To do these conversions, you'd need a solid understanding of what each YOE entails, and there is no good or widely accepted definition on that, otherwise it would be the hiring standard and career path standard.
I only say this because you can't literally put down that you gained 6 YOE on your resume - you will instead convert it to milestones and accomplishments and deliverables, all of which are completely understandable concepts and better suited to get your point across.
Time to drop this flawed thinking IMO