You will be in ketosis at under 50g carb per day. There have been days that I have not particularly limited my carb intake, and ended up in the ketosis range, as long as I didn't each much fruit. I have now added a bit more fruit and a starchy veg or rice and I am only at 70-80g carbs, just because I don't eat tons in general now. I would say it is easy to dip into the ketosis range without even trying to for some of us.
As a sidenote, my stalled weightloss started up again since I added more carbs.