Blackout Curtain Size: 2x Rod Width, Then Halve It

Do you multiply the window width or the rod width?

You hang the pair you bought, close them at 9pm, and there's still a bright seam running down the middle and a bar of light across the ceiling. The panels cover the glass. They just don't cover the light. Almost every guide to blackout curtain size tells you to multiply the window width by 1.5 to 2 — Sleepout gives that rule, along with a length 6 to 12 inches longer than the window — though sources disagree about which object should be measured.

Take a 60-inch window and run it through both published baselines.

Multiply the window: 60 × 2 = 120 inches of fabric. Multiply the rod instead, as Deconovo instructs, and the total changes: Deconovo bases the multiplier on rod width excluding finials, which the evidence notes yields a different total than measuring off the window. EaseEase pushes further still, calling for 2 to 2.5 times the window width specifically because undersized panels leak at the gaps.

Which one you use is not settled by any published guide. No source explains what drives the difference between the two bases, though Joydeco's guide makes the point that the fabric is rarely what fails; the edges are.

That single substitution is what this piece is built on. Sleepout is blunt that blackout panels are meant to be larger than the window. The oversizing is the feature.

Quick answer

• The pick: Linen Textured, for standard 84-inch drop windows where the reader wants full darkness without a shiny synthetic face, and needs several hanging options to fine-tune coverage.
• Also worth it: NICETOWN 100%, for a nursery or shift-worker's room where the darkest possible result matters more than the drape softening at the sides.
• How this was decided: published specifications and buyer reports across 9 products, compared below.

The multiplier is doing two jobs, and only one of them is fullness

The published multipliers conflict, and no source explains why. Pillow Talk builds its size chart so both panels combined reach at least 1.5 times the window width, while its own catalogue photography runs closer to 2x.

Joydeco recommends 2 to 3 inches of centre overlap, since the centre seam is one of the most visible light sources in a room that's otherwise dark. Beyond that, no source quantifies how much extra width is needed to close an edge gap, or how far past the frame the fabric itself must land.

The rod question is unresolved in the same way. Sleepout says at least 3 to 6 inches past the frame each side; Joydeco says 6 to 15 inches each side and 6 to 10 inches above; Pillow Talk measures outside the architrave and adds 10-30cm each side. No source explains what drives the difference, so a reader cannot tell which number applies to their window.

Pack width is one panel lying flat — the error that halves your coverage

The size printed on a pack and the coverage you get are not the same figure.

Pillow Talk's buying guide is explicit about why: curtains are sold in pairs, but the size printed on the pack is one panel lying flat. So do the division in this order.

• Decide which base you are multiplying. Deconovo multiplies rod width excluding finials; Sleepout and EaseEase multiply window width.

• Divide that total by two. Deconovo's three-step method puts it plainly: for a two-panel setup, total required width ÷ 2 = the per-panel spec you need.

• Check the pack convention before you trust the number. At Pillow Talk, curtains are sold in pairs but the printed size is one panel lying flat, so pack width is not the coverage you get.

• Wirecutter treats panel width as a make-or-break spec: every one of its picks is at least 42 inches wide, most wider.

Product	Product Dimensions	Material	Item Weight	Additional Features	Suits
Linen Textured	50"W x 84"L (Pack of 2)	—	—	Balance Temperature, Blackout, Noise Reduction, Soundproof	Best linen look
NICETOWN 100%	52"W x 84"L (Pack of 2)	Polyester, Polyester Blend	2.25 kg	Thermal Insulated, Wrinkle Free	Best for nurseries
BCJJ Portable	157"L x 57"W	Polyester	0.86 kg	Blackout, Window Treatments	Best cut-to-size
Amazon Basics	52"W x 84"L (Pack of 1)	Polyester	4 pounds	Durable	Best easy care
DUALIFE	42"W x 54"L (Pack of 2)	Polyester	0.87 kg	Blackout, Energy Efficient, Light blocking, Noise Reduction, Window Treatments	Best short drop
DONREN 36	42"W x 36"L (Pack of 2)	Polyester	1.2 pounds	Blackout, Window Treatments	Best window tiers
NICETOWN Blackout	52"W x 63"L (Pack of 2)	Fabric	3 g	Bagged, Blackout, Window Treatments	Best mid length
TOWN & COUNTRY LUXE	52"W x 84"L (Pack of 2)	Polyester	0.9 kg	Noise Reduction, Thermal Insulated, Uv Protection	Best two-in-one
XTMYI Extra	70"W x 102"L (Pack of 2)	Cotton, Linen, Polyester	1.85 kg	Window Treatments	Best extra wide

