everyday life

Curtain Size Calculator

Selecting curtains involves more than measuring a window—style, proportion, and installation height all affect the final result. This calculator determines the correct length and width based on your window dimensions and desired fullness level. Whether you're hanging floor-length drapes or café-style panels, you'll get precise measurements tailored to your chosen style and aesthetic preference.

Last updated: April 23, 2026

Creators Steven Wooding, BSc Physics

Reviewers Jasmine J. Mah and Tibor Pál

6,966 people find this calculator helpful

Measuring Your Window Correctly

Accurate measurements are the foundation of proper curtain sizing. Always measure from the top of the window frame to your intended stopping point, using either inches or centimeters consistently. For floor-length curtains, measure all the way to the floor. For shorter styles, measure to the sill, apron, or café height as appropriate.

Height measurement: Start at the top of the frame and drop straight down to your target endpoint.
Width measurement: Measure the full horizontal span from the outer edge of the left frame to the outer edge of the right frame.
Rod placement: Remember that curtains typically hang 4–6 inches above the window frame, so account for this when planning your look.

Use a steel measuring tape rather than fabric tape for accuracy, and measure at least twice to confirm your numbers.

Curtain Dimension Formulas

Two core calculations determine your curtain specifications. The first adjusts for rod placement and style; the second accounts for the fullness or gathered fabric you want.

Curtain Length = Window Height + Rod Allowance

Curtain Width = Window Width × Fullness Multiplier

Window Height — Vertical distance from the top of the frame to your desired curtain endpoint
Rod Allowance — Additional inches for rod clearance and style type (typically 4–6 inches for standard styles, up to 12 inches for dramatic pooling)
Window Width — Horizontal measurement of your window opening
Fullness Multiplier — Factor determining fabric gather: 2.0 for standard, 2.5 for deluxe, 3.0 for ultra-luxe appearance

Standard Curtain Lengths and Styles

Curtains come in predictable lengths that suit different aesthetic goals and room functions. Long curtains create formal elegance, while shorter styles work well in kitchens, bathrooms, or children's spaces.

Floor-length: Grazes or just touches the floor. Lengths typically 72, 84, 96, or 108 inches. Creates luxury and formality.
Café style: Covers only the lower half of the window. Ideal above sinks, in kitchens, or for privacy without blocking light.
Sill and apron: Ends at the windowsill or a few inches below. Practical for radiators, storage, or casual spaces.
Pooled: Intentionally longer, gathering on the floor for dramatic effect. Requires extra length (typically 6–12 inches beyond floor level).

Choose your style first, then measure accordingly. Hanging the rod slightly higher can visually stretch the room and accommodate slight measurement variations.

Understanding Curtain Fullness

Fullness refers to how much fabric gathers when your curtains are closed. It directly influences the visual weight and hang of your panels, and it determines how much width you need to purchase.

Standard fullness (2×): The most common choice. Fabric width equals twice your window width. Provides a clean, tailored appearance with moderate gathering.
Deluxe fullness (2.5×): Richer, fuller folds. Creates a more upscale look with deeper pleats. Requires 2.5 times the window width.
Ultra fullness (3×): Maximum fabric and luxury appearance. Used for high-end interiors and larger windows. Demands three times the window width.

Rooms with lower ceilings benefit from standard fullness, which appears balanced. Larger spaces and formal settings suit deluxe or ultra fullness.

Pitfalls to Avoid When Sizing Curtains

Incorrect dimensions lead to awkward proportions and installation frustration.

Ignoring rod height allowance — Hanging curtains too low on the window frame shortens the visual height of the room. Always add 4–6 inches (or more for drama) above the frame. Placing the rod near the ceiling makes windows appear taller and creates a more expensive look.
Undersizing fabric width — Skimping on fullness makes curtains look thin and cheap, especially when open. Measure your window width accurately and apply the appropriate fullness multiplier. Standard 2× fullness is the safe minimum for most interiors.
Neglecting heat and traffic hazards — Long pooling curtains near fireplaces, radiators, or open flames risk damage and fire risk. Similarly, floor-length curtains in busy hallways or children's rooms become tripping hazards. Choose café or sill length in these areas.
Forgetting fabric shrinkage and hem allowance — Natural fibres shrink when cleaned. Purchase slightly longer curtains than your final target length, or ask the tailor to allow 2–3 inches for hemming. This prevents disappointment after the first wash.

Frequently Asked Questions

What's the correct way to measure my window for curtains?

Begin at the top of the window frame and measure straight down to your chosen endpoint: the floor for full-length styles, the sill for short curtains, or halfway for café panels. Measure width from the outer edge of the left frame to the outer edge of the right frame. Use a rigid steel tape measure and record measurements in inches or centimeters. Measure at least twice to verify accuracy. Remember that curtain rods typically mount 4–6 inches above the frame, so account for this when calculating length.

How do I find the right curtain width?

Multiply your window width by the fullness multiplier for your desired style. Standard fullness uses a 2× multiplier, meaning a 60-inch window needs 120 inches of curtain width. Deluxe fullness uses 2.5× (150 inches for a 60-inch window), and ultra fullness uses 3× (180 inches). If your window is 84 inches wide, standard fullness requires 168 inches of fabric. Wider curtains create more pronounced folds and a more luxurious appearance, but very narrow windows may work adequately with 1.5× fullness in minimalist settings.

What's the difference between café and floor-length curtains?

Café curtains cover only the lower portion of the window, typically reaching the sill or slightly below. They work well in kitchens, bathrooms, and children's rooms, offering privacy without blocking light. Floor-length curtains extend from near the ceiling to the floor, creating a formal, elegant impression that visually enlarges the room. Floor-length curtains typically span 72–108 inches, while café length is roughly half the window height. Choose café for casual, functional spaces and floor-length for formal rooms or when you want to enhance the sense of height.

Should my curtains touch the floor?

For a polished, high-end appearance, curtains should either just kiss the floor or graze it slightly. Curtains that fall short of the floor by more than an inch lose visual impact and elegance. If your measurements don't align with standard lengths, moving the rod up slightly (even 2–3 inches) accommodates the difference while improving room proportions. Some designers intentionally add 6–12 inches of pooled fabric on the floor for dramatic effect, but this suits formal settings and requires regular vacuuming to keep clean.

What rod allowance should I add to my measurements?

The standard rod allowance is 4 inches added to your window height measurement. This accounts for the rod's thickness and typical mounting position above the frame. For rooms with very high ceilings or when you want a dramatic effect, increase this to 6 inches. If you're aiming for pooled curtains that gather on the floor, add an additional 6–12 inches. The rod allowance ensures curtains hang at the correct height and achieve the proportions you're aiming for in your space.

Can I adjust curtains after hanging if they're the wrong length?

Yes, several adjustments are possible. If curtains are slightly too long, raise the rod a few inches—this also visually increases room height. If they're too short, you cannot extend the rod higher without looking odd; instead, consider rehemming fabric you've stored as a safety margin. If you ordered 2–3 inches longer than needed, a tailor can hem them to the precise length. However, making major length adjustments after purchase is expensive and time-consuming, so invest time in accurate measurements before ordering. Always allow a small margin for hemming when possible.

More everyday life calculators (see all)

EU to US Shoe Size Calculator Days Until June Calculator Hour Countdown Calculator Dress Size Calculator Period Products Cost Calculator Hours Between Two Times Calculator Tire Size Calculator Picture Frame Calculator