100% Percent Learnable – Percentages & How To Use Them
Numbers 18 years ago No Comments


Working with and interpreting percentages tend to cause otherwise intelligent people to get a little loopy. According to Steve Slavin’s book, All The Math You’ll Ever Need, “perhaps nine out of ten college graduates can’t work out percentage changes.” And he’s not just talking about people with artistic bents – he’s talking about everybody. So we’re here to help, applying the technique to situations relating to the world of design, of course. Go forth and learn something, and we won’t tell anyone you read this – we promise.

In our last installment, we talked about fractions as percentages and percentages as fractions. We showed you how to convert back and forth easily because… what is a percentage, really” It’s simply a fraction of 100.
See, it’s all the same thing.

Now it’s time to talk about using percents and figuring out percent changes. Empowering yourself with this knowledge will allow you to make critical everyday calculations, figuring out important stuff you need to know like…

  • how much more marble tile to order in order to accommodate breakage and pattern waste;
  • how many more people to plan for according to your corporate client’s long-range growth projections;
  • and what it really means when the boss says she’s going to give you a 5% raise.

Example No. 1

When ordering materials – whether it be carpet, fabric, wallcovering, plastic laminate, paint, tile, etc. – it’s common to order a little more than you absolutely need because…

  • initial estimates can be off (that’s why they’re called estimates)
  • materials can be damaged and broken in shipping
  • a certain amount of waste (i.e. material that cannot be used because it has to sacrificed to achieve a specific, desired result) will exist due to the pattern on the product and/or the method of installation you have specified

Let’s say you are a decorator, and your client is dead-set on a particular hard-to-get tumbled marble tile from Italy to use in their courtyard. While traveling in Venice, they fell in love with a certain pattern in an old villa and took a picture to show you. The layout is quite intricate, but it’s what they want, and they are willing to pay for it.

After calculating the initial materials estimate and researching the manufacturer’s point of origin, as well as the sales and shipping requirements, you know the project will require a minimum of 48 boxes of tile. Normally the waste factor you would build into the order would be 10%…
However, you are privy to the following information:

  • This Italian manufacturer takes a long time to ship their product.
  • The manufacturer is about to close down their operations for three weeks so that its workers can go on holiday.
  • Your client is adamant is adamant about having the patio completed by a specific date.
  • The tile installer your client insists on using was extremely sloppy on the last job, requiring you to order more materials.
  • Your client keeps hinting around that they might be interested in having a tabletop made out of this tile as well.

In light of the circumstances, you know that it would be safer to order 65 boxes. What new waste factor will you be building in”
This new waste factor is 3-1/2 times more than you were originally going to use [35% ÷ 10% = 3.5], but you know that it will keep you, your clients, and the tile installer happy. And who says you can’t buy happiness”

Example No. 2

Your client, Widgets Limited, anticipates staffing their current employee base of 235 up approximately 15% over the next year. They need you, as a space planner, to develop some options on how to best reconfigure the open office workstation layout. How many more people do you need to be able to accommodate”
However, after playing around with the space plans, you realize that they could actually accommodate up to 287 people if they needed to do so. You want to tell them the good news in a percentage number because that’s how companies love to communicate.
To really geek out and show your fantastic space planning skills, you want to let them know what percentage more you were able to accommodate (52 people) than they originally asked for (35 people).
Now you sound like a space planning genius, and they will surely love you.

Example No. 3

You’ve worked for your current job as a sales representative in a high-end lighting showroom for one year. Since you’ve been performing your magic with your interior design clients, their sales volume has increased from $225,000 to $260,000. What percentage did it increase over the year”
When you go tell your boss, the showroom manager, that your stellar performance has earned you a raise, she says that she can afford to give you a raise of 5% per annum. So what will you soon make per year if you are currently making $33,500″
Tip: A faster way to do that is…
You feel like you should be earning at least $36,000 for all of the hard work and overtime you put in, so you want to propose a new raise percentage. What would that be”
Now whether or not you get that raise is an entirely different topic…

Take Heed

Fear not the percentage, for it can work for you if you understand it – but against you if you do not!