Guides
Correct tie length: where the tip should end
Use the waistband, not a rigid centimetre rule, to set tie length. Body proportions, knot choice and trouser rise all change the result.
Use the waistband as your reference
With a conventional trouser rise, the point of the wide blade should finish around the middle of the belt buckle. Without a belt, use the top of the waistband. This connects shirt, tie and trousers into one continuous vertical line. A noticeably short tie compresses the torso, while a tip hanging far below the waistband looks untidy.
Check length only after putting on the complete outfit. High-rise trousers require less visible tie than low-rise trousers, so a universal measurement is less useful than the relationship to the clothes you are wearing.
Allow for knot and body proportions
Every knot consumes a different amount of fabric. A Four-in-Hand uses relatively little, a Half Windsor more and a full Windsor the most. Start with the wide blade lower when tying a fabric-intensive knot. Mark the initial position of the narrow blade against a shirt button and adjust it on the second attempt.
Tall men do not automatically need an extra-long tie. Torso length, neck size, trouser rise and knot all matter. Consider extra length when the wide tip is correct but the narrow blade can no longer sit securely behind it.
Control the narrow blade
The narrow blade should remain shorter and pass through the keeper loop at the back. If it hangs below the wide blade, change the starting position rather than tucking it into the shirt. A tie bar can connect both blades to the shirt placket, but it cannot correct the wrong length.
After tying, set the tip first, centre the knot second and arrange the collar last. Repeated forceful pulling puts unnecessary strain on the fabric.
A quick mirror check
Button the jacket, stand naturally and look at the full silhouette. The tie should run down the centre, reach the waistband and remain controlled between the jacket fronts. Sit down briefly: the knot should stay at the collar and the tip should not spread far across the lap.
A difference of one or two centimetres is rarely important. The visual relationship among knot, collar, tie width, lapel and waistband matters more than mathematical precision.