Nobody knows. It seems to chop and change with the wind. I’m sure when he first came in there was a big age gap between him and Moira. When she left home at 18 he was meant to be a small child. So much so that I remember initially there were rumours that she was really his mum. Then somewhere down the line he was only a few years younger than her, approximately in his early 40s now. He must be about that or nearly mid-40s as he’s meant to be old enough to remember the 80s TV series The A Team as he’s supposedly a big fan. The actor however is only early 30s
Edit: According to Fandom, Mackenzie was born c1983 so is about 40. I’m sure when I’ve looked before there wasn’t a year there. The fact it says ‘circa’ 1983 means they don’t really know and are just guessing as well. The actor was born in November 1991 so is 32 in real life
Mackenzie "Mack" Boyd is the long-lost younger brother of Moira Dingle, the father of Reuben Harris, and the husband of Charity Dingle. Mackenzie was the second child of Ann Boyd and her husband, after Moira. Mackenzie was about twelve years Moira's junior. Mackenzie's childhood was marred by...
emmerdale.fandom.com