Pin It

How to Calculate Scale

When it comes to interior decoration and other forms of design, it takes more than just an instinct for style to transform a room! Designers and decorators must also learn how to calculate scale, so they can create a floor plan. This ensures that the design they have in mind will work well with the physical layout of the room and the space that they have available. Professionals who master the art of calculating scale will save time and effort, letting them concentrate on things like the atmosphere they’d like to achieve with their décor, rather than shifting heavy furniture that doesn’t fit the way they’d hoped!

Calculating the size of a room and converting it on a scale to make your floor plan takes practice. Once you’ve become familiar with this skill, however, you’ll find that it’s one of your most useful tools for every room you design! Not only does using a floor plan to scale help you with your design itself, it also helps you communicate your ideas to clients or team members in a way that lets them visualize your ideas! Here are some tips for both calculating scale and translating from one scale to another to complete your design!

What is a Floor Plan and why is Scale Important?

Floor Plan

A floor plan is an aerial drawing of the room you’re working with. Instead of trying to think about your design in large, real-life proportions, you’ll draw a smaller representation of your room so that you can visualize your plan more clearly. If you simply draw a rough sketch of the room, however, you’ll find that your measurements will be off when you try to translate that floor plan back to the real thing. Furniture and wall hangings might not fit in the spaces you want them to, and you’ll have to re-evaluate.

This is where calculating scale saves the day! By taking real measurements of the room and scaling them down so that they’re small enough to draw but are still proportional, you can create an accurate floor plan to create your design on. This way, when you translate the scale back into real-life measurements, your spacing should work!

Measuring Your Space

The first step to creating an accurate scale is taking measurements of the room. When you do this, make sure that you take your measurements in feet and inches, as this is the standard that most professional designers and decorators use. Remember to round all of your measurements up to the nearest inch. Rounding makes your scale much easier to calculate and translate. Measuring up saves you from realizing later that your furniture or wall hangings barely fit! For example, the height of a wall from floor to ceiling might be 7 feet and 7 ¾ inches, which you would write as 7’8”.


Here are some key things to measure:

Floor Space:

Measure the lengths along the floor where it meets each wall. This gives you the general size of the room.


Measure the height and length of each wall so you can draw the shape of the room in the correct proportions on your floor plan, to scale.


Make sure you take note of where the windows are. Not only will you need these measurements if your design includes things like curtains, but you’ll also want to make sure none of the furniture you place blocks the window!


Like windows, you’ll want to note the size and placement of your doors. This way, you can draw them to proper scale. First, measure the size of the door opening so you can make sure none of the furniture in your plan will block people from getting into the room. Next, if there is one, measure the door itself. If it’s the kind of door that swings into the room, note how far into your space it goes so that you don’t place anything where the door will hit it or be stopped from opening.

Other Features:

Take note of the size and placement of key features throughout the room. Remember that you’ll need to leave space for these or leave them accessible when you’re planning your furniture. Look for the following things:

  1. Floor vents
  2. Radiators or heaters
  3. Electrical outlets and telephone jacks
  4. Fireplaces
  5. Raised platforms/areas


Calculating Your Scale

Drawing a Floor Plan

The easiest way to draw measurements to scale on a page is by using 1 inch (1”) to represent 1 foot (1’). This means that, in your floor plan, a table that is 3 feet by 2 foot (3’ x 2’) would be drawn as 3 inches by 2 inch (3” x 2”). It helps to translate your scale using a ratio.

Take our scale of 1” = 1’, for example. There are 12 inches in a foot, so you would write your ratio as 1:12. 1 inch on your page represents 12 inches in real life (or 1 foot).

Graph Paper

Some designers choose to use scaled graph paper to create floor plans. This makes calculating your scale very easy, because each square on the paper can represent one foot. To draw your 3’ x 2’ table, you would simply count 3 squares across and 2 squares deep. As long as you are consistent with keeping to that scale, your floor plan should translate well to your actual space.

Try it out!

By scaling down measurements like this, you are able to organize a plan for the room that works well in the space. Staying consistent with you scale means that your measurements stay properly proportioned and can translate back into the real life space. Scaling lets you try different furniture and decorative options within the space without the ordeal of moving the furniture repeatedly!

Scaling is easy to practice! Grab some graph paper and try drawing a floor plan for the room you’re in!

For more helpful information about skills like calculating scale, check out QC’s Online Design Courses!