GroWrk uses a weighted sum derived from the papers referenced here , which determine a 12.62% average productivity increase for furniture with training (compounded) and 35.5% for an extra screen. According to the products selected, the yearly cost is calculated and only the productivity weights from those products considered. The equation assumes a five day workweek. Breakeven is given as how many days per month it requires for the monthly cost to pay itself.

Total productivity increase per year is calculated by adding the yearly productivity increase rates of the selected products. Productivity increase per day is obtained by multiplying the yearly salary by the productivity increase per year, then dividing by the number of workdays in a year. Days needed for breakeven of the monthly cost are calculated by dividing the total cost of the selected products per year by the productivity increase per day, then dividing by 12 to make it per month.

K

0.0631
N

0.355
R

0.0631
P

K + N + R
D

S + P / 240
B

B= C / D / 12
B

Days per month for breakeven

C

Cost per year

S

Salary per year

D

Productivity increase per day

K

Desk productivity increase per year

N

Screen productivity increase per year

R

Chair productivity increase per year

P

Productivity weights from selected products per year