# Curtain Size Calculator

Calculate the perfect curtain size for your windows. Get panel width, length, and fabric yardage based on window dimensions, fullness factor, and length.

## What this calculates

Get perfectly sized curtains every time. Enter your window measurements, choose your preferred fullness and length style, and this calculator will tell you the exact panel dimensions and how much fabric you need to buy.

## Inputs

- **Window Width** (in) — min 6, max 240 — Measure the full width of the window frame or rod.
- **Window Height** (in) — min 6, max 144 — Distance from rod to desired bottom edge.
- **Fullness Factor** — options: 1.5x - Standard, 2x - Full (recommended), 2.5x - Luxurious — Higher fullness creates richer gathers and folds.
- **Length Style** — options: Sill Length, Below Sill (+4 in), Floor Length, Puddle (+2 in extra) — Floor length is the most popular choice.
- **Number of Panels** — options: 1 Panel, 2 Panels (pair), 3 Panels, 4 Panels — Two panels (one pair) is standard for most windows.

## Outputs

- **Width Per Panel** (in) — Recommended finished width for each curtain panel.
- **Curtain Length** (in) — Finished length per panel including style adjustment.
- **Panels Needed** — Total number of curtain panels.
- **Fabric Yardage** (yd) — Total fabric needed (includes hem/header allowance per panel).

## Details

Properly sized curtains make a room look polished and intentional. The key measurements are:

  - Width: Multiply your window or rod width by the fullness factor (1.5x-2.5x) to get the total curtain width, then divide by the number of panels.

  - Length: Measure from the rod to your desired endpoint. Floor-length curtains should just kiss the floor. Puddle curtains add 2 extra inches for a luxurious pooling effect.

  - Fabric: Add 8 inches to the cut length for hems (4 inches top and bottom) and 4 inches to width for side hems.

A fullness of 2x is the most common choice and creates elegant, full gathers. For sheer fabrics, go with 2.5x for proper coverage. For a more tailored, flat look, 1.5x works well with heavier fabrics like velvet or blackout material.

Pro tip: Mount your curtain rod 4-6 inches above the window frame and extend it 3-8 inches beyond each side. This makes windows appear larger and lets in more light when curtains are open.

## Frequently Asked Questions

**Q: What fullness factor should I choose?**

A: 2x fullness is the most popular and works for most fabrics. Use 1.5x for heavy or structured fabrics like velvet. Use 2.5x for sheer or lightweight fabrics that need extra volume for privacy.

**Q: How long should curtains be?**

A: Floor-length curtains are the most versatile and modern choice. They should just barely touch or hover 1/2 inch above the floor. Sill-length curtains work well in kitchens and bathrooms. Puddle-length adds a romantic, formal look.

**Q: How high should I hang the curtain rod?**

A: Mount the rod 4-6 inches above the window frame, or halfway between the frame and ceiling for a dramatic effect. This creates the illusion of taller windows and higher ceilings. When measuring length, measure from the rod position, not the window top.

**Q: How wide should the curtain rod extend beyond the window?**

A: Extend the rod 3-8 inches beyond each side of the window frame. This allows curtains to be pulled fully open without blocking any window glass, maximizing natural light.

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Source: https://vastcalc.com/calculators/everyday/curtain-size
Category: Everyday Life
Last updated: 2026-04-21