Diamond Table Percentage by Shape: Ideal Ranges Explained

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A diamond's table percentage is the width of its flat top facet compared with the widest point of the stone — and the ideal range depends entirely on shape. A round brilliant looks its best at 54–57%, while a step-cut emerald wants 62–66% to keep its hall-of-mirrors flash. Get it right and the stone reads bright and alive; stray outside the range for its shape and even a well-polished diamond can look glassy or dark.

Key takeaways

• Table percentage = table width ÷ average girdle diameter, printed on every report as a single number.
• There is no universal ideal table — the correct range shifts by shape, from 54% for round brilliants to 66% for emerald and radiant.
• Table works together with depth percentage; read both, never one in isolation.
• A generic "50–60% is ideal" rule found online was written for round brilliants only.
• Montare holds a tighter window than the broad industry bands, shape by shape, verified against the IGI report.

What is a diamond's table percentage?

Look straight down at a diamond and the large flat facet in the middle is the table — the window light passes through on its way into the stone and back out to your eye. The table percentage is that facet's width divided by the diamond's average girdle diameter, expressed as a percentage. A report reading "Table: 56%" means the table spans 56% of the stone's total width.

It sounds like a minor specification next to carat weight or colour, but it is one of the few numbers that directly governs how a diamond performs optically — which is why laboratories assess it as part of overall cut quality alongside depth percentage, crown angle, pavilion angle, polish and symmetry.

Why table percentage matters more than you would think

Table size controls the balance between the two things a diamond does with light: brilliance, the white light bouncing straight back at you, and fire, the flashes of spectral colour. Those two come from different parts of the stone. Light returning through a large flat table reads as brightness; light refracted through the angled crown facets around it reads as fire.

So a larger table admits more light and produces a bigger, brighter face-up flash — but it does so by shrinking the crown facets that generate fire, and the stone can start to look glassy and one-dimensional. Too small a table and the aperture shrinks: less light enters, and the stone can read dark through the middle despite being technically well cut. The right table percentage is the point where a given shape's facet structure produces maximum brightness without surrendering fire, and that point differs for every shape because every shape distributes its facets differently.

Ideal table percentage by shape

These are the ranges Montare holds for the seven shapes we cut. Every stone is checked against its IGI report before it is approved for a setting.

Shape	Ideal table %	Why this range	Common mistake
Round	54–57	The most studied facet pattern in gemology; the optics are tightly solved	Accepting 58–60% because a generic guide allowed it
Oval	54–58	Brilliant faceting behaves like a round, stretched along one axis	Applying step-cut figures to a brilliant cut
Cushion	60–62	Keeps an elongated cushion crisp rather than soft and pillowy	Assuming cushions tolerate anything up to 68%
Emerald	62–66	Step cuts need a wide table for the hall-of-mirrors effect to work	Treating a low table as "safer" — it looks flat
Radiant	62–66	Brilliant faceting inside a cut-corner outline; behaves closer to emerald	Grading it against round-brilliant figures
Pear	54–58	Brilliant faceting; table placement balances point and rounded end	Ignoring how table interacts with the bow-tie
Marquise	54–58	A slimmer table reads as more brilliant along an elongated outline	Over-large tables that flatten the length

For depth percentage alongside these figures, see depth percentage by shape. For both numbers together with length-to-width ratios and face-up spread at three carats, the full reference is ideal cut, table and depth explained.

Why our window is tighter than the published bands

Search for cushion table percentages and you will find bands as wide as 61–68% presented as excellent. Ours is 60–62%. That is not a disagreement about optics; it is a narrower product decision, and it is worth being explicit about the reasoning rather than implying the wider figures are wrong.

Two things drive it. First, we only cut elongated cushions — length-to-width 1.25–1.35, never square — and an elongated outline reads crisper with a more contained table. Second, a wide published band is written to describe every acceptable stone in a market; a house standard only has to describe the stones we are willing to set. A range that spans seven percentage points is a description. A range that spans two is a decision.

The same logic applies across the table. Where a broad band exists, we sit in the part of it that favours a bright, contained face-up look at three carats and above, which is the size we actually sell.

Table percentage myths worth clearing up

"A bigger table means a bigger-looking diamond." Not quite. Table percentage is a ratio, not a size — a one-carat and a three-carat round can share an identical 56% table and look proportionally the same at different scales. What actually makes a stone look large for its weight is a good spread relative to carat weight, which comes from total depth, not table.

"One ideal range fits every diamond." This is the most common mistake buyers make: reading a general "50–60% is ideal" rule online and applying it to a fancy shape. That rule describes round brilliants. A radiant with a 56% table is not a better-cut stone — it is likely under-tabled for its facet structure.

