Hard to tell for sure without a decent Harpenden skin caliper test (and experienced tester) or bioelectrical impedance testing, both btw should be available at a well equipped gym or college.
Going by your abs I'd say you got to be about 5% but your shoulders and back look a tad smoother, which I'd estimate at around 9%. This could be more to do with the camera and lighting etc., and not truly reflective. Why not just take an average of this or all the other suggestions of your BF% too.
I think it is reasonable to assume your overall BF% is at 7% by what we can see in your shots.
You look a lot lot bigger than 140lbs in your pics. I thought at first glance you were about 5'10" and 190lbs!
I aspire to look like you do. Good work...and all at a home gym and attentive diet
NB: As a person ages - not all but most - their metabolic rate starts to slow down and fat mass increases as FFM slowly begins to decrease (as we approach late middle age to old age).
As a rule of thumb, after 24 years old most males experience a slow down in metabolic rate of around 1% to 2% per year; often attributed to the sluggish thyroid and stuff. That's why so many guys in their forties (me for one) start worry about keeping the fatty weight down without sacrificing hard to build and maintain muscle mass.
Please Scroll Down to See Forums Below 
