CSS min(), max(), and clamp() let a property adapt to its context while obeying limits: min() chooses the smallest candidate, max() chooses the largest, and clamp() keeps a preferred value between a floor and a ceiling. They are useful for responsive widths, spacing, and type without a stack of breakpoint overrides.
Which function should you use?
| Design need | Function | Example | What it does |
|---|---|---|---|
| Use the smaller of several values, imposing a ceiling | min() |
width: min(90%, 70rem); |
The width is at most 70rem and otherwise follows 90% of its containing context. |
| Use the larger value, imposing a floor | max() |
font-size: max(1rem, 2vw); |
The font size is at least 1rem and can grow when 2vw is larger. |
| Scale fluidly with both a floor and a ceiling | clamp() |
font-size: clamp(1rem, 2.5vw, 2rem); |
The preferred value, 2.5vw, applies within the bounds; below or above them the relevant bound applies. |
Choose based on whether the design needs a ceiling, a floor, or both, and whether a fluid preferred value makes sense. These are patterns, not universal design tokens: choose values that fit the actual content and test them at narrow and wide sizes.
How does min() work?
min(a, b, ...) evaluates its comma-separated arguments and returns the smallest resolved value. For example:
.page {
width: min(90%, 70rem);
margin-inline: auto;
}The width tracks 90% of its containing context until that value would exceed 70rem; then the cap wins. This creates a fluid content area with a maximum width. The percentage is resolved according to the property and its containing context, so it is not a universal viewport percentage.
#1 Best Overall
- Read Before You Buy — No Video Output: These adapters support charging and USB 2.0 data transfer, but cannot transmit video signals. Except for standard USB webcams (which use USB data only), they are not compatible with HDMI/DisplayPort cables, video-capable USB-C hubs, or docking stations with video output.
- Convert USB-A Ports to USB-C: Designed to connect USB-C earphones, cables, flash drives, card readers, and other USB-C accessories to standard USB-A ports. Plug-and-play with no drivers or software required.
- Aluminum Alloy Housing: Built with a sturdy aluminum alloy shell that aids in heat dissipation and protects against daily wear and scratches. Designed to maintain a stable and secure connection.
- Compact & Travel-Friendly: The ultra-compact design allows the adapter to stay plugged into your device without blocking adjacent ports or adding bulk, reducing wear and tear on your original USB ports.
- 12-Month Warranty: Backed by a 12-month manufacturer warranty for peace of mind. Designed to meet strict quality control standards for reliable everyday performance.
To see the comparison directly, width: min(50vw, 400px) uses whichever is smaller at the current viewport: half the viewport width or 400px.
How does max() work?
max(a, b, ...) returns the largest resolved argument. It is useful when a value should grow responsively but must not fall below a minimum:
Rank #2
- 5-in-1 USB-C Hub: Experience comprehensive connectivity featuring a Power Delivery input, two USB-A 2.0 ports, a USB-A 3.0 port, and an HDMI port. (Note: The USB-C power delivery input port is only for connecting an external wall charger to power your laptop and cannot power peripheral devices.)
- 90W Pass-Through Charging: Achieve optimal charging with 90W pass-through power to your laptop, supported by a total input of 100W, with the hub reserving 10W for operational efficiency. (Note: Wall charger not included.)
- Quick Data Transfers: Accelerate your productivity with rapid data transfers using a high-speed 5Gbps USB 3.0 port and two 480Mbps USB 2.0 ports.
- 4K HDMI Display: Enhance your visual experience with a hub capable of delivering 4K resolution at 30Hz in both mirror and extend modes. Please note that this hub is compatible with MacBook (macOS 12 and newer), Windows 10 and 11, ChromeOS, and laptops equipped with DP Alt Mode and Power Delivery. Note: This device is not compatible with Linux.
- What You Get: Anker USB-C Hub (5-in-1, 4K HDMI), welcome guide, 18-month warranty, and our friendly customer service.
.label {
font-size: max(1rem, 2vw);
}When 2vw is smaller than 1rem, the 1rem floor wins. When 2vw is larger, the text can grow. A viewport-based term on its own does not impose a floor or ceiling; add the constraint the design actually needs.
How does clamp() work?
clamp(minimum, preferred, maximum) is the concise way to express a lower bound, a fluid preferred value, and an upper bound together:
The Tool Desk
Outbyte PC Repair FREERepair Windows errors before they cause bigger problemsFix Now →Outbyte Driver Updater FREEScan for outdated or missing drivers - takes under a minuteDriver Scan →Rank #3
- Sleek 7-in-1 USB-C Hub: Features an HDMI port, two USB-A 3.0 ports, and a USB-C data port, each providing 5Gbps transfer speeds. It also includes a USB-C PD input port for charging up to 100W and dual SD and TF card slots, all in a compact design.
- Flawless 4K@60Hz Video with HDMI: Delivers exceptional clarity and smoothness with its 4K@60Hz HDMI port, making it ideal for high-definition presentations and entertainment. (Note: Only the HDMI port supports video projection; the USB-C port is for data transfer only.)
- Double Up on Efficiency: The two USB-A 3.0 ports and a USB-C port support a fast 5Gbps data rate, significantly boosting your transfer speeds and improving productivity.
- Fast and Reliable 85W Charging: Offers high-capacity, speedy charging for laptops up to 85W, so you spend less time tethered to an outlet and more time being productive.
- What You Get: Anker USB-C Hub (7-in-1), welcome guide, 18-month warranty, and our friendly customer service.
.heading {
font-size: clamp(1rem, 2.5vw, 2rem);
}At sizes where 2.5vw falls between 1rem and 2rem, the preferred value applies. If it falls below the minimum, the result is 1rem; if it exceeds the maximum, the result is 2rem. The bounds describe the allowed range, while the middle expression describes how the value should adapt within it.
