) for each door and window
3. Net wall area = Gross area minus deductions

Take your net wall area and plug it into our wallpaper calculator along with the roll size and pattern repeat of your chosen wallpaper. The calculator handles the roll quantity math including waste factor.

Common Measuring Mistakes

• Measuring only once. Always measure each dimension at least twice. Misreading the tape measure by even 5 cm on wall height can mean ordering too few strips per roll.
• Ignoring ceiling height variation. A wall that is 244 cm on the left and 247 cm on the right must be cut at 247 cm. Those 3 cm matter when you are calculating how many strips fit on a roll.
• Deducting too much for windows. A common instinct is to subtract the entire wall section that contains a window. But you still need wallpaper above and below the window, and the strips beside the window often cannot be cut from the same piece. Only deduct the actual window opening area.
• Forgetting about recesses. Window reveals (the depth of a recessed window) need wallpaper too. If your window is recessed 20 cm into the wall, you need to account for wallpapering the top and sides of the reveal.
• Rounding down. Always round up when converting measurements to rolls. A calculation that says 5.1 rolls means you need 6 rolls, not 5.

Measuring an Accent Wall

For a single accent wall, the measurement process is simpler but the same principles apply:

1. Measure the wall width at the widest point.
2. Measure the height at the tallest point (check both edges and centre).
3. Deduct any doors or windows on that wall.
4. Calculate the number of strips: wall width divided by wallpaper roll width, rounded up.

For an accent wall, centering the pattern is important for visual balance. Divide the wall width by the pattern width to determine how many full pattern repeats will fit. If it is not a whole number, you will want the partial patterns on each edge to be equal.

Measuring Rooms with Angled or Sloped Walls

Attic rooms, rooms under stairs, and rooms with cathedral ceilings have varying wall heights. For these:

• Measure the wall height at every 50 cm interval across the wall. Record each measurement.
• Each strip will be a different length. Cut each strip individually rather than batch-cutting.
• Use the tallest measurement when calculating how many strips per roll, since the longest strips dictate roll usage.

Recording and Sharing Your Measurements

Write your measurements in centimetres or metres — avoid mixing metric and imperial. If you are sharing measurements with us for a quote or recommendation, include:

• A labelled sketch or photo of the room
• Ceiling height (the tallest measurement)
• Width of each wall being wallpapered
• Dimensions and position of each door and window
• Any notes about wall condition or obstacles

With accurate measurements in hand, use our wallpaper calculator to determine exactly how many rolls to order. Then head to our complete hanging guide to learn the installation process step by step.