---
title: "Cot Bed and Small Single Mattress Sizes"
description: "UK cot bed (70×140 cm) and Small Single (75×190 cm) mattress sizes with plain fit notes and path to adult Single."
url: "https://bedguide.co.uk/sizing/cot-and-small-single-sizes/"
category: "sizing"
primary_entity: "cot bed and small single mattress sizes"
date_published: 2026-08-03
date_modified: 2026-08-03
---

# Cot Bed and Small Single Mattress Sizes

> A common UK cot bed mattress measures about 70 × 140 cm and must fit the cot snugly for infant safety. A UK Small Single is typically 75 × 190 cm — narrower than a standard Single at 90 × 190 cm — used for children, compact rooms and some bunks. Confirm exact manufacturer dimensions before ordering sheets or frames.

## Dimensions

| Size name | Width (cm) | Length (cm) | Width (in) | Length (in) |
| --- | --- | --- | --- | --- |
| Cot bed (common UK) (Must fit snugly in the specific cot) | 70 | 140 | 27.6 | 55.1 |
| Small Single | 75 | 190 | 29.5 | 74.8 |
| Single (reference) | 90 | 190 | 35.4 | 74.8 |

## Cot fit is a safety size problem

Unlike adult approximate sizes, cot mattresses must match the cot's internal space. A mattress that is too small creates dangerous gaps. One that is too large will not sit flat. Use the cot maker's stated centimetres.

## Progression through UK children's sizes

1. **Cot bed** — ~70 × 140 cm (verify per cot).
2. **Small Single** — 75 × 190 cm.
3. **Single** — 90 × 190 cm (standard adult/guest Single).

Adult couples' sizes begin at [Small Double / Double](/sizing/uk-standard-bed-sizes).

## Related BedGuide entries

- [UK standard bed sizes](/sizing/uk-standard-bed-sizes)
- [Mattress depth guide](/sizing/mattress-depth-guide)

## Frequently asked questions

### What size is a UK cot bed mattress?

Many UK cot bed mattresses are approximately 70 cm by 140 cm. The critical rule is a snug fit in the specific cot with gaps small enough that a child cannot become trapped — follow the cot manufacturer's stated mattress size.

### When do children move from cot to Small Single or Single?

Timing depends on height, climbing behaviour and safety guidance from carers. Dimensionally, Small Single (75×190 cm) and Single (90×190 cm) are the common next UK footprints.

---

Source: https://bedguide.co.uk/sizing/cot-and-small-single-sizes/ · BedGuide — educational encyclopedia, no affiliate commission. Facts checked against official sources where possible; see https://bedguide.co.uk/editorial-policy. Report an error: https://bedguide.co.uk/corrections.