Curtain Size Calculator - What Size Curtains Do I Need?
Use this free curtain size calculator to find the perfect curtain dimensions for your windows. Enter your window measurements, choose your curtain style and hanging height, and get instant recommendations for rod width, curtain length, and panel width.
How to Measure for Curtains
Getting the right curtain measurements ensures your window treatments look polished and professional. Proper measurement involves more than just the window opening itself; you need to consider the rod placement, desired fullness, and hanging style.
Measuring Window Width for Curtains
Start by measuring the width of your window frame from outside edge to outside edge. The curtain rod should extend 6 to 8 inches beyond each side of the window frame, which allows curtains to be pulled fully open without blocking the glass. This wider rod also makes the window appear larger. For a standard look, the total curtain fabric width should be 1.5 times the rod width. For a luxurious, heavily gathered look, use 2 times the rod width.
Hanging Height Tips
Where you mount your curtain rod dramatically affects the room's perceived proportions. Hanging curtains higher than the window frame makes the window and the room appear taller. The standard recommendation is to mount the rod 4 to 6 inches above the window frame. For maximum visual impact, mount the rod at or near the ceiling line. This is especially effective in rooms with standard 8-foot ceilings, where ceiling-mounted curtains create the illusion of much greater height.
Understanding Fullness Ratios
Fullness ratio refers to how much wider the curtain fabric is compared to the rod width. A 1.5x fullness ratio is the minimum for a decent gathered appearance and is suitable for casual or modern spaces. A 2x ratio provides rich, full folds and works well in formal rooms. A 2.5x or 3x ratio creates deep, dramatic pleats typically seen in formal drapery with pinch-pleat or goblet-pleat headings. Flat panel curtains use a 1x ratio for a clean, contemporary look.
Standard Curtain Sizes
Ready-made curtains come in standard lengths: 63 inches, 84 inches, 95 inches, and 108 inches. The 63-inch length works for sill-length treatments on standard windows. The 84-inch length is the most popular and suits most windows with rods mounted a few inches above the frame. The 95-inch length works well for floor-length curtains in rooms with 8-foot ceilings. The 108-inch length is ideal for rooms with higher ceilings or for creating a puddle effect.
Curtain Size Chart by Window Width
Quick reference for curtain sizes based on common window widths (using 1.5x fullness, rod extending 8" each side):
| Window Width | Rod Width | Total Fabric Width | Per Panel (2 panels) | Best Standard Length |
|---|---|---|---|---|
| 24" | 40" | 60" | 30" | 63" or 84" |
| 36" | 52" | 78" | 39" | 84" |
| 48" | 64" | 96" | 48" | 84" or 95" |
| 60" | 76" | 114" | 57" | 95" |
| 72" | 88" | 132" | 66" | 95" or 108" |
For 2x fullness (luxurious look), multiply the "Total Fabric Width" by 1.33. For single-panel treatments, use the full fabric width for one panel.
Curtain Fabric Types: Which Material Is Best?
The fabric you choose affects light filtering, privacy, drape, and how the curtain hangs. Here's how the most common curtain fabrics compare:
| Fabric | Weight | Light Filtering | Privacy | Best For |
|---|---|---|---|---|
| Sheer/Voile | Very light | Minimal — softens light | Low | Living rooms, layered with drapes |
| Linen | Light-medium | Moderate — filters gently | Moderate | Casual living rooms, dining rooms |
| Cotton | Medium | Moderate to good | Good | Bedrooms, family rooms, versatile |
| Polyester | Medium | Good | Good | Budget-friendly, wrinkle-resistant |
| Velvet | Heavy | Excellent — blocks most light | Excellent | Formal rooms, home theaters, cold climates |
| Blackout | Heavy (lined) | 100% light blocking | Complete | Bedrooms, nurseries, shift workers |
Linen is the most popular choice for modern homes thanks to its relaxed, textured look, but it wrinkles easily and offers limited privacy. Cotton is the best all-around fabric — it drapes well, is machine-washable, and works in any room. Velvet provides excellent insulation and can reduce heating costs by 10-15% in winter by trapping a layer of air against cold windows. Blackout curtains use a foam-backed lining or tightly woven fabric to block 100% of light — essential for bedrooms where any light disrupts sleep.
