Do I count holes or teeth?

Count teeth. Perforation gauges and standard practice count the number of teeth that fall within a fixed 2 cm span, not the holes between them.

What if edges are damaged or trimmed?

Measure on the best preserved straight edge. If damage prevents a reliable count, note the condition and try to use other features such as design, watermark, or a scan to help identify the stamp.

Can I identify a stamp from a scan?

Yes. A flat, high-resolution scan that clearly shows edges can be used to count teeth per 2 cm and compare other features. Use a scanner setting that preserves sharpness around the perforations.

How to identify a stamp by its perforation count

Perforation count is a simple, repeatable physical feature you can use to identify and compare stamps when you collect or research postage. This guide explains what to look for and how to measure accurately.

Quick facts

Perforation gauge: teeth per 2 cm
Imperforate stamps: no teeth

Why perforation matters

Perforation is the row of small separations along a stamp edge that let stamps tear apart. Perforation gauge: teeth per 2 cm. The count is used in philately to narrow a stamp's identity and can affect the stamp's value in catalogs. Some stamps have no perforations at all; Imperforate stamps: no teeth.

Tools you need

Work on a flat surface with good light. Useful tools: a perforation gauge (rules are scaled in teeth per 2 cm), a small magnifier, tweezers, and a scanner if you will keep a digital record. A simple ruler marked in millimetres will do if you do not have a dedicated gauge.

How to count perforations step by step

1) Place the stamp face down so the perforations show clearly. 2) Choose a straight section of edge, typically the top or bottom. 3) Line up a perforation gauge or a 2 cm span on your ruler so that the span covers a clear set of perforation teeth. 4) Count the number of teeth that fall within that 2 cm span. The perforation gauge measures teeth per 2 cm, so your count across that exact 2 cm gives the number you need. If the stamp has no perforations at all, record it as imperforate: Imperforate stamps: no teeth.

Special cases and tips

Corners, trimmed edges, or damaged teeth make counts unreliable; always measure on an undamaged, straight edge. Some stamps have different perforation counts on different edges; record counts for each side if they vary. For very small or worn teeth use a magnifier. When you scan a stamp, ensure the image is flat and at high resolution before attempting to measure from the image; a scanner can help create a repeatable digital record for later comparison.

When you want faster identification

After you learn to count perforations, you can combine that count with other features — design, watermarks, colour, and country — to identify a stamp. If you want a workflow that includes scanning and an automated identifier, try the Stamp Identifier tool to scan stamps and match perforation counts with catalog entries.

Common questions

Do I count holes or teeth?: Count teeth. Perforation gauges and standard practice count the number of teeth that fall within a fixed 2 cm span, not the holes between them.
What if edges are damaged or trimmed?: Measure on the best preserved straight edge. If damage prevents a reliable count, note the condition and try to use other features such as design, watermark, or a scan to help identify the stamp.
Can I identify a stamp from a scan?: Yes. A flat, high-resolution scan that clearly shows edges can be used to count teeth per 2 cm and compare other features. Use a scanner setting that preserves sharpness around the perforations.

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