Henley Passport Index

The Henley Passport Index (HPI) is a global ranking of countries according to the travel freedom of holders of their ordinary - as opposed to diplomatic - passport holders. It started in 2006 as Henley & Partners Visa Restrictions Index (HVRI) and was modified and renamed in January 2018. The site provides a ranking for 199 passports of the world according to the number of countries their holders can travel to visa-free. The number of countries that a specific passport can access becomes its visa-free 'score'. In collaboration with the International Air Transport Association (IATA), and based on official data from their global database Henley & Partners has analysed the visa regulations of the vast majority of the countries and territories in the world since 2006.
Definition of the Index.
The Henley Passport index (HPI) ranks passports according to how many destinations can be reached using a particular country's ordinary passport without requiring a visa ('visa-free'). All distinct destination countries and territories in the IATA database are considered. However, since not all territories issue passports, there are far fewer passports ranked than destinations against which queries are made.
Methodology.
To determine the score for each country or territory, its passport is checked against the IATA database in several steps:
1. Each of the 199 passports on the list, is checked against all 227 possible travel destinations for which travel restriction information exists in the IATA database. The score is updated throughout the year as conditions change.
2. Each query must satisfy certain conditions:
3. Further conditions include:
It is assumed that the visa policies of Greenland and the Faroe Islands are identical to Denmark.
4. If no visa is required for passport holders from a particular country or territory to enter the destination, then that passport scores 1. [The passport also scores 1 if a visa on arrival, a visitor's permit, or an electronic travel authority (ETA) can be obtained because they do not require pre-departure government approval, perhaps because of specific visa-waiver programs in place.]
5. Where visas are needed, or where passport holders have to get government-approved electronic visas (e-Visas) before departure, a score of 0 is given. If passport holders must get government approval before leaving in order to obtain a visa on arrival, this also scores 0.
6. The score for each particular passport is then totalled by adding up its scores for all destinations.
April 2021 results.
As of 2021, a Japanese passport offers its holders visa-free or visa-on-arrival access to a total of 193 countries, a Singapore passport offers its holders 192 countries, and South Korean passport and German passports each offer 191 visa-free or visa-on-arrival countries to their holders. An Afghan passport has once again been labelled by the index as the least powerful passport in the world, with its nationals only able to visit 26 destinations visa-free.
2006–2015.
European countries are notable for their stability over the past decade, and Belgium, France, Italy, Luxembourg, Spain, and Sweden all remain in exactly the same position as 10 years before. The 'Top 10s' were almost identical, with 30 countries in 2015, compared to 26 a decade before. While Liechtenstein dropped, the Czech Republic, Finland, Hungary, Malta, Slovakia, and South Korea all made it into the top 10.
Taiwan, Albania, the United Arab Emirates, Bosnia and Hercegovina, and Serbia all moved up more than 20 places in the Henley & Partners Visa Restrictions Index over the period, while the biggest drops were experienced by Guinea (−32), Liberia (−33), Sierra Leone (−35), and Bolivia (−37).
Older rankings.
In the table below, the "access" columns denote the number of visa-free destinations for holders of that passport. 
Unless indicated otherwise, the data in this table is taken from these sources. 