"A high table percentage is a red flag." Only outside the range for that shape. A 65% table is a genuine problem on a round brilliant and sits comfortably mid-range on an emerald. Context — meaning shape — always comes first.

Table vs depth: how they work together

Table and depth are assessed together because they trade off against each other. A large table with a shallow pavilion can look bigger face-up per carat while losing fire. A smaller table with a deeper pavilion concentrates fire but can appear smaller for its weight, or go dark through the middle if pushed too far.

One failure mode worth naming properly, because it is often described loosely: a fish-eye is a whitish ring visible through the table, caused by the girdle reflecting back at you when the pavilion is cut too shallow. It is a depth problem that becomes visible through a large table — which is exactly why the two numbers are read as a pair rather than judged separately.

How to check table percentage on a certificate

Every IGI report lists "Table" as a percentage in the proportions section, next to depth percentage and the millimetre measurements. Most reports also carry a proportions diagram — a side-view sketch marking crown angle, pavilion depth and girdle thickness — worth a glance alongside the raw numbers. Compare the figure against the range for that specific shape, never a generic rule of thumb.

Two changes in the grading landscape are worth knowing when you read one. AGS Laboratories closed at the end of 2022 and merged into GIA, so an AGS report is a historical document rather than a current one; its cut-grade methodology survives as a supplement to GIA reports. And since 1 October 2025, GIA no longer issues specific colour and clarity grades on lab-grown diamonds, using a two-tier Premium or Standard classification instead — proportions are still measured, but the surrounding grades are less granular. IGI continues to grade lab-grown on the full 4Cs. We compare the two in IGI vs GIA for lab-grown diamonds, and walk through a full report in how to read a diamond certificate.

What about princess, Asscher and heart shapes?

They have their own ideal table ranges — princess and Asscher sit considerably higher than a round brilliant, in the high 60s to low 70s — but they are not part of the Montare lineup, so we do not publish house figures for them. We cut seven shapes: round, oval, elongated cushion, emerald, elongated radiant, pear and marquise. That is a deliberate narrowing rather than an oversight; holding a fixed standard across a smaller range is what makes the standard meaningful. See the full set in our visual guide to diamond shapes.

The Montare standard

Every diamond Montare sets is lab-grown, D–E colour, VVS1–VVS2 clarity, Triple Excellent cut, cut to ideal table and depth for its shape, three carats minimum and IGI certified. We do not buy loose stones on carat weight and hope the proportions work out — every stone is checked against its report before approval, table and depth included.

It is worth noting that a Triple Excellent grade alone does not guarantee an ideal table: the Excellent band is broader than the ideal window, which is why we apply the proportions check as a separate condition. More on that in Triple Excellent cut explained, with the full standard on our standards page. Start designing on the ring builder.

Frequently asked questions

What is a good table percentage for a diamond?

It depends entirely on the shape. Round brilliants look best at 54–57%, ovals, pears and marquise at 54–58%, elongated cushions at 60–62%, and emerald and radiant cuts at 62–66%. There is no single good number that applies across all shapes.

Is table percentage the same for every diamond shape?

No. It is one of the most shape-dependent numbers in diamond grading, because facet architecture differs by shape. Step cuts such as emerald need a much wider table than brilliant cuts to produce their characteristic flash.

Does a bigger table make a diamond look bigger?

Not meaningfully. Table percentage is a ratio rather than a size. What makes a diamond look large for its weight is its spread relative to carat weight, which is governed by total depth — a stone cut too deep hides weight below the girdle and wears smaller.

Can a diamond have an Excellent cut grade with a table percentage outside the ideal range?

Yes. Cut is graded holistically, so table, depth, crown angle, pavilion angle, polish and symmetry all interact and a stone slightly outside one range can still earn Excellent if the others compensate. This is why Montare treats ideal proportions as a separate requirement on top of the grade.

What is a fish-eye diamond?

A fish-eye is a whitish ring visible through the table, created by the girdle reflecting back at the viewer when the pavilion is cut too shallow. It is caused by depth rather than table, but a large table makes it easier to see — which is why the two figures are read together.

Where do I find a diamond's table percentage?

In the proportions section of its IGI report, shown as a percentage alongside depth percentage and the stone's millimetre measurements, usually next to a proportions diagram of the stone in profile.

Does AGS still grade diamonds?

No. AGS Laboratories closed at the end of 2022 and merged into GIA, which acquired its technology and intellectual property. An AGS report is therefore a historical document, though the AGS cut-grade methodology continues as a supplement to GIA reports.

Does Montare only sell diamonds within the ideal table range?

Yes. Every Montare diamond must sit inside the ideal table and depth window for its specific shape as well as carrying a Triple Excellent grade, verified against its IGI report before the stone is approved for a setting.

Proportions checked, every stone. Build a ring in the ring builder or book a consultation.