It's difficult to quantify the intangible benefits, so I would recommend that you begin by quantifying the financials and then determine whether the difference between the pay of the two jobs justifies the value of the intangible benefits to you.
You are making $55,000 per year, but your employer is also paying for a number of benefits that do not come free as a contractor. Begin by writing down everything they are providing you that you would like to continue to have. This may include:
- health insurance
- life insurance
- dental insurance
- legal consultation
- 401k matching or retirement contributions
- stock options
- and more
You also need to account for the FICA tax that you need to pay completely as a part time employee (normally a company pays half of it for you). This usually amounts to 7.8% of your income.
Start by researching the cost for providing each item in the list above to yourself. For health insurance get quotes from providers. For bonuses average your yearly bonuses for your work history with the company. Items like stock options you need to make your best guess on.
Now lets call your original salary S. Add up all of the costs of the list items mentioned above and call them B. This formula will tell you your real current annual compensation (RAC):
Now you want to break your part time job into hours per year, not hours per month, as months have differing numbers of working days. Assuming no vacations that is 52 weeks per year multiplied by 20 hours, or 1040 hours (780 if working 15 hours per week). So to earn the same at the new job as the old you would need to earn an hourly wage of:
- HW = RAC / (Working Weeks * Hours Per Week)
- HW = RAC / 1040
- HW = RAC / 780
The full equation for 20 hours per week works out to be:
- HW = ((S * 1.078) + B) / 1040
DO NOT TAKE THIS SECTION AS REPRESENTATIVE OF YOUR SITUATION; ONLY A BALLPARK ESTIMATE
You must do the math yourself. I recommend a little spreadsheet to simplify things and play what-if scenarios. However, we can ballpark your situation and show how the math works with a few assumptions.
When I got quoted for health insurance for myself and my partner it was $700 per month, or $8400 per year. If we assume the same for you, then add 3% 401k matching that we'll assume you're taking advantage of ($1650), the equation becomes:
- HW = ((55000 * 1.078) + 10050) / 1040
- HW = (59290 + 10050) / 1040
- HW = 69340 / 1040
- HW = $66.67
Keep in mind that there are other considerations that could offset these calculations. Variable hours are a big risk, as is your status as a 'temporary' employee. Though on the flip side you don't need to pay taxes out of each check, allowing you to invest that money throughout the year until taxes are due. Also, if you are considered a private contractor you can write off many expenses that you cannot as a full time employee.