1. Why “the age of adulthood” is not one number
The question “how old is an adult?” has several answers. The age at which you can sign a contract without a parent’s consent (the civil age of majority), the age at which you can vote, the age at which you can buy alcohol or tobacco, the age at which you can marry, and the age of full criminal responsibility are written in different laws, and each country set them at different times and for different reasons. So “adults in Japan are 18” and “drinking in Japan starts at 20” are both true.
This article starts from the international baseline of 18 and then reads, from official sources, the countries that recently moved that line (Japan, Korea), the countries that lowered only the voting age (Austria, Scotland, the UK), and the country where the voting and drinking ages sit three years apart (the United States). Placed side by side, the five cases show that “the age of majority” is not a biological fact but a political decision each society has made.
2. The international baseline of 18: Article 1 of the UN Convention on the Rights of the Child
According to the United Nations Treaty Collection, the Convention on the Rights of the Child was adopted in New York on 20 November 1989 and entered into force on 2 September 1990 “in accordance with article 49(1)”; as of 6 September 2026 it lists 140 signatories and 196 parties. Article 1 defines a child as “every human being below the age of eighteen years unless under the law applicable to the child, majority is attained earlier.”
That single sentence is the key to reading ages of majority around the world. The international standard presents 18 as the ceiling, but it leaves each state room to set an earlier age of majority. Conversely, it does not prohibit an age of majority later than 18. What the convention fixes is the minimum line that “anyone under 18 must be protected as a child,” not a single age of adulthood. That is why 20 (Japan in the past), 19 (Korea), and 18 (most countries) all coexist under this convention.
3. Japan: from 20 to 18 after 140 years, but alcohol stays at 20
Japan’s Ministry of Justice explains in English that “a law was enacted to revise a part of the Civil Code by reducing the age of majority in the Civil Code from 20 to 18 years old,” and that “this age had been stipulated as 20 years old since the Civil Code was established in 1896.” The revised code took effect on 1 April 2022. The government’s public-relations site adds that the age of majority had been 20 “for about 140 years since the Meiji era,” and that people who were 18 or 19 on the effective date became adults on 1 April 2022. Majority is the age at which a person can “conclude a contract without parental consent” and “is no longer subject to parental authority.” The same reform raised the minimum marriage age for women from 16 to 18, making it 18 for both sexes.
Not every age moved, however. The ministry’s dedicated site on the reform stresses that even though the voting age and the age of majority are now 18, drinking alcohol “remains permitted only from age 20, as before,” that tobacco “likewise stays at 20,” and that buying tickets for public betting such as horse and boat racing also keeps its 20-year limit. The reason given is not contractual judgment but “effects on the health of young people” and the prevention of addiction. Japan is now a country where adulthood begins at 18 and drinking at 20.
4. Korea: 1 July 2013, from 20 to 19
Korea started from the same 20 as Japan and arrived at a different number. A notice from the Consulate General of the Republic of Korea in Nagoya records that “the revised Civil Code took effect on 1 July 2013. Under Article 4 of the revised code, the age of majority changed from the former 20 to 19,” and explains the result: “This means that at 19 a person becomes an adult rather than a minor. Accordingly, parental authority also ends once a person turns 19.”
With many countries choosing 18, Korea’s 19 is a striking choice. By lowering the age by just one year instead of going all the way to 18, Korea stands between the international baseline of 18 and the old East Asian standard of 20. When the age of majority changes, so do contracts, parental authority, and every procedure that requires a legal representative’s consent; the consulate’s explanation that children aged 19 or over are no longer treated as minor children in consensual divorce proceedings is one example of that chain reaction.
