Owners land on a curtain size calculator for one of three reasons. They already know their rod width and want the panel numbers spit back. They only have their window width and need a stand-in until the rod is installed. Or they have a ready-made panel in hand that fits wrong and want to know what should have shipped instead.

The calculator above covers all three paths. The prose around it walks each input so nothing gets mis-typed, and hands off to Two Pages custom sizing once the numbers are locked. If you want the full pilier on measuring, hanging, and installing curtains, the full install and measurement hub is the wider read.

Where the calculator output ships to

Liz Linen Drape Pleated

from $59.99/panel · 90% polyester / 10% linen · 350 gsm · pinch pleat header with 2x fullness built in · custom widths and drops to 1/2 inch · 38 colors. Final price depends on size and lining.

Use code JULY for 20% off · Free shipping over $300

Configure on Two Pages →

How to Use the Calculator (Step by Step)

Three steps: your window, your style, your numbers. The rod width is bracket-to-bracket (the tool estimates it from window width if the rod is not up yet), the ceiling height is floor to ceiling, and the header type sets the fullness multiplier. No tape handy for a field? Drag the rod, the curtains, or the sun straight in the preview.

The output is only as good as the inputs. If the rod width field takes a window measurement instead of a bracket-to-bracket number, the panel width returned will be short by 8 to 24 inches. Every input caveat sits in the next section.

The 3 Questions This Calculator Actually Answers

Under the interface, three questions get answered every time. First: is total panel width equal to at least 2 times the rod width so the folds hang clean when closed. Second: how does that total split into panels (one wide panel, two paired, three for wide runs). Third: what drop length do you order given a specific hem finish target.

Which of the three you actually need depends on where you are in the buying journey. The decision flowchart below is the shortcut.

Standard Sizes vs Your Custom Numbers (Side by Side)

Sounds obvious. Ready-made shoppers still get this wrong: the standard 5-drop ladder (63, 84, 95, 108, 120 inches) covers a fraction of American ceilings on paper, and closer to 12% of them in practice once rod placement is factored in. Custom sizing to the half inch removes the compromise.

The The Spruce standard curtain sizing chart shows the 5 stock drops assume rod placement 2 to 4 inches above the trim on 8-foot ceilings. In actual builder homes with 92-inch rod-to-floor drops and rods at 4 to 6 inches above trim, the 84 inch panel misses the floor by 8 to 10 inches, and 95 inches lands closer but still short.

The standard drop length reference spells out where each stock drop actually lands on 8, 9, and 10-foot ceilings. Once you compare the ready-made ladder against the numbers this calculator returned, the ready-made compromise reads clearly.

Your Exact Numbers Deserve an Exact Panel

Ready-made panels ship in 63, 84, 95, 108. The calculator above rarely returns one of those. Liz Linen is made-to-order to the 1/2 inch on both width and drop, so the number that just came out of the calculator is the number that ships. from $59.99/panel, 10 to 12 day lead time.

Configure Liz Linen →

How the Calculator Uses Your Inputs (The Math)

The fullness ratio formula

Here is the math the calculator applies. Total panel width equals rod width multiplied by the fullness ratio. On a 60 inch rod with a pinch pleat header, that is 60 × 2 = 120 inches of total flat panel width. On the same rod with sheers, 60 × 2.5 = 150 inches. The Two Pages measurement guide confirms the same multipliers.

Below 1.5x the panels look stretched when closed. Between 1.5x and 2x they read casual. At 2x they hang with proper folds. Above 2.5x they read luxury. The multiplier is not decoration, it is the difference between a panel that folds and a panel that pulls.

Panel count from panel width total

Panel count is a rounded division. Total panel width divided by the number of panels desired equals width per panel. If your window is under 45 inches, one panel is fine. Between 46 and 108, two paired panels. Between 109 and 144, two or three depending on how the center overlap should read. Above 144, three or four.

What to Do With Your Numbers

Real talk on the standard 84-inch panel: it misses the floor by 8 to 10 inches on almost every 8-foot ceiling with a rod mounted at the correct 4 to 6 inch overhang above the trim. Once the calculator has returned your exact drop, the next click is the Liz Linen product page, where the width and drop fields accept the numbers you just generated to the half inch.

