I am trying to burn the little fat I have left on my body so that my abs start to show but theres not a lot of fat there and somebody told me I should be doing 30 minutes of cardio i.e running/ jogging and then 30 minutes of crunches, pushups, dumbells, etc... but I'm wondering is 30 minutes a day enough if not how much cardio should I be doing to burn the fat? also 3 days out of the week I do HIIT training

Depends. What type of cardio training are you doing in that 30 minutes?
Also, strength training as you mentioned is also very important in burning excess fat, so remember don't be primarily concerned with just the cardio side of things.
Not to mention, losing that last bit of fat to become toned as such can often be the most difficult, you should have a very healthy diet plan.

I used to do cardio for around 20 -25 mins, and i don't had put on any weight..
So it's quite sufficient for me.

When you lose more fat do you have abs to show? I'd highly suggest you do intervals for cardio and get on a good full body weight routine.

When you say "little" what are we talking about? What is your body fat percentage? Are you a male or a female?

Trying to cut beyond 3-4% for a guy (im guess you're a guy by the name) requires serious training and diet and is unsustainable for more than a few weeks. Bodybuilders only get that rigorous for competitions. Depending on what your actual goal is, you might have unrealistic expectations.

Either way, it is going to take a combination of cardio, weight lifting, super-clean eating, supplements, and even flexibility training to reduce body fat. Beyond a certain point, though, the sacrifice and requirements in each of those areas becomes drastic, so you might need to reconsider your goal here.

Are you a competitor or just want to show off at the beach?

I think it requires the person to be deceased first

I typically find myself doing 45-60 minutes of cardio 4-5 times a week, but I doubt that this amount is truly necessary. I've done 30 minutes a day for 4-5 days a week before and it worked fine. But I monitored my sugar and carb intake too.

Significant benefits can be had from 20 mnutes of cardio or even 10 minutes of HIIT or as little as 4 minutes of Tabata HIIT. If you are already doing HIIT 3 timea a week no additional cardio is needed, but you might want to do 2 days of HIIT a week and one day of steady state cardio. Remember the main advantage of exercise is not how long you do it or how many calories you burn while doing it, but the elevated number of calories you burn after the exercise session is over, due to increased metabolism and energy required for recovery, sometimes called EPOC (exercise post oxygen consumption).

as I stated above I do interval training 3 days out of the week

30 min. of running / day has been great for me.. I am down 40 lbs and counting!

-Chris

Get another persons advice.

This makes the assumption that cardiovascular (aerobic) activity (for you) is necessary in the first place, when considering just your goal want, and not endurance improvements and other aspects of your goal desires.

Cardio, can be a miss used term, and abused. It seems some believe that aerobic activity (aka, cardio), is some type of magic fat loss exercise, and this is simply not the case.

It can be a piece in the personal puzzle (dependent), but, as far as I'm concerned, spending hour after hour on the treadmill (or other machine) is all but worthless if the remaining pieces of the puzzle aren't in place: Setting up your dietary perimeters, other aspects of training, and making adjustments as you move forward.


What is your height, weight, gender, and age? What do you have to train with? A gym or at home?

Open up with information about yourself.



I will check this thread from time to time, to see if you posted and/or answered questions.

Peace be with you and success.

Chillen

30 minutes of HIIT for the Intermediate to Advanced is definately acceptable, as long as it is accompanied by a good diet and clean eating.