Spec columns quote the listings verbatim. “Suits” is editorial.

Which one is yours

• Need package weight under 2.09 kg? → DONREN 36
• Around 2.09 kg is enough? → TOWN & COUNTRY LUXE
• Need every bit of package weight you can get? → NICETOWN 100%

Where blackout actually leaks, in order

Light comes around blackout fabric more often than through it. Joydeco's buying guide puts it plainly: the fabric is rarely what fails, and the gaps at the edges are the more common problem. The sources identify several leak points:

• Over the rod. Joydeco's fix is a track mounted flush to the ceiling, which removes the gap rather than shrinking it.
• The side channel. EaseEase notes that mounting the rod or track as close to the wall as possible measurably improves blackout performance.
• The centre split. Joydeco recommends at least 2–3 inches of overlap where the two panels meet, calling the centre seam one of the most visible light sources in an otherwise dark room. An even number of grommets helps the panels fold symmetrically so that overlap actually holds.
• The floor gap. Joydeco notes that panels reaching or lightly puddling at the floor block bottom light.

Note what's absent from that list. Fabric quality. Wirecutter tested 35 curtains and found only two, both IKEA models, that fully blocked sunlight; Wirecutter also notes that true blackout curtains block all light only when installed properly.

Caught between stock sizes: round up on width, choose length by rod height

Pillow Talk's advice when you are caught between sizes is to size up. Sleepout notes the trade-off in both directions: undersized curtains let light seep in, while oversized ones look untidy and out of proportion to the window. No source states what an oversized curtain costs you beyond that aesthetic note.

Length is a different decision, and the trick is that it isn't fully yours. Pillow Talk stocks just two drops, 223cm and 250cm, which is why the retailer tells you to buy the curtains first and hang the rod afterwards — you adjust the bracket height to the panel, not the panel to the bracket. Header type shifts the number too: Pillow Talk measures a concealed tab top from the top of the rod to 1cm above the floor, and adds 2cm for an eyelet header to allow for the lip of fabric standing above the rings. Sources part company on pooling. Joydeco says panels reaching or lightly puddling block bottom light; Pillow Talk wants 5–10cm extra for the look and specifically doesn't recommend it on blockout panels. Pillow Talk advises buying the curtains first and installing the rod afterwards so rod height can be adjusted to the curtain; no source covers hemming or shortening when a stock length falls between what the window needs. Same logic as the nightstand and lamp relationship: fix the thing you can adjust.

Linen Textured — Best linen look

• Two 50"W panels give 100" of total fabric, enough gather for a window up to roughly 50" wide
• Back tab, rod pocket, hook belt, clip ring and track compatible, so the top treatment can be changed to shift the panel closer to the wall
• But: 50" panel width is narrower than most 52" competitors, so less overlap for the same rod
• But: Rings and hooks are not included

NICETOWN 100% — Best for nurseries

• Sewn-in black liner backing behind a white face, so a pale colour still blocks light
• 52" panels give 104" total width, allowing generous overlap past the frame
• But: Grommet tops leave scalloped gaps at the header where light spills unless the rod sits high and wide
• But: 84" drop only in this listing

