How long should your tie be?
The tip of your tie should just touch the top of your belt buckle. What makes it tricky is that the length is settled before the knot is finished, so you need to plan for it from the first step.
Why the buckle
A tie that stops short of the buckle looks unfinished and a little awkward, with a strip of shirt showing above your waistband. One that hangs past it looks sloppy, and it can even make you look shorter. Ending at the top of the buckle avoids both.
Fix it before you start
You can't adjust the length once the knot is tied. The tip lands wherever your starting position sends it, so the fix is always at the beginning: how far the narrow end hangs when you drape the tie around your neck.
If the tip ends up below the buckle, untie it and start again with the narrow end a little lower. If it stops above, start with the narrow end a little higher. A few centimetres makes a visible difference. Two or three tries is normal with a new tie or a new knot, and once you find the spot, remember where the narrow end sat, for example against a particular shirt button.
Bigger knots use more tie
Every wrap around the neck loop uses up length. A Half Windsor wraps one side of the loop, so it takes more tie than a Four‑in‑Hand, and a Full Windsor wraps both sides and takes more still. When you switch to a bigger knot, start with the narrow end higher than you are used to, or the tip will end up short.
Step by step: Four‑in‑Hand, Half Windsor and Full Windsor.
Tall or broad?
Most ties are about 145 to 150 cm long, which suits most people up to about 185 cm tall. If you are taller, have a long torso or a broad chest, you may find the tip never reaches the buckle however you start. Look for an extra-long tie of about 155 to 160 cm. The knot matters too: a Four‑in‑Hand uses less fabric than a Full Windsor, so it leaves more length for the blade.