I'm 27 years old and my hairline has noticeably receded over the past few years. Estimation on number of hair grafts? (photo)

Hair transplant surgery is not about "how many grafts" you need, but about how a doctor can match your goals and expectations based on future hair loss.

If you want lower your hairline, I recommand 2500  grafts, it's will give a good result.
But it's depend of your donor area as well.

Being only 27 years old you can expect more hairloss in your future. First of all I would strongly recommend FUE method to avoid ugly linear scar that would prevent you from wearing short haircut EVER in your life. I prefer ARTAS robotic surgery since it is incredibly fast and precise but also offers protection of the existing hair. But mind that ARTAS is just a machine and has to be run by excellent surgeon and team (just like in racing you  have to have a great car but also superb driver and the team to win)As for the number of grafts depending on your desired hairline you would need 1500-2000 grafts

lotr17  Thank you for your question and photographs.  An in person consultation is  necessary to determine your best course of action.  As important as a transplant  is ; it is just as important that you consider medical therapy which may include:Platelet Rich PlasmaRogaineLaser CapBiotinPropeciaDepending upon the quality of your hair you will need approximately 2000 grafts to fill in the temples.

To restore your frontal region and hair line you would require in the range of 2,700 grafts or so.A great first step would be an online consultation. Often you can submit photos to top hair restoration surgeons for a complimentary evaluation and assessment. This should help lead you in the right direction. Having multiple consultations with different doctors will let you know your best options. 

I would say, about 1500 follicular units would suffice. The number of grafts usually varies with the kind of hairline you approve at the time of procedure and ultimately the number of square centimeters of area that needs to be filled.

Depending on the texture/quality of your donor hair (to know this you'd need to see somebody in person) it would probably only take around 1500-2000 grafts to fill in your temples. Keep in mind that it's highly recommended that your either A) wait for your hair loss to stabilize on its own, or B) use other methods like Finasteride/Minoxidil to stabilize your hair loss, before you receive a hair transplant. Good luck!

I would estimate that you would need about 1800-2000 grafts assuming your hair was of a medium thickness, 2400 if it were fine and 1500 if it were coarse