Numbers seeking function

April 13, 2024 7:02 PM

For some of my smaller spaces I want to offer design by the square metre and enable my clients to work out my fee*, which will hopefully help them to pick up the phone. The aim is to present people with a simple function so they can do it themselves, e.g. if they've got say 225 square metres what will that cost them? I'm hoping to find something people as non-numeric as myself can punch into a calculator: area operation number operation number = $number

For the smallest area of 100m² that $2717 would work for me (17 hours @ $160 an hour) [ and maybe a bit less than that say as low as 14 hours], and for 300m² (the largest area) fee would be $3680 (23 hours @ $160 an hour). But those numbers are artificial (from experimenting with Excel solver to arrive at acceptable sums) and I can't get them with the same function, I don't think the answer is linear.

I do want them to be aable to enter a measure area, I'm not looking for a tiered fee structure.

*I've asked about this on ask me years ago but I now need something quite different, as my upper and lower bounds are not calculated, they are simply what I feel are acceptable charges for the work.

posted by unearthed to Work & Money (4 answers total)

It sounds like you might want a flat fee plus an amount per square metre, which based on your two data points, would be $2240 plus $4.80 per square metre, which works out to $2720 for 100m2 and $3680 for 300m2. It might be simpler to round those numbers to $2200 and $5 per square meter, which gives $2700 and $3700. You could equivalently express that as $2700 for the first 100m2 and $5 per additional square metre, if that feels better.
posted by ssg at 7:34 PM on April 13 [7 favorites]

Best answer: Seems like your minimum fee is $2717 and after that it's an additional ~$4.85 for every square meter over 100?

So for 100m²: 2717 + 0 * 4.85 = 2717

For 300m²: 2717 + 200 * 4.85 = 3687

For 200m²: 2717 + 100 * 4.85 = 3202

So the equation/thing to type into the calculator would be:

((Area - 100) * 4.85) + 2717
posted by mskyle at 7:35 PM on April 13 [1 favorite]

Given your numbers, and a desire to make it easy, I like the round numbers suggested by ssg:

$2200 + $5 * (area in m²)

This works out as::

100 m² : $2200 + $5 * 100 = $2700
200 m² : $2200 + $5 * 200 = $3200
300 m² : $2200 + $5 * 300 = $3700

posted by RichardP at 7:46 PM on April 13 [4 favorites]

Response by poster: Thanks ssg and RichardP for thinking about a solution, and to mskyle for the exact thing.

My question form is now:

Your area in m² minus 100, x that by 4.85, and add 2717
posted by unearthed at 6:42 PM on April 16