What Is Delta E on a Monitor? Color Accuracy Guide (2026)

Explainer

Shamim Sarker
Founder & Editor · Monitors & Color Accuracy Guides

You’ve narrowed it down to two monitors. Both spec sheets promise “Delta E < 2.” Both say “factory calibrated.” One costs $250 more, and nothing on the listing tells you why.

That small ΔE number is supposed to settle the color-accuracy question. Often it doesn’t. Brands use different formulas, average different color sets, and rarely mention which picture mode they measured.

That gap can show up after you buy. Back in 2019, one Dell UltraSharp owner posted in Dell’s community forum that his “Delta-E less than 2” monitor had such uneven color across the screen that he sent it back for a refund and said he felt misled.

This guide explains what Delta E actually measures, which numbers are good, and how to read a spec sheet so the number works for you, not for the marketing team.

What Is Delta E on a Monitor? The Plain-English Definition

Before you can judge a Delta E number on a spec sheet, it helps to know exactly what’s being measured.

The International Commission on Illumination (CIE) defines color difference as the distance between two colors in a specified color space. If the screen hits the target exactly, Delta E is 0. The further off it lands, the higher the number climbs.

What Do the “Delta” and “E” Actually Stand For?

“Delta” is the Greek letter mathematicians use for a change or difference. The “E” comes from Empfindung, the German word for sensation, according to ViewSonic’s color guide.

How Does Delta E Work in CIELAB Color Space?

Delta E is calculated in a color space called CIELAB (often written L*a*b*). It places every color at a point defined by three coordinates, as ViewSonic’s guide lays out:

• L* is lightness, from 0 (black) to 100 (white).
• a* runs from green (negative) to red (positive).
• b* runs from blue (negative) to yellow (positive).

Delta E is the distance between the target point and the measured point. Here’s a simple example. Say the target is a neutral mid-gray (L* 50, a* 0, b* 0), but the monitor shows L* 50, a* 0, b* 2. That gray has drifted slightly toward yellow, and the basic formula gives a Delta E of 2.

Written out, that basic 1976 formula is ΔE*ab = √[(ΔL*)² + (Δa*)² + (Δb*)²], the straight-line distance between the two points.

Newer formulas weight that distance differently depending on the color, which is why the formula behind a spec matters. The formula section below explains why.

What Is a Good Delta E Value for a Monitor?

For color work, aim for an average Delta E below 2. Below 1 is excellent, 2 to 3 is fine for everyday use, and above 3 starts to look visibly off. Here’s how the ranges break down, compiled from guides by Kuycon, KTC, and ViewSonic.

Source tier: Third-Party Published. These ranges are widely used rules of thumb, and the cited guides don’t always specify a formula. Sensitivity varies by color, brightness, and viewing conditions.

Why Do Sources Disagree on 2 vs. 2.3 vs. 3?

Shop around and you’ll see different “good” numbers. BenQ calls ΔE 3 or lower the ideal range. ViewSonic sets the bar at 2. XPPen says anything below 2.3 is safe.

They aren’t really contradicting each other. They’re often measuring different things:

• Different formulas. The 2.3 figure is the classic “just noticeable difference” for the old CIE76 formula, as documented by the Colour Science for Python reference. The newer ΔE2000 formula produces different numbers for the same color error.
• Average vs. worst case. One brand may quote an average across many colors, another a maximum. Many spec sheets don’t say which.
• Different eyes. 3DTested notes the average person won’t notice errors below 3, while a trained eye can spot errors down to about 1.

Independent reviewers set their own pass lines too. German site Igor’s Lab, for example, uses an average below 2.5 and a maximum below 4.5 in its monitor tests.

Delta E Formulas Explained: CIE76 vs. CIE94 vs. CIEDE2000

The disagreement over thresholds points to a bigger issue: “Delta E” isn’t one formula. It’s a family of formulas, and each one scores the same color error a little differently.

The original 1976 formula simply measures the straight-line distance between two colors, as ViewSonic explains. The problem is that human vision isn’t equally sensitive to every color, so later versions added corrections to better match what people actually see.

Source tier: Third-Party Published, based on ViewSonic, KTC, and ITU-R BT.2124.

Why Isn’t ΔE 1 in One Formula the Same as ΔE 1 in Another?

Because each formula weighs errors differently, the same color mistake can produce two different Delta E numbers. KTC warns that a Delta E of 1 in one formula isn’t automatically comparable to a Delta E of 1 in another.

That’s why the formula label matters when you compare two monitors. Today, CIEDE2000 is formally standardized as ISO/CIE 11664-6:2022, and the widely cited implementation notes by Sharma, Wu, and Dalal document exactly how it’s calculated. It’s the version you should look for on a spec sheet or review. If a listing doesn’t name its formula, treat the number as a rough hint, not a promise.

Average vs. Maximum Delta E: The Number Spec Sheets Hide

A single Delta E figure is either an average or a worst case, and that difference decides how much the claim tells you.

To get a Delta E figure, a meter measures a set of color patches, often a few dozen. KTC points to one factory report built from a 39-color patch set. Each patch gets its own score, and those scores are then summarized.

• Average Delta E shows overall accuracy across all patches.
• Maximum Delta E shows the single worst color the monitor produced.

In our price-tier table below, all five manufacturer claims are a single number: three are labeled averages, two aren’t labeled at all, and none lists a maximum. A low average can hide one or two colors that are badly off. According to KTC’s guide for professionals, saturated reds, deep blues, and near-black grays are common trouble spots.

In the example above, a listing would honestly say “ΔE < 2.” Yet anyone editing a red product shot or a sunset would see the problem.

That’s why ViewSonic advises checking whether a spec refers to the average or the maximum. If you can find both numbers, trust the pair over either one alone. A calibration report or an independent review usually lists both.