Curtain Heading Styles Compared
The heading (the top of the curtain where it attaches to the rod) determines how the curtain hangs, how much fabric you need, and the overall look:
| Heading Style | Fullness Ratio | Look | Price Range | Best For |
|---|---|---|---|---|
| Rod Pocket | 1.5–2x | Casual, gathered | $ | Bedrooms, casual rooms |
| Grommet/Eyelet | 1.5x | Modern, even folds | $$ | Living rooms, modern decor |
| Tab Top | 1.5x | Relaxed, visible rod | $ | Casual, cottage style |
| Pinch Pleat | 2–2.5x | Formal, tailored pleats | $$$ | Formal rooms, dining rooms |
| Ripple Fold | 2x | Clean, uniform S-curves | $$$ | Hotels, modern luxury |
| Flat Panel | 1x (no extra) | Minimalist, no gathers | $ | Contemporary, decorative only |
Grommet curtains are the most popular heading style for ready-made curtains because they create even, consistent folds and slide smoothly along the rod. Pinch pleat is the classic choice for custom drapes and formal rooms — the pleats are sewn in permanently, creating a tailored look that stays neat. Rod pocket is the most affordable option but is harder to open and close because the rod threads through the fabric.
How to Hang Curtains on Bay Windows
Bay windows require special planning because they have angled sections. There are three main approaches:
Option 1: Individual Rods per Section
Mount a separate curtain rod on each flat section of the bay window. This is the most common approach and works with any curtain style. Measure each section independently (width and height) and calculate fabric for each panel separately. Use rod brackets that allow the rods to sit close to the wall at each angle.
Option 2: Flexible Bay Window Rod
A flexible curtain rod bends to follow the bay window shape as one continuous piece. This creates a cleaner look with no gaps between sections. Measure the total width along the bay window curve from wall to wall. Flexible rods work best with lightweight fabrics (sheer, linen, light cotton).
Option 3: Ceiling Track System
A ceiling-mounted track (like a hospital curtain track) follows the exact contour of the bay. This is the most seamless and professional option. Tracks allow curtains to glide smoothly around the angles and can support heavier fabrics like velvet and blackout. A ceiling track costs $50-$150 for a standard bay window.
Bay Window Measurement Tips
- Measure each flat section of the bay separately
- Add 3-4 inches overlap where sections meet at the angle
- Use 15% waste factor for bay windows (more cutting waste from angles)
- Measure from the highest point if the bay ceiling is angled
- For privacy, pair sheers on the bay with drapes on the outside wall
Curtain Rod Types Compared
| Rod Type | Price | Max Weight | Best For |
|---|---|---|---|
| Standard decorative rod | $15–$60 | 15–20 lbs | Light to medium curtains, most rooms |
| Heavy-duty decorative rod | $40–$120 | 30–45 lbs | Velvet, blackout, or heavy drapes |
| Tension rod | $8–$25 | 5–10 lbs | Sheers, lightweight curtains, rental apartments |
| Traverse rod | $30–$80 | 20–30 lbs | Frequently opened/closed curtains, pinch pleat |
| Ceiling track | $30–$150 | 25–40 lbs | Bay windows, room dividers, modern/clean look |
Tip: Always use a center support bracket for rods longer than 48 inches to prevent sagging. For heavy curtains (velvet, blackout), mount brackets into wall studs, not just drywall anchors. Traverse rods with a pull cord or wand are the best choice for curtains you open and close daily because they reduce wear on the fabric.
Curtain Costs: What to Budget (2026 Prices)
Curtain costs vary dramatically based on fabric, heading style, and whether you buy ready-made or custom. Here's what to expect for a standard 48-inch window:
| Option | Per Panel | Per Window (2 panels) | 5 Windows |
|---|---|---|---|
| Ready-made polyester (budget) | $15–$30 | $30–$60 | $150–$300 |
| Ready-made cotton/linen (mid-range) | $30–$80 | $60–$160 | $300–$800 |
| Ready-made blackout | $25–$60 | $50–$120 | $250–$600 |
| Custom pinch pleat (mid-range) | $100–$250 | $200–$500 | $1,000–$2,500 |
| Custom velvet/silk (luxury) | $200–$500+ | $400–$1,000+ | $2,000–$5,000+ |
Prices are for 84-inch length panels on a 48-inch window. Add $15-$60 per window for a curtain rod. Custom curtains include fabric, heading, and lining. Professional installation (hanging) adds $50-$150 per window.
