This sleeve just barely fits my Sony SVS1313A190X laptop. My Sony laptop has a 13.3" screen and Sony says its measurements are 13.04 x 8.85 x 0.90". It is a very snug fit, but I think that is a good thing since there is no room for the laptop to slide around when zipped in. This Samsonite NXT 13 has an inner flap to protect your laptop from getting scratched by the zipper - you just need to make sure you place the flap around the laptop before zipping up. There are also 2 zippers, so you can fit your laptop in either way.The padding is thin; my laptop is 0.90" thick and when inside the sleeve, the sleeve measures about 1.3" thick. It will protect your laptop very nicely when you pack it inside your briefcase, backpack or suitcase. This sleeve is not meant to protect from dropping from any distance, but it will protect well from scratches and bumps.Another great feature is that this sleeve is security checkpoint friendly so you only have to remove it from your briefcase at any airport security checkpoint and they will allow it through without removing the laptop from the sleeve. I know this because I just flew to San Francisco from Dallas and both the DFW and SFO security checkpoints passed it through the x-ray without so much as a second glance.So, in summary, this sleeve will fit your Sony S13P laptop fine. Just be mindful that if you do not have the P (premium) S13 Sony, it may not fit. My S13P is .090" thick and the regular S13 (non-premium) is 0.95" thick. That 0.05" doesn't sound like much (and it isn't), but as I said, the fit is very snug with my S13P, so your regular S13 may not fit.