Convert Mattress Sizes (King, Queen & More)
King is 76 × 80 in; Queen is 60 × 80. Compare Twin, Full, and international labels, then check room fit—not store prices or “best mattress” rankings.
How to Choose the Right Mattress Size
1. Consider Your Room Size
Measure your bedroom and ensure there's enough space around the bed. A good rule of thumb is to leave at least 2-3 feet of walking space on all sides.
2. Number of Sleepers
For single sleepers, Twin or Full works well. Couples should consider Queen (most popular) or King for more space. California King suits tall couples.
3. Personal Space Preferences
If you prefer more personal space while sleeping, choose a larger size. King offers the most space for couples, equivalent to two Twin XL mattresses side by side.
4. Bed Frame Compatibility
Ensure your mattress size matches your bed frame. Using a smaller mattress on a larger frame (or vice versa) can cause safety issues and discomfort.
Mattress Size & Room Matching Guide
Twin/Twin XL: Best for rooms 7' × 9' or larger. Common for children's rooms, guest rooms, and small apartments.
Full (Double): Requires at least 9' × 9' room. Good for single sleepers who want extra space or couples in tight spaces.
Queen: Minimum room size 10' × 10'. Common in master bedrooms—enough sleep space without needing a huge room.
King: Needs at least 12' × 12' room. Best for spacious master bedrooms. Offers maximum sleeping space for couples.
California King: Requires 12' × 13' room. Suits tall sleepers (over 6'2") or narrow but long bedrooms.
Special Mattress Sizes
RV Mattress Sizes
RV mattresses are typically shorter than standard sizes. RV Queen is 60" × 75" (5" shorter than standard Queen), and RV King is 72" × 75" (5" shorter than standard King).
Crib Mattress Sizes
Standard crib mattresses measure 27.25" × 51.625" (69.2 cm × 131.1 cm) according to ASTM F1425 safety standards. Mini cribs use 24" × 38" mattresses.
Non-Standard Sizes
Some mattress sizes are not part of the ISPA (International Sleep Products Association) standard but are available from certain manufacturers:
- Small Single (30" × 75"): Primarily used in UK/Europe. Limited availability in the US market. May require special ordering.
- Full XL (54" × 80"): Same width as Full but 5 inches longer. Not an ISPA standard. Limited availability, typically requires special order.
- Olympic Queen (66" × 80"): 6 inches wider than standard Queen. Very limited availability, may require custom ordering from specific manufacturers.
Note: Non-standard sizes are marked with a "Non-Standard" label in the converter. These sizes may have limited availability and may require special ordering or custom manufacturing.
Custom Sizes
Some manufacturers offer custom mattress sizes for unique bed frames or special requirements. Always measure your bed frame before ordering a custom size.
Data Sources:
- Standard mattress sizes: ISPA (International Sleep Products Association)
- RV mattress sizes: RV Industry Association
- Crib mattress sizes: ASTM F1425 Standard
- Room size recommendations: Based on industry best practices
- Last updated: January 13, 2026
Related Tools & Guides
Mattress Size Chart
Mattress dimensions for Twin through King and specialty sizes.
How to Choose Mattress Size
Compare Twin, Full, Queen, and King by room and sleepers.
Mattress Size Comparison
Side-by-side mattress size comparison.
Memory Foam vs Hybrid Mattress
Construction table for foam versus coil cores, thickness, and sheet pocket depth.
Bed Sheet Size Chart
Find the right bed sheet size for your mattress.
Bed Sheet Selection Guide
Choose sheets by mattress size and pocket depth.
Blanket Size Chart
Standard blanket sizes for beds and special purposes.
Diaper Size Chart
Baby diaper weight bands with Pampers/Huggies reference tables.