BCJJ Portable — Best cut-to-size

• 157" x 57" single sheet is cut to whatever the opening measures, including odd shapes and doorways
• Attaches with hook-and-loop, no drilling and no rod, so it suits rentals, RVs and travel
• But: A cut sheet, not a finished drape — no hem, no header, no decorative face
• But: Cordless inside-mount fit depends on the adhesive holding on the frame surface

Amazon Basics — Best easy care

• Machine washable, unusual among coated blackout panels
• Triple-weave fabric with a thick blackout coating on the reverse
• But: Packing wrinkles need hanging or ironing to drop out
• But: Grommet header lets light over the top edge

DUALIFE — Best short drop

• 54" length made for small windows, with 42"W panels totalling 84" of width
• Offered in nine size combinations from 42x45 up to 52x120, so the drop can be matched to the sill
• But: Rated at 85–95% light blocking, not total, and the figure drops with paler colours
• But: Rod pocket does not slide easily for frequent opening

DONREN 36 — Best window tiers

• 36" tier length suits half-height and high-set small windows where full panels are wrong
• Two 42" panels give 84" total across a small opening
• But: Blocks 85–99% depending on colour rather than fully
• But: Tiers cover only part of the window, so light enters above them

NICETOWN Blackout — Best mid length

• 63" drop fills the common gap between short tiers and floor-length 84" panels
• 52" panels with 1.6" grommets, same colour on both sides so the street view is tidy
• But: 85–99% light blocking, not absolute
• But: Grommet header gaps let light over the top

TOWN & COUNTRY LUXE — Best two-in-one

• Sheer and room-darkening layers combined on one grommet header, so a single rod does both jobs
• 52" x 84" standard pair size fits common rod runs
• But: Both layers move together, so you cannot draw only the sheer
• But: Double thickness is heavier on the rod and stacks bulkier at the sides

XTMYI Extra — Best extra wide

• 70" wide panels at 102" long, sized for 72"-wide openings and full-height doors
• Four hanging methods including 32 included hooks for pinch-pleat rings, back tab, rod pocket or clip rings
• But: Light-filtering and semi-sheer, so it will not darken a room on its own
• But: Wrong choice if blackout is the actual requirement — pair it with a blind or a blackout layer

Which of these nine suits your window

Sliding doors are one case the published guidance does not reach: no source gives sizing guidance for anything other than a standard rectangular window — no bay windows, sliding doors, arched or corner windows, or windows set close to a side wall or ceiling.

Matching the nine to the situation

For shift workers sleeping during the day, Stanford's Rachel Manber says total darkness is essential. For children napping in daylight, sleep researcher Jodi Mindell says room-darkening is preferable to full blackout, because some light helps preserve sleep rhythms. Joydeco rates room-darkening fabric without a full blackout lining at 85%–99%, though the light-blocking bands conflict across sources and none cites a test method behind its numbers.

Joydeco notes that coated polyester blackout suits windows where curtains are washed rarely, since coatings can crack or peel, whereas triple-weave polyester blocks light structurally and has nothing to crack.

This comparison is built on published guidance and what the manufacturers claim, not on light-meter readings in a dark room. Nobody here measured lux. And the published guidance itself does not agree: the multipliers, the rod extensions and the light-blocking bands all differ between sources, with no page reconciling them.

What to buy

Linen Textured, best for standard 84-inch drop windows where the reader wants full darkness without a shiny synthetic face, and needs several hanging options to fine-tune coverage.

If your case is different:

• For a nursery or shift-worker's room where the darkest possible result matters more than the drape softening at the sides: NICETOWN 100%.
• For a window whose shape or size no stock panel fits — arched, tiny, oversized or in a rental you cannot drill: BCJJ Portable.
• For someone who wants a conventional 52 x 84 blackout pair in a neutral and cares that it can go in the wash: Amazon Basics.

One caveat on the Linen Textured: 50" panel width is narrower than most 52" competitors, so less overlap for the same rod