The custom-vs-ready-made price delta is smaller than most shoppers expect. A stock 84-inch pinch pleat panel from a big-box brand runs $35 to $70 and still misses the drop by 8 inches. Liz Linen custom starts at $59.99 per panel and ships to the exact drop with 140 gsm weight, a pinch pleat header with 2x fullness built in, and 38 colors on the swatch card.

3 Input Mistakes That Break the Calculator

Where the calculator cannot save you: wrong inputs. Three specific mistakes account for most re-orders on the Two Pages returns queue.

Color Locked Next

Size solved. Color is the last variable, and it is the one most shoppers underestimate. The color that reads warm ivory on a monitor at 6pm can read cold beige on the wall at noon. If the panels are going up for a long-run install, a physical swatch check in your actual light is the cheapest insurance.

Numbers in Hand. Order to Them.

The calculator returns exact width, drop, and panel count from three inputs, applies the 2x fullness rule for pinch pleat headers automatically, and hands off numbers to the half inch. From here, two clicks route the rest: either the Liz Linen custom order form for the panel that ships to those numbers, or the wider install and measurement hub if the rod is not up yet.

FAQ

What is a curtain size calculator?

A curtain size calculator is a tool that converts your rod width, ceiling height, and header type into three output numbers: panel width per panel, total number of panels needed, and drop length. It applies the 2x fullness rule for pinch pleat headers and 1.5x for flat headers automatically, so you never have to run the multiplication by hand. The calculator on this page does that in under 3 seconds.

What size curtains do I need for a 60 inch window?

Assuming the rod is extended 8 inches past each side (76 inch bracket-to-bracket) and you want 2x fullness for a pinch pleat header, you need 152 inches of panel width total. That translates to two panels each 76 inches wide, or one very wide 152 inch panel if you have a single-track rod. The calculator returns 76 inches per panel × 2 panels when you enter these numbers.

What is the 2x rule for curtains?

The 2x rule states that total panel width should equal at least 2 times the rod width for panels to fall in proper folds when closed. On a 60 inch rod, that means 120 inches of panel width total. Sheers push the ratio to 2.5 or 3x. Flat headers can drop to 1.5x. Below 1.5x, panels look stretched and read as ready-made mistakes.

How do I calculate curtain drop?

Drop is measured from the top of the curtain ring or pinch pleat clip down to your target hem point. Sill finish ends 0.5 inch above the sill. Apron finish ends 4 inches below the sill trim. Floor kiss ends 0.5 inch above the floor. Trouser break ends 1 inch pooled. Puddle ends 3 to 6 inches pooled. Enter that number into the drop field.

How many curtain panels do I need for a 96 inch window?

For a 96 inch window with the rod extended 8 inches per side (112 inch bracket-to-bracket) and 2x fullness, total panel width needs to be 224 inches. That divides into two panels of 112 inches or three panels of 75 inches. Two paired panels of 112 inches is standard. Three panels of 75 inches gives more precise center overlap for tracks with a middle bracket.

Does the calculator work for pinch pleat curtains?

Yes. Pinch pleat headers have 2x fullness built into the pleat construction. When you select pinch pleat as the header type, the calculator applies 2x automatically. The number returned is the flat panel width, which is what you enter into the Two Pages custom order form. The pleats compress the panel to 50% of that width when hung, which is what makes them fold cleanly.

Can I use ready-made curtains with the calculator output?

Rarely. The calculator returns numbers to the half inch, and ready-made panels ship in fixed drops of 63, 84, 95, 108, and 120 inches with fixed widths of 50, 52, or 54 inches per panel. If the calculator returns 74.5 inches wide and 91 inches drop, no ready-made SKU matches. Custom sizing to the 1/2 inch is the natural next step.

What if I do not know my rod width?

Use the window width plus 8 to 24 inches as a stand-in. That accounts for the standard 4-to-12 inch overhang per side and gives the calculator enough input to return a directional answer. Once the rod is installed, re-run the calculator with the actual bracket-to-bracket measurement to lock the final custom order width. Never enter raw window width and expect the panel to fit. Better still, run the curtain rod length & height calculator first: it turns your window and ceiling into the exact bracket-to-bracket number and mounting height, then sends both straight back into this tool.