rank_per_million,mensa,country,members_used,members_used_from,per_million,population_2025,own_site,own_as_of,own_source,mensa_international_page,mi_page_updated,mi_source,note
13,American Mensa,United States,40000,own site,117.0,341784857,"more than 40,000",,https://www.us.mensa.org/learn/about/,"around 42,000",2026-01-09,https://www.mensa.org/usa/,"Mensa International's About page says ""nearly 50,000""."
10,Mensa Germany,Germany,20000,own site,239.5,83491249,"more than 20,000",,https://www.mensa.de/about/,"around 17,700",2026-04-23,https://www.mensa.org/germany/,
11,British Mensa,United Kingdom and Ireland,17000,own site,226.8,74971367,"around 17,000",,,"more than 17,000",2026-04-23,https://www.mensa.org/britishmensa/,
1,Mensa Sweden,Sweden,8000,own site,755.0,10596620,"over 8,000",,https://mensa.se/om-mensa/det-har-ar-mensa/,,,,Mensa Sweden says Sweden has the highest share of members of any country.
20,Japan Mensa,Japan,7000,own site,56.7,123366734,"more than 7,000",end of March 2025,https://mensa.jp/about.html,"around 5,900",2026-04-23,https://www.mensa.org/japan/,
4,Mensa Czech Republic,Czechia,6400,own site,587.9,10886878,"6,400",,https://mensa.cz/o-mense/,,,,"1,800 of the 6,400 are members of Children's Mensa."
5,Mensa HungarIQa,Hungary,5529,own site,581.1,9514251,"5,529",,https://mensa.hu/,,,,
19,Mensa France,France,4565,own site,66.4,68720337,"4,565",,https://www.mensa.fr/,"around 4,700",2026-04-23,https://www.mensa.org/france/,
2,Mensa Singapore,Singapore,4000,Mensa International,654.5,6111175,,,,"around 4,000",2026-04-23,https://www.mensa.org/singapore/,
3,Mensa Finland,Finland,3500,own site,619.9,5646436,"over 3,500",,https://www.mensa.fi/toiminta/,,,,
18,Mensa Spain,Spain,3500,own site,70.9,49355143,"more than 3,500",January 2026,https://mensa.es/informacion/que-es-mensa/,,,,
14,Australian Mensa,Australia,3200,own site,115.9,27614411,"3,200",2026,https://www.mensa.org.au/about-us/our-association,"around 3,143",2026-06-01,https://www.mensa.org/australian-mensa/,Australian Mensa says over 40% of its members are under 18.
6,Mensa Norway,Norway,3000,own site,534.7,5610870,"around 3,000",end of 2025,https://mensa.no/mensa/,"around 2,600",2026-04-23,https://www.mensa.org/norway/,
17,Mensa Poland,Poland,2700,own site,74.1,36435861,"2,700",,https://www.mensa.org.pl/,,,,
21,Mensa Italy,Italy,2500,own site,42.4,58915656,"over 2,500",,https://www.mensa.it/,"around 2,600",2026-04-23,https://www.mensa.org/italy/,
25,Mensa Brazil,Brazil,2200,Mensa International,10.3,212812405,,,,"around 2,200",2026-04-23,https://www.mensa.org/brazil/,
9,Mensa Denmark,Denmark,2100,own site,349.5,6009169,"over 2,100",,https://mensa.dk/om-mensa/hvad-er-mensa,,,,
27,Mensa India,India,2000,Mensa International,1.4,1463865525,,,,"around 2,000",2026-04-24,https://www.mensa.org/india/,
8,Mensa Croatia,Croatia,1445,own site,372.8,3876200,"1,445",end of 2025,https://mensa.hr/o-mensi.html,"around 1,200",2026-04-23,https://www.mensa.org/croatia/,
15,Mensa Greece,Greece,1200,own site,115.2,10413962,"over 1,200 active",,https://www.mensa.org.gr/mensa/about,"around 1,260",2026-04-23,https://www.mensa.org/greece/,
23,Malaysian Mensa,Malaysia,800,Mensa International,22.2,35977838,,,,around 800,2026-06-22,https://www.mensa.org/malaysian-mensa/,
16,Mensa Hong Kong,Hong Kong,600,own site,80.0,7498900,more than 600,,https://www.mensa.org.hk/faqs,around 630,2026-04-23,https://www.mensa.org/hong-kong/,"Its About page says membership ""has steadily increased to more than 3,400""."
22,Mensa Romania,Romania,600,Mensa International,31.5,19020271,,,,around 600,2026-05-12,https://www.mensa.org/romania/,
24,Mensa Argentina,Argentina,520,Mensa International,11.3,45851378,,,,around 520,2025-02-17,https://www.mensa.org/argentina/,
26,Mensa Mexico,Mexico,400,Mensa International,3.0,131946900,,,,around 400,2026-04-23,https://www.mensa.org/mexico/,
12,Mensa Slovenia,Slovenia,300,own site,140.8,2130986,almost 300,,https://mensa.si/,around 400,2026-06-01,https://www.mensa.org/slovenia/,
7,Mensa Montenegro,Montenegro,290,Mensa International,465.4,623129,,,,around 290,2026-04-23,https://www.mensa.org/montenegro/,
,Mensa Netherlands,Netherlands,4500,own site,248.8,18087633,"just over 4,500",end of 2014,https://www.mensa.nl/veelgestelde-vragen,,,,"The only figure it publishes is from 2014, so it is not ranked."