---
id: css-max-width-and-min-width
title: "CSS Max-width and Min-width"
category: "Frontend"
status: "draft"
verification_status: "conceptual"
canonical_id: ""
aliases: ["max-width", "min-width", "max-height", "min-height", "responsive width"]
duplicate_of: ""
source_trust_level: "B"
confidence_score: 0.88
created_at: 2026-06-23
updated_at: 2026-06-23
review_reason: ""
merge_history: []
tags: ["css", "web", "frontend", "w3schools", "max-width", "min-width", "responsive"]
raw_sources: ["https://www.w3schools.com/css/css_height_width_min_max.asp"]
applied_in: []
github_commit: ""
---

# [[CSS Max-width and Min-width]]

## 🎯 한 줄 통찰 (One-line insight)
`max-width` sets the maximum allowed width of an element, preventing it from growing larger than that value — and it overrides `width` when `width` is larger. [S1]

## 🧠 핵심 개념 (Core concepts)
- **Four constraint properties** — `min-width`/`max-width` control minimum and maximum width; `min-height`/`max-height` control minimum and maximum height. [S1]
- **`max-width` definition** — sets the maximum allowed width of an element, preventing the element's width from being larger than the `max-width` value. [S1]
- **Accepted `max-width` values** — a length (px, cm, etc.), a percentage (% of the containing block), or `none` (the default; no maximum). [S1]
- **Override rule** — if both `width` and `max-width` are set on the same element and `width` is larger than `max-width`, the `max-width` value is used. [S1]

## 🧩 추출된 패턴 (Extracted patterns)
- **Responsive cap** — `max-width` prevents the scrollbars that appear when a fixed-`width` element is wider than a shrunken browser window. [S1]
- **Fluid-with-cap** — pairing `width: 100%` with `max-width` makes a block fill its container up to a fixed ceiling. [S1]

## 📖 세부 내용 (Details)
**The properties**
The tutorial covers four CSS properties for constraining element dimensions: [S1]
- `min-width` and `max-width` — control minimum and maximum width
- `min-height` and `max-height` — control minimum and maximum height

**The `max-width` property**
"The `max-width` property sets the maximum allowed width of an element. This prevents the width of an element to be larger than the `max-width` property value." [S1]

It accepts three value types: a length (px, cm, etc.); a percentage (% of the containing block); or `none` (default; no maximum). [S1]

**Why it matters for responsive design**
`max-width` solves a responsive design problem: when the browser window shrinks below a fixed element width, scrollbars appear. Using `max-width` prevents this issue on smaller viewports. [S1]

**Example 1** — comparing `width` vs `max-width`: [S1]
```css
.div1 {
  max-width: 500px;
  background-color: powderblue;
}

.div2 {
  width: 500px;
  background-color: powderblue;
}
```

**Example 2** — combined `width` and `max-width`: [S1]
```css
.div1 {
  width: 100%;
  max-width: 900px;
  background-color: powderblue;
}
```

**Important note**
"If you use both the `width` property and the `max-width` property on the same element, and the value of the `width` property is larger than the `max-width` property; the `max-width` property value will be used!" [S1]

**Related properties**
The page lists six dimension properties with their descriptions: `height`, `max-height`, `max-width`, `min-height`, `min-width`, and `width`. [S1]

## 🛠️ 적용 사례 (Applied in summary)
The two examples are the page's own applied cases: Example 1 contrasts a `max-width` box against a fixed-`width` box; Example 2 shows the fluid-with-cap pattern. No external project/commit applications found in the source.

## 💻 코드 패턴 (Code patterns)
Fill the container up to a fixed ceiling (language: CSS):
```css
.div1 {
  width: 100%;
  max-width: 900px;
  background-color: powderblue;
}
```

## ⚖️ 모순 및 업데이트 (Contradictions & updates)
No contradictions found in the source.

## ⚖️ 비교 및 선택 기준 (Comparison & decision criteria)
- **`width`** — a fixed content width; can force horizontal scrollbars when the viewport is narrower than the value. [S1]
- **`max-width`** — caps the width but lets the element shrink below it, so it adapts to smaller viewports without scrollbars; when both are set and `width` exceeds `max-width`, `max-width` wins. [S1]

## ✅ 검증 상태 및 신뢰도
- **상태:** draft
- **검증 단계:** conceptual (실제 적용 사례 발견 시 applied/validated로 승격 가능)
- **출처 신뢰도:** B (W3Schools — widely used educational reference, not a primary standards body)
- **신뢰 점수:** 0.88
- **중복 검사 결과:** 신규 생성 (New discovery)

## 🔗 지식 그래프 (Knowledge Graph)
- **상위/루트:** [[CSS Tutorial]]
- **관련 개념:** [[CSS Height and Width]], [[CSS Box Model]], [[CSS Padding and Box Sizing]]
- **참조 맥락:** Referenced when constraining element size for responsive layouts.

## 📚 출처 (Sources)
- [S1] W3Schools — CSS Max-width and Min-width — https://www.w3schools.com/css/css_height_width_min_max.asp

## 📝 변경 이력 (Change history)
- 2026-06-23: Initial draft synthesized from the W3Schools "CSS Max-width and Min-width" page (Astra wiki-curation, P-Reinforce v3.1 format).