5. Austria: the 2007 law that gave 16-year-olds the vote in every election
The voting age can move independently of the age of majority. The Austrian Parliament’s election FAQ explains that under the 2007 electoral reform (Federal Law Gazette I No. 28/2007), “all Austrian citizens who have reached the age of 16 are eligible to vote in” National Council elections, Federal Presidential elections, European Parliament elections, provincial diet elections, local council elections (and mayoral elections where they exist), as well as referendums, popular initiatives, and plebiscites. In the same reform “the age of eligibility was lowered from 19 to 18” for candidates, while “only for Federal Presidential elections does it remain 35 years.” The constitutional changes were enacted through Federal Law Gazette I No. 27/2007, and the provinces adapted their own electoral rules to match.
Austria shows that “the age you vote” and “the age you sign contracts” can be separated. A 16-year-old is not an adult under Austrian civil law, but elects the president. The same separation reappears in the United Kingdom.
6. The United Kingdom: from Scotland in 2015 to the whole UK in 2025–26
The UK is a case where the voting age split by region inside one country. The Scottish Elections (Reduction of Voting Age) Act 2015, as published on legislation.gov.uk, is “an Act of the Scottish Parliament to reduce the voting age to 16 at elections for membership of the Scottish Parliament and local government elections”; the bill “was passed by the Parliament on 18th June 2015 and received Royal Assent on 24th July 2015.” The voting age for UK general elections at Westminster, meanwhile, stayed at 18.
On 17 July 2025 the UK government announced in a press release that “sixteen year olds will be given the right to vote in all UK elections,” describing the change as one that “will bring UK-wide elections in line with Scotland and Wales” and as “the biggest change to UK democracy in a generation.” The Representation of the People Bill that carries the change underwent scrutiny in the House of Commons in 2026; its commencement date and detailed rules will be fixed only when the legislative process is complete. The UK is thus changing its voting age by having Scotland choose 16 first and the whole country follow a decade later.
7. The United States: vote at 18, buy alcohol at 21
The United States has the widest gap inside one country. Section 1 of the 26th Amendment provides that “the right of citizens of the United States, who are eighteen years of age or older, to vote shall not be denied or abridged by the United States or by any State on account of age.” According to the National Constitution Center, Congress approved the amendment on 23 March 1971 and the states completed ratification on 1 July 1971, a little over three months later. The Richard Nixon Presidential Library records that President Nixon signed the certification on 5 July 1971 in the White House East Room, and explains that the slogan “Old enough to fight, old enough to vote” first arose during the Second World War, when the draft age was lowered to 18, and regained force during the Vietnam War.
Alcohol is another matter. Section 158 of Title 23 of the United States Code (National minimum drinking age) provides that part of the federal highway apportionment be withheld from any state “in which the purchase or public possession … of any alcoholic beverage by a person who is less than twenty-one years of age is lawful.” The share withheld was “10 per centum” before fiscal year 2012 and “8 percent” from fiscal year 2012 onward. The provision was added on 17 July 1984 by Public Law 98-363. Because the federal government steered the states with budget money instead of setting their drinking ages directly, the United States became a country where you vote and serve in the military at 18 but cannot buy alcohol until 21. That is why Japan’s Ministry of Justice guidance notes that “in the United States, too, the age of majority and the drinking age differ.”
8. What the five countries show together
First, ages of adulthood are trending downward, but they do not all move in one direction. Japan went from 20 to 18, Korea from 20 to 19, and Austria, Scotland, and the UK cut the voting age from 18 to 16. Yet the US drinking age and Japan’s drinking and smoking ages remain at 21 and 20 respectively, untouched by those reductions in the age of majority. The ages that fall are the ages of contracts and ballots; the ages justified by health and addiction rarely move.
Second, each age is set by a separate law. The UN’s 18 is a ceiling and a minimum line of protection, and beneath it each country writes different numbers into its civil code, election law, and liquor law. What a traveler or exchange student needs to check in a new country is not one “adult age” but a table of ages, one for each thing they want to do.
Third, all of these numbers carry dates: 1896; 1 July 1971; 17 July 1984; 2007; 1 July 2013; 24 July 2015; 1 April 2022; 17 July 2025. The age at which a person becomes an adult was not fixed by nature but by a parliament that voted in a particular year, and the next vote can change it again.