Yes, it should be possible to charge a Surface Pro 4 (SP4) with this (provided a suitable cable for the Surface is available). The battery capacity of an SP4 is apparently 5'087 mAh, with this PowerBar it should theoretically (!) be possible to charge an SP4 5.9x. Test reports showed that an SP4 needs about 160 minutes to be fully charged (via PowerBars - of course, there are differences). As always, all information without guarantee ;-)