How many Crown sized coins are in my collection?

With the help of a Numista referee, who guided me through the process of answering the above question, I came up with the following answers, using the search system.

Used diameter first.

38.61mm.  833 coins

38.60mm.  840 coins

38.60-38.62mm.  727 coins

38.55-38.65mm.  773 coins

Then decided to use weight

28.20-28.30grms.  493 coins

With the above variances being miles apart, I still have no idea of how many crown sized coins are in my collection.

Crown sized coins are listed as 38.60mm or 38.61mm diameter with a weight of 28.28grms.

Can anyone solve my enigma please

All the single diameter searches contain coins from 38.11-39.11 mm and 38.1-39.1 mm … that's why there are more hits than for the range searches. As you say that crown coins are 38.60mm or 38.61mm diameter with a weight of 28.28grms why are then only using one of them and not both of those values to find out?
 

Search query

Tried the following search using two criteria

38.55-38.65 diameter

28.10-28.60 weight

Result 476 coins

A lot of the crowns are entered to Numista based on Krauze catalogues which frequently say diameter 38.5mm (eg. IOM, Gibraltar), even the Pobjoy records say 38.60 for CuNi and 38.61 for silver proofs. What is more, there is always a weight tolerance and also the balance tolerance. I would suggest slightly increase the range, let's say 38.5-39mm and weight 28-28.60 or even more.

Anyway, when using these criterias in filters you skip the coins that are with missing weight or diameter entered.

If you want to check how many Crowns you have in your own collection, I would suggest export full collection(s) to Excel, activate filters and go though the list. You can use multiple filters separatly or at once (diameter, weight, denomination, title), add the number “1” in the last column if the filtered coins are really Crowns. Deselect coins once marked as Crowns and repeat your filtering changing criterias (bigger tolerance od weight or diameter) till the moment you are sure no more coins are Crowns. Etc. Then remove all filters and simply count how many “1” you have in last column. That 's my idea how to count all.

Just used 38.50-39.00 and 28.00-28.60 as recommended.

Result-652 coins

I thought this was going to be a very simple task, but not so.

I do not want to download 16,500 coins and then filter, as I thought the Numista system did that for me

Greetings.  It depends on what your (or someone else's) definition of what a crown sized coin is.  I've never seen a single internationally agreed upon standard.

Dr. John S. Davenport wrote many books on crown sized coins and I believe his definition was silver coins with a diameter greater than 38 mm.  He wrote many books dedicated to crown sized coins from around the world.

This is the author I'm talking about and a listing of some of his books:  https://en.numista.com/people/john-stewart-davenport

I thought Crowns would also include any coin weighing 25 grams or more and 37mm or larger.

Those measurements, really just leave British crowns and German 5 Mark coins before 1915.

I have 33 Unique British crowns and about 40 more later ones, including silver proofs. NZ silver large dollars were also crown sized and so were some other coins like Jamaica $1 1969 and 1978, South African 5/- and 50 cent coins to 1964, Cyprus 1928 45 Piastres. In all I have about 150 Crowns.

Double that for coins between 24.5 and 28 grams like Dutch 2½ guilders, Latin Monetary Union 5 Units, Morgan and Peace Dollars and a few others.

Very good points.  Dr. Davenport does cover coins 37 mm as well.  I forgot about those.  On the other end of the spectrum, he also wrote several books on “oversized” Crown coins as well.   Yes, many Americans here would also include Morgan and Peace dollars as crown sized coins.  I've seen this topic come up a lot on coin forums on the internet.  Usually people start off the conversation with something along the lines of “And this is what I mean when I refer to a crown sized coin . . .”  There's no international standard.