Dark Mode on Your Website: Worth It, or an Expensive Trend?

Dark mode arrived in operating systems, then in apps, and it has appeared in nearly every web design brief since. The request usually comes in the same shape: "we want dark mode, it looks more modern".

And that framing is the problem. Dark mode isn't a visual effect you switch on: it's a second complete design that has to be decided, built and maintained in parallel. It pays off on some sites and is wasted money on others, and the difference can be reasoned through.

The myth: "it's easier on the eyes"

It's the most repeated justification and it's incomplete at best. For many people, reading light text on a dark background is harder, not easier: a halo effect appears around the letters and blurs their edges. It particularly affects anyone with astigmatism, which is an enormous number of people.

What is true: in low light, a bright screen dazzles, and dark mode is genuinely more comfortable there. And on OLED screens it draws slightly less battery. Those are real advantages, but narrow ones — they don't make dark mode universally superior.

When it is worth it

The pattern is fairly clear: dark mode pays off where people spend a long time looking at the screen, and above all where they use it at night.

• Applications and dashboards somebody keeps open for hours while working.
• Digital products for technical audiences, where the expectation is established and its absence is noticed.
• Long-reading sites — documentation, extended articles — frequently consumed at night.
• Brands whose identity is already dark: there the dark theme is primary and light becomes the addition.

When it doesn't pay

On most company websites it simply doesn't. A services site gets visited for two or three minutes, almost always in daylight, with a specific decision in mind. Doubling the design for that visit changes no conversion.

What it really costs: it isn't the toggle

Building the switch is the easy part. The real cost sits in everything that has to be decided twice and reviewed twice, permanently.

• Every colour in the palette needs a dark equivalent, and it isn't "inverting": brand tones usually lose contrast on black.
• Images with white backgrounds appear as bright rectangles floating in the dark.
• The logo almost never works in both themes; a second version is usually required.
• Shadows stop working. In dark, depth is communicated with layers of lightness, not shadow.
• Every new page gets reviewed twice, and that's where the maintenance becomes permanent.

If you do it: four decisions that avoid almost every problem

The technical detail varies by stack, but the underlying decisions are the same in every case.

1. 01Respect the system preference by default. If the visitor already chose dark on their phone, don't impose light.
2. 02Offer a visible toggle and remember their choice. Someone who wants to change it wants to change it on your site, not in their system.
3. 03Never use pure black. A very dark grey reduces the halo effect and makes text considerably more legible.
4. 04Lower the saturation of brand colours in the dark theme. A vivid colour that works on white usually vibrates unpleasantly on black.

Contrast can't be improvised in either theme

The most common mistake when going dark is leaving text in a mid-grey "so it isn't so harsh". The result is text below the minimum legible contrast — and since it's the part everyone looks at, the damage is significant.

Both themes have to meet the same contrast minimums, and each has to be checked separately: passing in light tells you nothing about dark. The substance of this is in web accessibility and why it matters.

Does it affect speed?

Implemented properly, barely at all: they're colour variables, not extra resources. Implemented badly it does weigh — when each theme loads its own stylesheet, or when images get duplicated into light and dark versions without optimisation.

There's also a visible detail: if the theme is decided by JavaScript after the page paints, the user sees a white flash before dark appears. It's jarring and it affects the perception of quality. What actually moves the needle on speed is in Core Web Vitals.

The practical verdict

If you're building a company website on a finite budget, ten things return more than dark mode: speed, copy, service pages, forms, real photographs. Dark mode belongs at the end of that list, not the start.

If instead you're building something people will use for hours, it belongs in the conversation from the beginning — because adding it later, once the palette and components are settled, costs considerably more than having planned for it. General ranges are in how much a professional website costs.