✅ Topical Collection Completion Calculator
Enter how many stamps you own in a topical or thematic set (birds, ships, space, etc.) and the full set size to see your completion percentage.
How completion is worked out
Two figures come out of the same pair of inputs - the percentage held, and the count still missing:
completion = owned / set size x 100
remaining = set size - owned (never below 0)
40 / 120 x 100 = 33.3% remaining 80The percentage is shown to one decimal, so one more stamp in a 120-stamp topic moves you 0.8 points. Enter more than the set size and the figure passes 100 per cent while remaining stays at 0 - that is duplicates or varieties you are counting, not progress. An empty set-size box falls back to 1 and the percentage explodes.
Deciding what counts as the full set
Topicals have no official master list, so the denominator is a decision you make, not a fact you look up. Pin it down before you start counting:
- Scope. One country's bird issues is a different denominator from every bird stamp worldwide. Narrow scopes finish; global ones do not.
- Source. A thematic catalogue, an American Topical Association checklist or a handbook for the subject gives you a defensible number and a want list in the same pass.
- What a unit is. Decide whether a se-tenant strip counts as one item or four, and whether souvenir sheets and imperforate variants are in or out, then hold to it.
Frequently asked questions
What percentage is 40 out of 120 stamps?
33.3 per cent, with 80 still to find. Divide 40 by 120 and multiply by 100.
How do I find out how many stamps exist on a topic?
Thematic catalogues and society checklists are the practical sources. For a worldwide subject there is no fixed number, so most collectors fix a scope - one country, one decade, one catalogue's listing - and use that count.
Why does my completion read over 100 per cent?
You have entered more stamps than the set size. Either duplicates are in the owned count, or the set size is too low for the scope you are actually collecting.