How old are the Mane 6 now?

[DivineDefender1000 71,372]

I honestly don’t know. I’d their st least in their 20s or maybe they’re teenagers now.

Can anyone help me out with this?

[Kevin Tang 2,426]

Maybe around almost 30 years old?

[O-78 28,607]

I imagine they'd all be in their early 20s.

[AveryGamerDude 4,640]

I think Baby Cakes are still babies, so I think they're the exact same age as they were since the beginning.

[Once In A Blue Moon 895]

The guess I would make is largely centred on Twilight; if leaving Canterlot and defeating Nightmare Moon was graduation that would put her in the 20 to 23 age range. Becoming an alicorn princess would be her PhD in Friendship, so at least another 3 - 4 years. Starlight's graduation would be another 2-3 years after that, so my entirely arbitrary estimates put her at anything from 25 to 30 as of the start of season 7.

The rest I would guess to be roughly similar, based on the events shown in The Cutie Mark Chronicles - I think Applejack is a bit older, as she mentioned being the last to get her cutie mark, plus she was leaving home to live with her aunt and uncle at the time while we know that Fluttershy is older than Pinkie (albeit not by much) and she does look longer in the leg than Rainbow Dash.

Based on that, I'd put them in order, from oldest to youngest:
1. Applejack

2. Fluttershy

3. Pinkie

4. Twilight

5. Rarity

6. Rainbow Dash

Again, rather arbitrarily - I'm working on the assumption that the brasher Rainbow Dash might be a bit younger and Rarity was working on a quite junior-looking school play, leaving Pinkie and Twilight somewhere in the middle.

Edited February 9, 2019 by Once In A Blue Moon

[PoisonClaw 8,164]

When the show started they were all old enough to hold down jobs and live on their own, which would put them at around 18-22 or so. Assuming that around 6-7 years have gone by (maybe even more with how many episodes lately have been during the winter), I would say the Mane 6 would be somewhere around their mid to late 20s by now.

[Steve Piranha 29,428]

It has been implied that a single year passed between S1 and S4 premiere, however, we had at least one Hearts Warming celebration per season starting with the fifth (the eight had two HW, an episode, and the post season special, filling the quota with the otherwise absence in S7), so it could be safe to say that a year passed per season most of the time. 

IDW released a series of comics with many of their licensed series, with most of them taking place 20 years in the future. Ponies did the opposite, so it’s likely they are at least in their mid 20s by now 

Edited February 9, 2019 by Steve Piranha

[Cash In 22,445]

I want to say that they were around the ages of 18 to 19, in human years at the time of Season 1. As of the end of Season 8, I would say that they're three to four years older.

[Flutterstep 47,100]

They’re cartoon aged. One minute Twilight is helping run the country, the next she’s having a sleepover. There’s not really a defined age for the Mane 6.

[Senko 459]

I'd put them in their mid 20's myself with them starting at early 20's/late teens in season 1. I'm currently working on a timeline for the show and season 1-4 is pretty much one and a half years (explains their breakdowns) and then it slowly expands as things calm down and more time passes between them. I'm happy to post what I have here and the full thing when I'm done (working through season 6 currently but real life is keeping me busy). However as of the end of season 5 I'm looking at around 4 years worth of time having passed.

[EpicEnergy 23,222]

I don't really pay attention to that as it can be rather confusing, but I suppose their are around their 20's.