Diamond Valuation Calculator

Why Does the Calculator Show a Range Instead of One Exact Price?

A diamond does not have one universally fixed value. A retailer, insurer, auction house and professional diamond buyer may each be answering a different financial question.

Even when a grading report is available, two diamonds with similar headline grades can differ in measurements, proportions, inclusion placement, fluorescence, condition and overall marketability. Buyer demand also changes over time.

A range communicates this uncertainty more honestly than a precise-looking figure generated before the diamond has been examined. The narrower and more reliable estimate comes after the supplied details have been verified.

The result should therefore be presented as a preliminary resale estimate, never as a certified appraisal, guaranteed price or binding offer.

How the Diamond Valuation Calculator Works

The calculator begins with recognised grading characteristics, but it must go beyond simply multiplying carat weight by a fixed price.

One metric carat equals 200 milligrams, but carat measures weight rather than visual size. Diamonds close to significant weights such as 1.00, 1.50 and 2.00 carats may also enter different pricing categories because larger diamonds are rarer.

Natural or Laboratory-Grown Origin

Natural and laboratory-grown diamonds are genuine diamonds, but they belong to different resale markets. An owner may not be able to identify the origin visually, which is why an “I am not sure” option is necessary.

If origin is unknown, the calculator should request professional testing instead of assuming the diamond is natural.

Carat Weight and Measurements

Carat is an important value factor, but two diamonds of the same weight can appear different in size. A deep stone may carry more of its weight below the setting, while a well-proportioned diamond may have a larger face-up appearance.

Measurements also help an expert compare the entered information with the grading report and the physical stone.

Colour, Clarity and Cut

Colour and clarity grades can change the market category into which a diamond falls. The position and nature of an inclusion can also matter in ways that a simple dropdown cannot fully capture.

Cut quality, proportions, polish and symmetry influence appearance and buyer demand. These factors should be considered together rather than treated as unrelated scores.

Shape and Current Demand

Round, oval, emerald, cushion and other shapes do not always trade at the same price. Availability and buyer demand for a particular combination of shape, size and quality can affect the resale range.

Grading Report

A report from GIA, IGI or HRD Antwerp can make an online estimate more dependable because it provides independently assessed characteristics.

The report number should be verified through the issuing laboratory’s official database whenever possible. A report still does not guarantee the stone’s present condition or resale price because the diamond may have been damaged, altered or recut after the report was issued.

Illustrative Example: Two One-Carat Diamonds

Imagine that two sellers each enter a 1.00-carat round natural diamond into the calculator.

The first diamond has a verifiable grading report showing G colour, VS2 clarity and Excellent cut. The report also contains measurements, polish, symmetry and fluorescence information.

The second diamond is also described as one carat, but its exact colour and clarity are unknown. It remains mounted in an older ring and has no report.

The calculator can create a more defined preliminary range for the first stone because the seller has supplied standardised information. The second stone should not be described as worthless or automatically given a very low estimate. It should be directed to an expert review because its identity, weight and grades still need to be confirmed.

This is why a responsible calculator must treat “unknown” as a request for further examination—not as the lowest possible grade.

This is an illustrative example, not a Sothis customer case study.

Purchase Price, Insurance Value and Resale Value Are Different

If a diamond ring originally cost €8,000, it does not automatically have an €8,000 resale value. The purchase price may have included design, manufacturing, branding, retailer expenses, tax and retail margin.

An insurance appraisal usually estimates what it may cost to replace the jewellery through an appropriate retail channel. A resale valuation instead considers what the item could realistically achieve in the present secondary market.

An old receipt or appraisal can still provide useful background information. It simply answers a different question from the one a seller is asking today.

Can I Calculate My Diamond’s Value Without a Certificate?

Yes, you should still be able to begin. Many inherited or older diamonds no longer have their original paperwork.

Enter what you know and select “I am not sure” for the remaining fields. Photographs of the complete item, side profile, underside and visible hallmarks can help Sothis decide what type of inspection is required.

However, a photograph cannot reliably confirm exact colour, clarity, carat weight or natural origin. The result may therefore be a request for expert review rather than an immediate monetary range.

Do not pay for new certification before discussing the diamond with a professional buyer. Depending on the stone’s size, quality and likely market, the cost and time involved may or may not improve the selling outcome.

