How much grafts I need to cover this area? (Photo)

There are a couple of variables at play here - your hair density, follicular diameter and natural scatter, for example.  In your case, a rough estimate would be between 1500 and as many as 2000.  But you could go down to 1250 or so depending on natural density, etc.  The range can be quite wide, and a good physical exam should be able to give your doc an idea after measurements.

Hair transplant surgery is not always about "how many grafts" you need.  What happens if you continue to lose more hair behind the hair line?

Thanks for your photo and based on it you will need around 2000-2300 grafts to reconstruct the frontal part which means filling in the temples and lowering your hair line a bit. This amount will help to achieve a natural and good result with high density.

You desire a low and broad hairline. You may regret this one day if you continue to loose hair.  I would not recommend this hairline for you because it is aggressive. Filling this area in will require at least 1500 grafts and perhaps more. You have thinning in the areas you still have hair so these thin areas will need grafts. The degree of thinning could push you to 2000 grafts. A higher hairline is much safer and requires fewer grafts. You may also desire a second pass for fullness. Some people get three passes of grafts. 

Thanks for submitting the photograph. Often it is easier to tell what you need in person, but a rough estimate from what I see is in the range of 1200-1500. Hope that helps.

With the line that you have drawn in you are actually lowering the hairline slightly as well as filling in the temples. You would need at least 1,700 - 2,000 grafts for this if you want a natural, high density looking result.

Grafts required: 1000-1500 depending on the density you are looking. Also ensure that the hair line is also taken care of. this is one of the most important aspect.

The number of grafts depends upon the quality (Thickness) of your hair shafts. The range could be as wide as 700-1300 (more when the hair is fine)

You will probably get a range of recommendations, but from what I can see I would say about 800 grafts. Of course, this assumes that you are at the very least in your late 20s, have no family history of advanced hair loss, and are amenable to taking finasteride. But again, you will probably get differing opinions about this, as well: hair transplant surgeons (and doctors in general) often disagree as to the "right" approach.Thanks for your question--I hope this was helpful.Dr. Ballon