Easy answer. No such thing as the "going rate"
Hard answer; do the math. Billable Rate = total cost to do business + profit margin. Add up all your costs. Then add in your profit margin. Don’t leave anything out including your time spent preparing invoices and other administrative duties, all insurances, all taxes including payroll, CUTA, SUTA, FUTA property, sales, etc, hotels, on road meals, fuel, oil, tires, equipment depreciation, tool/test equipment repair/replacement. Professional services such as CPA, legal, banking, etc. And the list goes on. Only you know all your costs.
Best advice; You don’t want to get paid the “going rate" if contractors are going broke on the "going rate"