Please refer to following size list,the dimension is laptop's.
If you are not sure,please feel free to contact with us.
Following Size is Laptop Dimension,please refer to it for choosing fitting bag.Thanks

11.6 air: 300×192×17mm
12 inch air(A1534): 280.5×196.5×13.1mm
13.3 air: 325×227×17mm
13.3 retina: 314×219×18mm
13.3 pro with touch bar: 304.1×212.4×14.9mm
13.3 pro: 325×227×24.1
15.4 retina: 358.9×247.1×18mm
15.4 pro: 364×249×24.1mm
15.4 pro with touch bar: 349.3×240.7×15.5mm

And the bag may be a little bigger than laptop,when your laptop is not Apple Macbook laptop.

11 inch sleeve
Asus Vivobook E200HA: 286 x 193.3 x 17.5 mm
Huawei Matebook:278.8 ×194.1 ×6.9mm
Surface Pro 1/2 with keyboard: 274.57 ×172.97 ×13.46mm
Lenovo Yoga3 11; 290 ×197 ×15.8mm
Lenovo IdeaPad 100s: 292×202×17.5mm

13 inch sleeve
Surface Pro 3/4 with keyboard: 292.1×201.42×8.45mm
Dell XPS 13 Series: 304×200×15mm
ASUS ZenBook TP360CA：323×220×13.9mm
Lenovo thinkpad x250: 305.5×208.5×17.7 mm
HP EliteBook 820: 310×215×21mm
Lenovo Yoga 900:324×225×14.9mm
razer blade stealth:321×206×13.1mm

15 inch sleeve
Lenovo IdeaPad 500s/700s: 338×232×13mm
Lenovo Yoga 2/3/4 Pro: 330×220×15.5mm
Asus U305/U303L Series: 323 ×226 ×12.3MM
Lenovo Thinkpad X1`Carbon: 331×226×18mm
DELL VOSTRO 5459：337×233.5×18.3mm
Lenovo thinkpad T460: 339×232.5×21mm
Lenovo Yoga 3 14: 335×230×18.3mm