Buying a monitor 2026: learn the PPI sum and size versus resolution answers itself

Choosing a monitor usually comes down to "bigger is better" or "sharper is better", and both are wrong when the two are paired badly.

This article gives you one calculation that lets you decide size and resolution yourself without trusting anyone, then covers the rest.

PPI: the sum that answers size versus resolution in one line

Photo: Lucasbosch — CC BY-SA 4.0 (Wikimedia Commons)

PPI (pixels per inch) is how densely packed the pixels are, and it is what decides whether text looks crisp or you can see jagged edges.

PPI = √(width² + height²) ÷ diagonal in inches

Apply it to the pairings actually sold:

Photo: ALexL33 — CC BY-SA 3.0 (Wikimedia Commons)

⚠️ Two things the table settles immediately:

1. A 24-inch 1080p and a 32-inch 1440p are exactly equally sharp at 91.8 PPI. A bigger screen is not a sharper screen; it is a bigger one. Sharpness depends on the ratio of pixels to inches, not on either number alone.
2. 27-inch 1080p is the pairing to avoid. At 81.6 PPI it is coarser than everything else in the table — the same pixels stretched larger with nothing gained. And it is the best-selling pairing in the budget segment, because "27 inch" sells more easily than "24 inch".

Does higher resolution buy space or sharpness?

This is where people get confused, and the answer depends on your scaling setting:

• At 100% scaling, higher resolution means more desktop area — 2560×1440 has 78% more area than 1920×1080, which means genuinely usable side-by-side windows.
• At 150–200% scaling, higher resolution means more sharpness with the same area, because everything is enlarged back.

⚠️ So 4K on a 27-inch screen is paying for sharpness, not space. At 163 PPI almost nobody can read text at 100%, so you move to 150%, which gives back exactly the working area of 1440p. If the goal is desktop space, 27-inch 1440p delivers the same thing for far less.

⚠️ Viewing distance changes the answer too. The further you sit, the less PPI you need. A shallow condo desk that forces you close makes a 27-inch 1080p look worse still, while the same screen on a deep desk may be acceptable.

Refresh rate: where it is still worth paying

Refresh rate is how many times a second the screen redraws, and its returns diminish sharply:

⚠️ The first step up from 60Hz gives the most, and most people should stop at 120–144Hz. Beyond that you pay considerably more for progressively less.

⚠️ The graphics card has to produce those frames. A 240Hz monitor with a card managing 80 fps in your games is paying for a number you never reach. Check your card's real frame rates in the games you play, then pick a refresh rate to match — and if upgrading, spend on the GPU first (see AMD vs Intel for the CPU side).

Do not confuse refresh rate with response time — refresh rate is frames per second; response time (ms) is how fast a pixel changes colour. Advertised response times are usually measured in the most aggressive overdrive mode, which produces visible ghosting trails and is arguably worse than a slightly slower pixel. Trust measured reviews, not the box.

Panel types, and curved screens

Photo: Lipsbaterando — CC BY-SA 4.0 (Wikimedia Commons)

⚠️ OLED and office work: beware burn-in. A taskbar, icons and toolbars sitting in the same place all day every day is the riskiest possible usage pattern for OLED. If this will be your main work monitor for eight hours a day, IPS is far safer.

Curved screens: the benefit is real only when the screen is wide enough that its edges are meaningfully further from your eyes, which means 34-inch ultrawide and up. On an ordinary 24–27 inch screen the curve does very little and has real drawbacks for design work and anything needing straight lines.

Choosing for your use

What people forget and end up buying afterwards

⚠️ A stand with no height adjustment is the most common problem with budget monitors. The top of the screen should be at or slightly below eye level, and if it cannot be raised you will bend your neck all day — which translates into real load on the cervical spine (see office syndrome). Check for VESA support so you can fit a separate stand or arm.

The ports supplied — many monitors provide HDMI but cap it at 60Hz for some resolutions. For 144Hz at 1440p you want DisplayPort or HDMI 2.1, and for a single-cable laptop connection look for USB-C with power delivery.

The cable in the box — often a basic one that does not support the monitor's top resolution or refresh rate, which is why people buy a 144Hz monitor and unknowingly run it at 60. Check in your display settings that you are getting what you paid for.

Real-world brightness — Thai rooms are often bright. If the screen faces a window, prefer a model bright enough and with a matte rather than glossy finish, which reflects everything.

Common mistakes

Buying 27-inch 1080p because it is big and cheap — visibly coarser than a 24-inch at a similar price.

Buying 4K at 27 inches expecting more workspace — you scale it back to 1440p's area.

Buying a refresh rate your graphics card cannot feed — paying for a number you never reach.

Not enabling the high refresh rate after installing — Windows very often defaults to 60Hz.

Ignoring monitor height — ending up buying a stand anyway, or with a sore neck every day.

Buying a curved 27-inch — paying extra for a benefit that barely exists at that size.

Using OLED as a main work monitor without considering burn-in from a static taskbar.

Summary

1. PPI = √(width² + height²) ÷ inches — you can work it out yourself.
2. 24" 1080p and 32" 1440p are equally sharp at 91.8 PPI — bigger is not sharper.
3. 27" 1080p at 81.6 PPI is the pairing to avoid, despite being the best seller.
4. 27" 1440p at 108.8 PPI is the sweet spot — 78% more area than 1080p.
5. 4K at 27" buys sharpness, not space, because you scale it back.
6. 60 → 144Hz is the valuable step; 240Hz and beyond is for competitive play.
7. Check VESA support and ports before buying — the two things that lead to extra purchases.

Sources

• Wikipedia — Pixel density (PPI)
• Wikipedia — Refresh rate
• Wikipedia — IPS panel
• VESA — DisplayPort standards

PPI values are calculated with the standard formula from the stated resolutions and diagonals, which is verifiable geometry. Whether that reads as "crisp" or "coarse" depends on your viewing distance and eyesight — open a page of small text on the actual screen at the distance you will use it before deciding.