How to Measure for Bay Window Curtains: A Section-by-Section Guide

Quick answer: Plan the hanging route first, then measure a bay window section by section. Do not use the sum of glass widths as your curtain order width. First decide how you'll hang: along the bay (the rod or track follows the angles, section by section) or across the front (one straight run on a rod you mount ahead of the bay). That choice changes every measurement. For the along-the-bay route, record each straight section, each corner angle, each section's height, the obstacles, and the real path your chosen hardware follows — then convert to an order using Deconovo's custom-curtain size guide, using the rules for your chosen heading. Whether a rod can turn the corners depends on the specific hardware. Use the recording table below and the checks before you order.

Along the bay or across the front — which should you choose first?

A bay window pushes outward in three (or more) sections, so there are two very different approaches. Along the bay: the rod or track follows the shape, bending at each corner, panels close to each pane — this keeps the bay's depth and light per section, but needs hardware that can corner. Across the front: a single straight rod runs ahead of the whole bay and the panels close like a normal window — simpler hardware, but you cover the recess and sill. Decide this first, because it changes what you measure. And note: "across the front" is not automatically wall-to-wall — you measure the actual usable span of the rod you'll mount, excluding decorative finials. Record bracket and finial clearance separately; the whole wall is not automatically the usable curtain span.

Which sections, corners, and obstacles should you record?

For the along-the-bay route, sketch the window from above and record each part separately — do not sum them. Copy or print this recording table (one row per field, one column per section):

Record where each corner sits on your sketch and measure its angle with an angle finder using the hardware maker’s convention; an inside angle and a turning angle are different measurements. Note the units and where the tape begins and ends. If the supplier requires a template, use its method. Also mark brackets and mid-supports, which may stop rings from passing. Confirm radiator clearances with the appliance instructions, and check that the window can open without catching the fabric. Keep glass dimensions separate from the effective hardware path.

Where do you measure from — and does it depend on the heading?

The starting point depends on the selected heading and hardware. Deconovo’s guide uses the top of the rod for its rod-hung Grommet, Rod Pocket, and Webbing examples. For Pinch Pleat on a track, use the hook/pin position on the carrier, not the top of the track. Confirm the applicable diagram for your exact setup before entering the length. With existing hardware, measure its effective path and the drop from that correct starting point. With planned hardware, record the intended mounting line and any hardware offset, then confirm them before ordering. Measure to your chosen sill, below-sill, or floor endpoint at several positions; floors and bays may not be level. See the official measurement guide and our general measuring guide.

How do section widths become an order (Selected Width)?

The step people get wrong: the sum of the glass widths is not your order width. On Deconovo's size guide, Selected Width is the flat width of one panel before pleating, and how it maps to coverage depends on the heading:

• Grommet / Rod Pocket / Webbing: for each panel, Selected Width ≈ that panel’s allocated coverage × the chosen fullness. Use the guide's fullness — don't add a competitor's "built-in fullness" and don't multiply by fullness twice.
• Pinch Pleat: the factory pleats the panel to roughly half its flat width, so the guide states its coverage separately — follow that, and don't also apply a fullness multiplier.

Example only: one confirmed, independent 40-inch straight rod span, with two equal Grommet panels and 2× fullness. Allocate 20 inches of coverage to each panel. Order width per panel is 20 × 2 = 40 inches, with quantity 2; the combined flat fabric width is 80 inches. Do not enter 80 inches for each panel. For Pinch Pleat, a desired finished top of about 20 inches also calls for approximately 40 inches of pre-pleat Selected Width under the current guide, because the factory forms the pleats—not because another fullness factor should be applied. This example is not a whole-bay formula. On a continuous run, allocate coverage according to opening directions, stops, returns, and the chosen hardware’s overlap requirements.

What should you re-check before ordering?

Do a final pass. Openings: confirm panels won't block a window that swings or cranks open, or hit a handle. Travel and stops: on a continuous/bent track, decide which way each panel opens and where it stacks, then allocate coverage to match; check that rings or carriers can pass each corner and mid-support — on many rods they can't, which is why some bays use a bendable track or a separate rod per section (follow the hardware's instructions). Sheet: re-read the table and mark each measurement Confirmed vs. Assumed. This guide is not a calculator — window width alone can't produce a final size, because heading, panels, fullness, and hardware all factor in. When sections and hardware are confirmed, convert with the size guide, and ask us if anything is uncertain. See also are custom blackout curtains worth it and which curtain heading to use.

FAQ

How do I measure a bay window for curtains?
First choose a route along the bay or across its front. Record each relevant section, hardware path, angle, height, and obstacle. Allocate coverage to panels using the planned opening directions, then apply the current size guide. Do not use summed glass widths as the order width.

Should I add the three window widths together for the curtain size?
No. The sum of the glass widths is not your order width. Panel sizes come from your heading, planned panels, and fullness as defined in our custom-curtain size guide, where Selected Width is the flat width of one panel before pleating.

Can one curtain rod follow the angles of a bay window?
Sometimes, but not always. It depends on the rod, track, or connectors and whether rings or carriers can pass the corners and mid-support brackets. Some bays use a bendable track or a separate rod per section — check the hardware's instructions.

Do I measure every heading the same way?
No. The guide’s rod-hung Grommet, Rod Pocket, and Webbing examples start at the top of the rod. Pinch Pleat on a track starts at the hook/pin position on the carrier, not the track top. Confirm the diagram for your exact heading and hardware.

Should curtains hang along the bay or across the front?
Along the bay keeps the recess and light per section but needs corner-capable hardware; across the front is simpler but covers the recess and sill, and you measure the rod's usable span, not automatically wall-to-wall. Decide first, because it changes every measurement.

OEKO-TEX® Standard 100 certified, trusted in 21,000,000+ homes worldwide. Deconovo custom curtains, such as Solene, are made to your measurements. Confirm hardware cornering and final sizing against the size guide and your selected product options. For bendable tracks or installation, check availability and compatibility before ordering.