The estimated average salary for a Senior Process Development Engineer at Merck is €70,000 per year or €34 per hour, but some professionals have reported earning up to roughly €83,600 per year (90th percentile). The typical pay range is between €57,005 (25th percentile) and €79,000 (75th percentile) annually. This is based on 8 salaries submitted by Merck Senior Process Development Engineer professionals on Glassdoor, as of Jul 2026.