QUOTE(KitZhai @ May 2 2025, 01:11 PM)
So I measured the window size, bought and installed the curtail rail...
If I go buy at Kaison, the size so fixed at 240cm x 260cm.

The measurements don't have to be so exact down to mm la.
The window is nearly 200cm wide and height to floor is nearly 240cm. (180 + 60cm)
If the curtain is 240cm wide and 260cm high, then the width is okay, but the length is 20cm longer. This you can adjust by putting the curtain rail higher.
Btw, the curtain rail (which you can cut to length) should be about 10 cm from the window edge on both sides.
Edit... Curtain have to be much wider than the window for full coverage as the curtain will be pleated by the hooks used and making it narrower.
This post has been edited by ScooterBoi: May 2 2025, 03:53 PM