Possible to Have Fat Grafting on Legs?

Chances are that you want a significant volume to change the appearance of your calves.  The amount of fat needed may be too large for your calves as the fat may not get enough oxygen to survive. It might have to be performed over several sessions.  The risk of infection and lack of survival is greater in the leg because of less circulation in this region. See a board certified plastic surgeon.

Without a picture, it's hard to say whether fat transfer would be the solution you are looking for. You have to have enough fat to make up for the difference in volume, and you have to be prepared for the possibility of needing multiple sessions to get the desired result. Only a certain amount can safely be injected at one time and some of the fat can reabsorb after injection (up to 50% in some patients). Fat grafting would be most effective near major muscles (the calf, the quad) and less effective in bony areas (around the ankles and on the front of the leg) since it needs good blood flow to survive. It is certainly a safer option than implant surgery as far as long term risks like infection and scarring, but fat transfer to the legs is more risky than in other areas of the body, so I highly recommend going to someone with a lot of experience in fat transfer. You can be prepared to spend between $3000 and $6000 depending on the amount of fat, the number of areas treated, and how long it takes to perform the procedure.

It is possible to transfer fat to the legs but it is less than an ideal recipient site and more prone to complications such as fat necrosis (lumps & bumps) as well as infection because it tends to be less vascular and more prone to edema (swelling).

It just depends on the areas that you are trying to augment.  It is hard  to augment large volumes in the legs with just fat grafting alone.  This is something that you need to see a surgeon about to really get a good idea.

Fat transfer to the legs are possible. However, patient selection is key. Consult with 3 board certified plastic surgeons who are expert and experienced in fat transfer to understand your options. The cost of fat transfer like other cosmetic surgery varies considerably across the
country and even in the same area. South Florida tends to have lower fees then
more expensive areas such as New York or Los Angeles. We charge starting at $3000 + MD
Anesthesia related costs for fat transfer for the legs. Since you can get quality work
at lower costs, patients will travel from throughout the state, the country,
and internationally to have surgery in South Florida.

To ensure that you are receiving quality work with personalized care at the
most cost effective prices, consult with board certified plastic surgeons that
own their own nationally accredited facilities. The quality must be maintained
at the highest level to maintain accreditation. The surgeons also have
incentive to hire and train quality staff (to ensure that surgery is efficient
and enjoyable), to ensure comfortable and private facilities (to encourage
referral), and to eliminate waste (to ensure that these facilities can compete
effectively).