The middle argument does not have to use vw. A percentage or another valid expression may suit the property and design better. Pick it based on what should drive the change, then check the rendered result across the content’s actual contexts.
Rank #4
- Dual Converters, Infinite Potential：Includes 2× USB C male to USB A female adapters and 2× USB A male to USB C female adapters. Perfect for a wide range of uses—tablets with Bluetooth keyboards, expand USB ports on macbook, and more. Two different converters for all your daily needs
- Next-Level 10Gbps & 3A Charging: No more slow 480Mbps, this usb to usb c adapter has a transfer speed of up to 10Gbps, allowing you to do more transferring in less time. This usb adapter fits both USB A and USB C charger, supporting up to 3A fast charging
- Upgraded Exquisite Craftsmanship: With an aluminum alloy housing and metal connector, the usbc to usb adapter is extremely durable and sturdy. Rigorously tested to withstand more than 10,000 times of plugging and unplugging, ensuring long-lasting performance
- Broad Compatible: The usb c to usb adapter widely supports all USB C/ USB A devices like laptops, tablets, cellphones, car chargers, and phone chargers. Such as compatible with MacBook Pro/Air 2023/2022, Thunderbolt 4/3 Devices,Apple MagSafe Watch 9/8/7/SE/Ultra, iPad Pro 2022/2021, Samsung Galaxy S23/S20/S10, and iPhone 17/16/15 Pro. Plug and play
- Please Note: To reach 10Gbps speed, keep the cable under 3.3 ft. For USB A Male to USB C adapters, try flipping the USB C connector. USB C Male to USB A adapters support bidirectional 10Gbps transfer within 3.3 ft
Can the functions mix units or be combined?
CSS math functions can compare compatible expressions using different units, such as a percentage and a length. Their values must still be valid for the property, and percentages resolve in that property’s context. Do not assume every arbitrary mix of units is meaningful for every CSS property.
min() and max() can also be combined with each other, used inside clamp(), or combined with calc(). For example, nested expressions can encode more complicated constraints, but they are harder to inspect. Prefer the shortest expression that clearly states the design rule.
Recommended Free Tools
Best Value
- 5-in-1 Connectivity: Equipped with a 4K HDMI port, a 5 Gbps USB-C data port, two 5 Gbps USB-A ports, and a USB C 100W PD-IN port. Note: The USB C 100W PD-IN port supports only charging and does not support data transfer devices such as headphones or speakers.
- Powerful Pass-Through Charging: Supports up to 85W pass-through charging so you can power up your laptop while you use the hub. Note: Pass-through charging requires a charger (not included). Note: To achieve full power for iPad, we recommend using a 45W wall charger.
- Transfer Files in Seconds: Move files to and from your laptop at speeds of up to 5 Gbps via the USB-C and USB-A data ports. Note: The USB C 5Gbps Data port does not support video output.
- HD Display: Connect to the HDMI port to stream or mirror content to an external monitor in resolutions of up to 4K@30Hz. Note: The USB-C ports do not support video output.
- What You Get: Anker 332 USB-C Hub (5-in-1), welcome guide, our worry-free 18-month warranty, and friendly customer service.
What should you check for responsive and accessible text?
- Test actual content at narrow and wide viewport sizes. A fluid value that looks fine in one layout may become too small or too large in another.
- When
clamp()controls text size, MDN advises that the maximum relative length should be no less than twice the minimum relative length. This helps preserve room for enlargement; the formula alone does not establish that a page is accessible. - Test text enlargement and page zoom in the real interface, and confirm that text remains readable without clipping or hiding essential content.
- Keep the containing context in mind for percentages; the comparison only has the intended meaning once each expression resolves for its property.
Are these functions supported in browsers?
MDN labels min(), max(), and clamp() Baseline Widely available and documents browser availability since July 2020. That status is not a promise for every legacy browser or embedded web view. If older clients matter, check the project’s actual support matrix and test those clients.
Common mistakes and fixes
- Confusing a function with a property:
min()andmax()are math functions written inside a property value; they are not the same as properties such asmin-widthandmax-width. - Using only a fluid term: A value based only on viewport size can become too small or too large. Use
max()for a floor,min()for a cap, orclamp()when both are needed. - Assuming a percentage means viewport width: Check which containing context the property uses. If the intended reference is the viewport, select a viewport-relative expression deliberately.
- Over-nesting: Nested functions are valid, but difficult-to-read expressions are harder to maintain. Simplify them or use a clearer rule when the extra constraint is not needed.
- Choosing bounds without checking text enlargement: Test the actual page with zoom and text resizing; a mathematically bounded size can still be too restrictive for readers.
Or skip the browser setup
If you need a screenshot of a page demonstrating these CSS rules, you can capture one without setting up a browser. ScreenshotNeo is a website screenshot API and MCP server. Its one-request API returns an image or PDF; for example, this cURL request saves a WebP screenshot of the CSS reference page at MDN:
Quick Recap
curl -G "https://api.screenshotneo.com/v1/shot" -d access_key=YOUR_API_KEY --data-urlencode url=https://developer.mozilla.org/en-US/docs/Web/CSS/clamp -o shot.webpSee the ScreenshotNeo API documentation for request options. It removes cookie banners, newsletter popups, and chat widgets before the shot; bot checks, blank pages, and failed loads are never billed. Its MCP server lets AI agents take screenshots. The Free plan includes 1,000 screenshots a month with no card, and paid plans start at $5 for 3,000. Sign up for free.
Product prices and availability are accurate as of the date/time indicated and are subject to change. Any price and availability information displayed on Amazon at the time of purchase will apply.
Free tools Windows power users keep installed
One-click scans. No signup required.
