Stamp Condition Value Estimator: What Faults Do to Price

There is no fixed percentage for any stamp fault, and our guides do not give one: the discount depends on the size and position of the fault and on how scarce the stamp is. On a common stamp a serious fault such as a tear or a thin can remove almost all of the value; on a genuinely scarce stamp the price falls, but the scarcity does not disappear. Tick what you see to get the typical effect, fault by fault.

Catalogues price a stamp in sound condition. A fault is never in the printed number, so every fault is a discount from it — and the worst fault on the stamp sets the tone of the price.

Each fault and its typical effect

Fault	Severity	Typical effect on price
Thin (bright patch against a light)	Serious	Common stamp: a small fraction of its sound price. Rare stamp: can still carry meaningful value.
Tear into the design	Severe	Almost always a small fraction of a sound copy.
Small tear or nick in the margin only	Moderate	Judged more leniently than a tear into the design.
Crease	Moderate	Moderate to serious depending on depth.
Toning or foxing (brown spots, staining)	Variable	Light toning is sometimes tolerated; foxing makes the stamp faulty.
Faded colour	Moderate	Below the same stamp with intact colour; heavy fading is discounted like damage.
Short or missing perforation teeth	Moderate	A listed fault: the stamp is no longer a sound copy.
Off-center, design still clear of the perforations	Variable	Grades below Superb; on classic material, Fine to Extremely Fine can multiply the price several times.
Badly off-center (design touches or is cut by the perforations)	Serious	Can be worth a small fraction of a well-centered copy.
Mint, but hinged	Moderate	A fraction of a never-hinged copy.
Disturbed, bloomed or regummed gum	Serious	A fraction of the quoted mint figure, sometimes less than a good used copy.

Each line summarises the linked StampWorth guide. None of the guides gives a fixed percentage, so neither does this tool.

Drawing of the back of a generic stamp in ordinary light, where it looks sound, and against a light, where a bright patch shows a thin — Illustration: a thin is often hard to see in ordinary light; held against a light it shows as a bright patch where paper is missing. Drawn diagram of a generic stamp, not a photo.

Drawing of a generic stamp with a tear running in from the perforations, and of a closed tear showing as a bright line against a light — Illustration: an open tear runs in from the perforated edge; a closed tear shows as a bright line when you hold the stamp against a light. Drawn diagram of a generic stamp, not a photo.

Drawing of a crease across a generic stamp casting a shadow under low side light, and showing as a darker line against a light — Illustration: under light from one low side a crease casts a thin shadow; against a light it shows as a line through the paper. Drawn diagram of a generic stamp, not a photo.

Drawing of a clean generic stamp next to one with toned, brownish paper and scattered brown foxing spots — Illustration: toning is a brownish tint to the paper; foxing is small brown spots, often on the margins and perforation tips. Drawn diagram of a generic stamp, not a photo.

Drawing of two copies of a generic stamp: full colour on the left, faded and paler in the centre on the right — Illustration: a faded copy is paler than one with its colour intact, and fading is often uneven, lightest where the light fell. Drawn diagram of a generic stamp, not a photo.

Illustration: every tooth should reach the same line; a short or missing tooth is a listed fault. Check each edge. Drawn diagram of a generic stamp, not a photo.

Drawing of a well-centered generic stamp with even margins next to an off-center copy whose design touches the perforations — Illustration: even margins on all four sides (left) against a design pushed into the perforations (right). Drawn diagram of a generic stamp, not a photo.

Drawing of the gummed backs of two generic mint stamps: one with a paper hinge remnant, one with patchy, disturbed gum — Illustration: a hinge remnant on the gum (left) and disturbed, patchy gum with an old hinge mark (right). Drawn diagram of a generic stamp, not a photo.

How the estimator works

Each fault is rated from the wording of its guide: variable (sometimes tolerated), moderate, serious or severe.
The most serious fault you tick sets the overall result, because a buyer prices the stamp from its worst fault.
The scarcity choice changes the wording: a fault on a common stamp can remove almost all of the value, while a genuinely scarce stamp keeps some value even when damaged.
Ticking more than one fault adds a note that they add up; the tool does not multiply invented percentages together.

Before you do anything to a damaged stamp, read its guide: a filled thin is still a repair, and added colour counts as an alteration. To see how the faults add up to a grade, read stamp condition and grading, or go back to all condition faults.

Common questions

How much does a thin reduce a stamp’s value?

There is no fixed percentage. A common stamp with a thin can drop to a small fraction of its sound price, and may sell only in a bulk lot; a genuinely rare stamp with a thin can still carry meaningful value because so few copies exist.

Which stamp fault reduces value the most?

A tear into the design and a thin are the most serious: both are permanent damage to the paper. A badly off-center copy and disturbed or regummed gum on a mint stamp can also bring the price down to a fraction of a sound copy.

Does a hinge reduce the value of a mint stamp?

Yes. A hinged mint stamp is worth a fraction of a never-hinged copy of the same stamp, and one with disturbed or regummed gum can be worth less than a good used copy.

Why does the estimator not show a percentage of catalogue?

Because there is no reliable fixed figure. The discount depends on the size and position of the fault and on how scarce the stamp is, and our guides do not state a percentage, so the tool gives the typical effect in words instead of inventing a number.

Stamp condition value estimator

Condition value estimator

Typical effect on price

Each fault and its typical effect

How the estimator works

Common questions

Check a stamp’s condition in seconds