How will my 50% twelfth score impact my chances of getting admitted to Irish universities, given my 68% in postgraduate Computer Science and 12 years of work experience?

It depends on the specific program, but your Class XII score is unlikely to be the deciding factor for postgraduate admission in Ireland, since universities primarily evaluate your bachelor's and postgraduate academic record for master's-level applications.

How Irish Universities Weigh Each Qualification

What Universities Actually Publish

• University of Galway: India-specific postgraduate equivalencies of 55% for a 2:2 and 65% for a 2:1, applied to bachelor's or relevant postgraduate qualifications, not Class XII.
• Trinity College Dublin: MSc Computer Science programs typically require a 2:1-equivalent degree in Computing or a related discipline.
• Maynooth University: Its MSc Computer Science (Applied) allows a Recognition of Prior Learning route for applicants without a primary degree who have at least 3 years of relevant experience.

My Advice

Share your bachelor's degree and percentage along with your postgraduate CS qualification with each university's admissions team directly, since a hard academic minimum can still apply regardless of your 12 years of experience. If your bachelor's score is also on the lower side, look specifically at programs like Maynooth's Recognition of Prior Learning route that are designed for experienced professionals.