Delta E vs. Color Gamut vs. Bit Depth

Delta E rarely appears on a spec sheet by itself. It usually sits next to gamut coverage and bit depth, and those three numbers get mixed up all the time.

Color gamut is the size of your paint box. Delta E is whether you dip the brush into the right color. Bit depth is how many fine steps of shading you get between two colors.

Kuycon’s guide puts it the same way: Delta E measures accuracy, gamut measures range, and bit depth measures tonal smoothness.

Source tier: Third-Party Published (Kuycon, CIE).

These specs don’t guarantee each other. HP notes that a monitor can cover 99% of Adobe RGB and still post a high Delta E if it isn’t calibrated properly.

The reverse happens too. A budget screen can be very accurate inside sRGB but simply unable to show the wider colors a photographer printing in Adobe RGB needs. You want both a gamut that fits your work and a low Delta E inside it. Our sRGB vs. DCI-P3 vs. Adobe RGB guide explains which color space fits which job, and our 8-bit vs. 10-bit monitor guide covers bit depth in more detail.

How Delta E Is Measured (and How to Read a Calibration Report)

Every Delta E number comes from a measuring device and a set of test patches, so it’s only as trustworthy as the way it was measured.

What’s the Difference Between a Colorimeter and a Spectrophotometer?

Delta E is measured with a small device that rests on the screen while software flashes a series of color patches. Most people use a colorimeter, which reads light through filters designed to mimic human vision, as ViewSonic describes.

A spectrophotometer measures the full light spectrum instead. Whitewall notes that high-quality spectrophotometers measure more accurately than basic colorimeters. ITPro, for example, pairs a colorimeter with the free DisplayCAL software in its monitor testing.

How Do You Read a Factory Calibration Report?

Many creator monitors ship with a printed report. Before you trust its headline number, check these lines, based on the checklists from Kuycon and BenQ:

1. Color space: sRGB, DCI-P3, Display P3, or Adobe RGB. Accuracy only counts against a named target.
2. Formula: ΔE2000 is the one you want.
3. Average and maximum: both numbers, not just one.
4. White point: usually D65 (about 6500K), which keeps whites neutral.
5. Gamma: usually 2.2 for standard work. It controls midtones and shadows.
6. Picture mode: which preset was measured. Accuracy in sRGB mode doesn’t carry over to a vivid gaming mode.

Can You Check Delta E Without a Colorimeter?

Not as a number. Your eyes adapt to the screen in front of you, so they can’t calculate an error score.

Test patterns and comparisons against a reference print can reveal big problems, like a green tint or crushed shadows. Lenovo notes this visual approach catches major issues but may miss subtle ones. For an actual Delta E value, you need a meter or a published review that used one.

Does Factory Calibration Last?

Not forever. Backlights and panels age, so colors slowly drift. ICC guidance suggests that roughly six-month intervals are often enough. Kuycon notes many professionals recalibrate quarterly.

What Delta E Should You Expect at Each Price Tier?

Most people shop by budget first, so here’s how Delta E claims and independent measurements line up across price tiers.

The short answer: “ΔE < 2” now shows up on monitors under $350. What you get by spending more is a wider gamut, tighter worst-case errors, and extras like hardware calibration. The table below pairs each maker’s claim with numbers independent reviewers actually measured.

Price bands are approximate and change often; check current pricing before you buy. Most reviews don’t state which Delta E formula they used unless noted, so treat cross-review comparisons as rough.

What Does the Gap Between Claimed and Measured Delta E Tell You?

For four of the five monitors, every published average matched or beat the brand’s claim. The PA278QV split: Guru3D measured 1.31 (using ΔE94), while Monitornerds measured 2.16. Digital Camera World called BenQ’s ≤ 1.5 promise for the SW272U conservative after measuring 1.07.

The maximum errors tell a different story. Even good monitors posted worst-case values between 2 and 4, which is right where a careful eye can spot a shift. Picture mode matters too: DisplayNinja found the PA279CRV’s default Native mode hit a maximum of 4.49, versus 2.04 in its sRGB preset.

Results also vary by unit and by test. RTINGS measured an average white balance dE of 5.58 on its U2725QE sample in sRGB mode, far from Expert Reviews’ results on a different unit. White balance error isn’t the same metric as color error, but it shows why one review is never the whole story.

One more reality check: Expert Reviews notes that many ordinary gaming monitors now post average Delta E figures under 1. A low average alone no longer marks a monitor as “pro.” Gamut, maximum error, and calibration tools are what separate the tiers.

Who Needs a Low Delta E (and Who Can Skip It)

The price-tier numbers raise an obvious question: do you actually need to pay for that accuracy? It depends almost entirely on what you do with your screen.

Who Should Pay for Low Delta E?

Who Can Skip Paying for Low Delta E?

If you’re in the first group, the right Delta E target depends on where your work ends up. This breakdown is adapted from KTC’s workflow guide:

Source tier: Third-Party Published (KTC, TCL).

If a wrong color costs you money or a client, pay for low Delta E. If it doesn’t, spend that budget on refresh rate, resolution, or a better stand.

Spec-Sheet Red Flags: How to Spot Vague Delta E Claims

Once you know your target, the last skill is reading listings with a skeptical eye. A Delta E claim is only as useful as the details behind it.

None of these flags means a monitor is bad. They mean the number on the box can’t answer your question yet, so look for a calibration report or an independent review before you buy.

What a trustworthy listing looks like: “Average ΔE2000 < 2 in sRGB mode, factory calibrated, report included.” It names the statistic, the formula, and the mode, and it points you to proof.

Bottom Line: How to Use Delta E When You Shop

References