Dark mode on a landing page: good idea or bad idea for conversion?

Dark mode has become a default on operating systems, apps, and a good share of SaaS websites over the past few years — to the point that some founders now ask for a landing page with a black background by default, without ever asking whether that choice actually serves conversion. A landing page isn't an app used for hours at a stretch, though: it's a page skimmed in a matter of seconds, where every word needs to read effortlessly and a single button needs to stand out. The question deserves a real answer rather than a decision made by trend alone.

What research says about readability

The comparison between light text on a dark background ("negative polarity") and dark text on a light background ("positive polarity") was studied well before digital dark mode took off. A landmark study published in 2013 in the journal Ergonomics by Cosima Piepenbrock, Susanne Mayr, Iris Mund, and Axel Buchner, of Heinrich Heine University Düsseldorf, tested visual acuity and proofreading performance under both polarities, in younger and older adults (Piepenbrock et al., 2013). The result: positive polarity — dark text on a light background — produced better visual acuity and better proofreading performance, and the advantage held for both younger and older adults. The authors explain it through luminance: a light background partly compensates for the decline in retinal illuminance that comes with age, which makes positive polarity more legible on average, regardless of the reader's profile.

And on cognitive performance more broadly

A more recent study, published in 2025 in the same journal by Tali Gazit, Tair Tager-Shafrir, Hua-Xu Zhong, Patrick C. K. Hung, and Vien Cheung, compared scores on online cognitive tests depending on whether the interface was displayed in light mode or dark mode, across 173 participants (Gazit et al., 2025). Cognitive scores measured were higher in light mode than in dark mode, a result consistent with the earlier work on polarity. Neither study measures conversion rate directly — conversion depends on plenty of other factors besides contrast — but both point to something useful for a sales page: for the same message, light mode takes less reading effort than dark mode.

Why dark mode is popular anyway

These findings don't explain why dark mode remains so popular, and the answer comes down to a different factor: perceived comfort in low-light environments. A dark background reduces glare when viewing a screen at night or in a dim room — which is exactly why operating systems offer an automatic dark mode tied to the time of day. That comfort under certain lighting conditions doesn't equate to better readability in absolute terms: a visitor viewing your page in broad daylight, on a desktop computer or outdoors on mobile — the most common case for a landing page reached from an ad or a Google search — doesn't have the same needs as a developer coding at night.

What this actually means for a landing page

A landing page has a different goal from an app: convince within seconds, not provide comfortable reading over a long session. Two things matter more than trends here: how fast the message is absorbed, and the contrast of the action button against the rest of the page — a principle covered in more depth in our article on background colour and price perception. A dark background is still entirely defensible for certain products — gaming, creative tools, a brand that wants to signal modernity — as long as the text contrast is handled carefully (never pure white on pure black, which produces an uncomfortable glow) and the CTA button keeps the boldest hue on the page so it genuinely stands out, as detailed in our guide to CTAs that convert. For an offer where trust and clarity come first — training, real estate, B2B services, coaching — a light background remains the safer choice, consistent with what the readability research shows.

That's the approach behind our 10 LanderKit templates (€89 each, €229 for the full pack): light backgrounds and high-contrast palettes by default, designed so a visitor arriving from an ad understands the offer at a glance instead of having to get used to an interface. The SaaS waitlist template (demo) illustrates this trade-off well: a distinctly "tech product" identity built through colour accents and typography, without sacrificing the readability that a fully dark background would compromise.

If you still want to offer a dark mode

Nothing stops you from offering both, as long as dark mode is treated as an option rather than the default on a page meant to convert quickly. A few rules limit the readability loss if you go ahead:

• Avoid pure black (#000000): use a very dark grey instead (#0f1115, for example), which reduces the halo effect around light text and is less tiring on the eyes over long sessions.
• Keep a text-to-background contrast ratio of at least 4.5:1 (the WCAG AA standard), checkable with the accessibility audit tools already mentioned in our article on landing page accessibility.
• Never lower the opacity or saturation of the CTA button in dark mode: it's precisely the element that needs to stay the most legible on the page.
• Test dark mode in broad daylight and outdoors on mobile before rolling it out widely: that's where positive polarity keeps its clearest advantage.
• If in doubt, let the visitor choose rather than imposing it: a toggle respects both their system preference and what the research on default readability shows.

Dark mode is neither a gimmick to dismiss on principle nor a standard to adopt without thinking: it's a design choice that should answer the page's actual goal. For a landing page whose job is to convince quickly a visitor who may never come back, readability generally outweighs the trend — see our anatomy of a landing page that converts for the full priority order of design decisions.