Why Does Curtain Pole Diameter Matter?
Choosing the right curtain pole diameter isn't just about aesthetics — it directly affects how well your curtains hang, how far the pole can span without sagging, and whether it can support the weight of your fabric. Get it wrong and you could end up with a bowed pole, drooping curtains, or a finish that simply looks out of proportion in the room.
This guide explains the four most common sizes and helps you choose the right one for your window, curtains, and interior style.
The Four Main Curtain Pole Diameters
28mm — Lightweight and Elegant
28mm poles are the slimmest option in most ranges. They suit lightweight curtains such as voiles, sheers, and unlined cotton or linen fabrics. They're a good choice for narrower windows (up to around 150cm) in bedrooms or smaller living rooms where you want a refined, understated look.
Best for: Lightweight unlined or eyelet curtains, narrower windows, contemporary or minimal interiors.
35mm — The Versatile All-Rounder
35mm is the most popular diameter for a reason. It's robust enough to carry lined curtains across standard bay and picture windows, yet slender enough to look elegant rather than chunky. Most of our wooden and metal pole ranges are available in 35mm, making it the easiest size to match with rings, brackets, and finials.
Best for: Lined curtains, standard windows up to around 200cm, most living rooms and bedrooms.
45mm — Substantial Impact
Step up to 45mm when you want the pole itself to make a design statement. The larger diameter gives a more architectural, hotel-inspired look and handles heavier fabrics — think interlined or blackout curtains — with ease. Spans of up to 300cm are achievable without a centre support bracket on many 45mm poles.
Best for: Interlined or blackout curtains, wide windows up to 300cm, traditional and country-house interiors.
50mm — Heavy Duty and Dramatic
50mm poles are our heaviest-duty option, designed for extra-large windows, floor-to-ceiling drops, and very heavy curtain fabrics. They suit grand, period, or high-ceilinged rooms where a bold, substantial look is intentional. Always check the specific pole's maximum span in the product description, as this varies by material and bracket design.
Best for: Very wide or tall windows, heavy fabric weights, period properties, statement interiors.
How to Choose the Right Diameter
Use these three questions as a quick guide:
- How wide is your window? Wider windows need a larger diameter to prevent the pole bowing in the middle. As a rule of thumb: up to 150cm → 28mm; up to 200cm → 35mm; up to 300cm → 45mm or 50mm.
- How heavy is your fabric? Hold a metre of your curtain fabric in one hand — if it feels substantial, go up a size. Interlined and blackout fabrics should always use at least a 35mm, and ideally 45mm or 50mm, pole.
- What's the style of the room? Slimmer poles read as modern and light; wider poles feel more traditional and formal. Trust your eye.
Measuring Up
Once you've chosen your diameter, the next step is getting your measurements right. Our Measuring Guide for Curtain Poles & Tracks walks you through everything — from how far beyond the window recess to extend the pole, to the correct drop for floor-length curtains.
Shop by Diameter
- Wooden curtain poles — available in 28mm, 35mm, and 45mm
- Metal curtain poles — available in 28mm, 35mm, and 50mm
- Extra long curtain poles — for spans over 300cm
- Heavy duty curtain poles — our most robust 50mm options
Still not sure which diameter is right for you? Browse our full range or get in touch — we're happy to help you find the perfect pole for your window.