Twin Bed Dimensions: Complete U.S. Guide to Twin Mattresses

A twin bed—sometimes called a single bed—is one of the most common mattress sizes in the United States. Measuring 38 inches wide by 75 inches long, it’s compact, versatile, and perfectly suited for children, teenagers, and single adults who want to maximize space without sacrificing comfort.

Because of its narrow width, a twin bed fits easily into smaller bedrooms, studio apartments, dorms, or guest rooms. Many families choose a twin mattress for a child’s first “big kid” bed because it’s affordable, easy to outfit with bedding, and long-lasting when paired with a quality, supportive mattress.

In the U.S., the standard twin mattress size is 38” wide x 75” long (96.5 cm x 190.5 cm). The twin XL—popular in college dorms—adds 5 extra inches of length, making it 38” x 80”.

To leave comfortable walking space and room for furniture, we recommend a minimum room size of 7 feet by 10 feet for a standard twin bed.

A twin mattress fits easily in smaller bedrooms or multi-use spaces—especially when paired with storage-friendly designs, such as daybeds, trundles, or bunk beds.

Families often find a twin mattress to be the perfect choice for growing kids or shared children’s rooms. The Avocado Eco Organic Kids Mattress, crafted from certified organic materials, is specifically designed for smaller sleepers and compact spaces, while maintaining exceptional comfort and durability.

If you’re shopping for a twin mattress for a bunk bed, safety guidelines recommend choosing one that’s 8 inches thick or less. This ensures the safety rail remains high enough above the mattress surface to prevent falls from occurring. The Avocado Eco Organic Kids Mattress meets these height and safety recommendations while still delivering the comfort and certified organic materials parents trust.
​

A standard twin mattress comfortably fits one person. At 38 inches wide, it’s designed for solo sleepers—whether that’s a child, teen, or adult. Two people would find it too narrow for regular use, though it can work temporarily for young children sharing a bed.
​

If you need more sleeping space for two, consider upgrading to a Full (Double) mattress, which measures 54 inches wide. You may also want to explore a trundle bed frame or a bunk bed.

Twin beds are an ideal option for:

Because of their size, twin mattresses are also a great solution for guest rooms or home offices that occasionally serve as spare bedrooms.

The main difference between a twin and a twin XL is length—the XL version is 5 inches longer.

The Avocado Green Mattress is available in both Twin and Twin XL sizes, offering a versatile, handcrafted organic option for every stage of life.

Parents often wonder when to move their child from a toddler bed to a twin mattress. A good rule of thumb is that once your child is at least 3 years old or has outgrown their toddler bed, a twin mattress provides more space and long-term value.

The Eco Organic Kids Mattress is ideal for this stage—it’s firm enough for growing children, free from harmful chemicals, and made from GOTS-certified organic cotton, GOLS-certified organic latex, and wool.

Yes. Two twin XL mattresses placed side by side equal the same dimensions as a standard king bed (76” x 80”). This setup is common for adjustable bed bases, allowing each sleeper to customize their comfort level.

Avocado offers compatible eco-conscious bed frames and adjustable bases designed to fit twin and twin XL mattresses seamlessly.

When choosing a twin mattress, what’s inside matters as much as how it feels. Many conventional mattresses use polyurethane foams, chemical adhesives, and synthetic fabrics that can off-gas volatile organic compounds (VOCs).

By contrast, Avocado’s mattresses are fully certified organic by GOTS and crafted with organic materials:

Choosing an organic twin mattress means sleeping on materials that are better for your health, your home, and the planet.

Explore: Eco Organic Kids Mattress and Avocado Green Mattress

A truly nontoxic mattress is one free from harmful chemicals, flame retardants, fiberglass, and VOC emissions. Many mattresses marketed as “green” or “natural” still contain synthetic petrochemical-based foams or adhesives to bind the layers together.

Avocado’s twin mattresses meet the highest safety standards in the industry:

These certifications ensure that every Avocado mattress—twin included—offers a cleaner, safer sleeping environment, which is especially important for children and families.

To make the most of your twin mattress:

Avocado’s collection of FSC-certified solid wood bed frames and organic bedding essentials completes a healthy, sustainable bedroom setup.

A twin mattress measures 38 by 75 inches and remains one of the most versatile and practical sizes available. Whether you’re furnishing a child’s first bed or outfitting a small guest room, a twin size offers flexibility without compromise.

By choosing a certified organic, nontoxic mattress like those from Avocado, you’re also investing in cleaner air, higher quality materials, and sustainable craftsmanship that supports your family’s health and the planet.

Sleep Better, Naturally: Explore Avocado’s Organic Twin Mattresses

A standard U.S. twin mattress measures 38 inches wide by 75 inches long.

A twin XL is 5 inches longer (38” x 80”) and fits taller sleepers or dorm beds.

Yes, for single sleepers under 6 feet tall or for smaller guest rooms.

Consider adding a bunkie board for sturdy support.

They’re made with certified organic latex, cotton, and wool — free from polyurethane foams, chemical adhesives to bind the layers, and flame retardants — and verified by OEKO-TEX®, MADE SAFE®, GREENGUARD Gold, and EWG.