Frequently Asked Questions
How wide should curtains be compared to the window?
The total curtain width should be 1.5 to 2 times the width of the curtain rod. The rod itself should extend 6 to 8 inches past each side of the window frame. So for a 48-inch window, the rod would be about 64 inches wide, and you would need 96 to 128 inches of total curtain fabric. Split between two panels, each panel should be 48 to 64 inches wide. A 1.5x ratio provides a standard look; 2x gives a more luxurious appearance.
How high should I hang curtains above the window?
Hang curtains 4 to 6 inches above the window frame for the best look. This is the most popular approach and visually elongates the window. For a more dramatic effect, hang the rod at ceiling height, which creates the illusion of taller windows and a grander room. At minimum, mount the rod at the top of the window frame. Never mount it below the frame top.
Should curtains touch the floor?
It depends on the style you want. Standard curtains hover about 1/2 inch above the floor for a clean, tailored look and easy cleaning. Floor-length curtains just barely kiss the floor for a more elegant appearance. Puddle curtains extend 2 to 3 inches onto the floor for a dramatic, romantic look best suited for formal spaces. For kitchens, bathrooms, or above radiators, sill-length curtains that end at or just below the window sill are the most practical choice.
What standard curtain length should I buy?
Ready-made curtains are available in 63-inch, 84-inch, 95-inch, and 108-inch lengths. Measure from the rod to your desired ending point and choose the closest standard length. The 84-inch length is the most versatile and works for most standard windows with rods mounted 4 inches above the frame. If you fall between sizes, choose the longer option as curtains can be hemmed but not extended.
How many curtain panels do I need?
For most windows, use 2 panels (one on each side). For wider windows over 60 inches, consider 3-4 panels for proper fullness. Each panel should be at least 1.5x the width of its section of the rod. For a bay window, use one panel per window section. Single-panel curtains work for narrow windows under 30 inches.
What size curtain rod do I need?
Your curtain rod should extend 6-8 inches beyond each side of the window frame. For a 48-inch wide window, use a rod that's 64 inches (48 + 8 + 8). This allows curtains to stack to the sides when open without covering the glass. Standard rod diameters are 1 inch (decorative) or 5/8 inch (functional). Use a support bracket in the center for rods over 48 inches to prevent sagging.
How do I measure a bay window for curtains?
Measure each flat section of the bay window separately (width and height) for individual rods, or measure the total curve from wall to wall for a flexible rod or ceiling track. Add 3-4 inches of overlap where sections meet at each angle. For individual rods, calculate fabric for each panel independently. For a flexible rod or ceiling track, add all section widths together plus the overlaps. Use a 15% waste factor for bay windows because the angles create more cutting waste.
What is the best curtain fabric for bedrooms?
Blackout curtains are the top choice for bedrooms because they block 100% of light for better sleep quality. If you prefer a softer, more decorative look, use cotton or linen curtains paired with a separate blackout liner ($10-$20 per panel). Velvet curtains work exceptionally well in cold-climate bedrooms because they block light and provide thermal insulation, reducing heat loss through windows by 10-15%. For children's rooms and nurseries, blackout polyester curtains are the most practical — they're washable, affordable, and completely darken the room.
How much do curtains cost for a whole house?
For a typical home with 10-15 windows, ready-made curtains cost $300-$1,200 total at the budget to mid-range level ($30-$80 per window for two panels). Custom curtains run $2,000-$7,500+ for the same number of windows. Add $150-$900 for curtain rods ($15-$60 per window). If you hire someone for professional installation (mounting rods and hanging curtains), expect to pay $50-$150 per window, or $500-$2,250 for a whole house. The biggest cost saver is buying ready-made curtains and installing the rods yourself.