A small double bed is typically 120 cm wide and 190 cm long (about 4 feet by 6 feet 3 inches). This size is also commonly referred to as a three-quarter bed and sits between a single bed and a standard double in many regions. Key takeaways by region:

• UK and Ireland: Small double often defined as 120 cm × 190 cm (4′ × 6′3″) [citable standards vary by retailer, but this is the most common measurement].
• Canada/US-inspired terminology: The “small double” label isn’t universally used; when it appears, it usually corresponds to about 137 cm × 190 cm (54–55 inches × 190 cm) in some listings, but many sources align with the 120 cm × 190 cm size.

Practical notes:

• Accessory fit: Fitted sheets, duvets, and mattress toppers may have more limited availability for this width, so check product measurements carefully before purchasing.
• Sleeping comfort: Two adults sharing a small double can feel tight since each sleeper has about 60 cm (approximately 24 inches) of width.

If you tell me your country or region (and whether you’re shopping for sheets, a mattress, or a bed frame), it can help confirm the exact standard measurements used in that area and ensure compatibility.