What If the Diamond Is Still in a Ring?

You do not need to remove it yourself. Attempting to loosen the prongs or push the diamond out of its setting could damage both the stone and the ring.

If the grading report shows the centre diamond’s carat weight and characteristics, enter those details. If the paperwork provides only a total carat weight for all stones, select “I am not sure” for the centre-stone weight.

During a professional examination, Sothis can consider the main diamond, smaller stones, precious metal, workmanship, condition and any brand-related value.

Illustrative Scenario: An Inherited Ring with Limited Information

Suppose you inherit a ring marked “18K,” but there is no receipt or grading report. A relative remembers that it was purchased many years ago, but no one knows the diamond’s weight or origin.

You select “diamond ring,” “origin unknown” and “carat weight unknown.” You then upload photographs of the ring from the front, side and underside, including the hallmark.

The calculator does not invent a price. Instead, it creates a valuation profile and asks for an expert review. After physical inspection, the centre stone and surrounding jewellery can be identified and considered separately.

The absence of paperwork creates a need for verification. It does not prove that the ring is valuable, but it also does not prove that it has no value.

This scenario is illustrative and should not be described as an actual customer transaction.

Why Might the Final Offer Differ from the Online Estimate?

An online calculator works with the information entered by the owner. If the carat weight, colour, clarity or origin is estimated incorrectly, the calculated range may change after inspection.

A physical review may also identify details the calculator cannot see, including:

• A chip near the girdle or underneath a prong
• A treatment not mentioned in the form
• A report that does not match the diamond
• Cloudiness or other condition concerns
• An incorrect total carat weight
• Valuable brand, period or workmanship details

The purpose of the estimate is to help you decide whether to continue—not to replace professional verification.

What Happens After I Calculate the Value?

Once your preliminary result appears, you can choose whether to request an expert-reviewed valuation.

Upload clear photographs and any available grading report. The Sothis team can review the information and advise whether the next step should be an Antwerp appointment or an agreed secure shipping process.

If the diamond proceeds to physical inspection, its characteristics, condition and paperwork can be verified before a final market-based offer is prepared. You remain free to accept or decline the offer.

Frequently Asked Questions

Is the diamond valuation calculator free?

Yes. The calculator is available without charge or an obligation to sell. If any additional laboratory or certification service could involve a fee, it should be explained and approved separately.

Does the calculator show retail or resale value?

This calculator is designed to indicate possible resale value for someone considering selling a diamond. It does not display a jewellery shop’s retail price or an insurance replacement value.

Is the calculator result a guaranteed offer?

No. The result is a preliminary range based on the information entered. A final offer may require photographs, report verification and physical inspection.

Can I use the calculator if I do not know the 4Cs?

Yes. Select “I am not sure” for unknown details and upload photographs if you want an initial expert review. The calculator should not force owners to guess grades.

Can the value be calculated from a photograph?

Photographs can help identify the item and its condition, but they cannot reliably confirm all grading characteristics. They support an initial review rather than a guaranteed monetary valuation.

Does a GIA report state what my diamond is worth?

No. GIA reports describe a diamond’s quality and identifying characteristics but do not provide an appraisal value or selling price.

Can I calculate the value of a laboratory-grown diamond?

Yes, but it must be assessed within the laboratory-grown resale market. Natural-diamond pricing must never be applied to a laboratory-grown stone.

Does the setting add value?

It may. Precious-metal weight, condition, workmanship, additional stones and recognised brand provenance can affect the value of the complete item.

Does fluorescence always reduce diamond value?

No. Its effect depends on the diamond and the strength and appearance of the fluorescence. It should not be handled through an automatic universal deduction.

What if my diamond has a chip?

You can still request a valuation. Select the possible-damage option and upload clear photographs. The location and severity of the damage need to be examined before its effect on value can be determined.

Can I use the calculator for fancy-coloured diamonds?

You can submit their information, but fancy-coloured diamonds should be routed to a specialist rather than priced with a standard D-to-Z diamond formula. Colour, intensity, overtone, origin and rarity require individual review.

Do I have to sell after receiving the result?

No. The calculator and initial review are intended to provide information. You decide whether you want to proceed after receiving the final offer.