Regnal Year Converter

How to Use the Regnal Year Converter

1. 1. Choose the direction. Convert a regnal year to dates, or a date to its regnal year.
2. 2. Enter the citation or the date. Write the regnal year as an Act or record gives it — 13 Cha. 2, 41 Geo. 3, 1 Will. & Mar., or 13 & 14 Cha. 2 for a session across two years. Write a date as 1661-01-30, 30 January 1661, or 30 January 1660/61.
3. 3. Say which calendar a date is in. The default reads dates as England wrote them: Julian before 14 September 1752 and Gregorian after. Choose Gregorian if you have already converted the date.
4. 4. Read the dates and the cautions. Each result shows the start and end of the regnal year as written at the time and in the Gregorian calendar, plus any special case that applies to that reign.

What a Regnal Year Is

Until 1963, Acts of Parliament were cited by the regnal year of the session in which they passed: the Crown Debts Act 1801 is 41 Geo. 3 c. 90. A regnal year runs from the anniversary of a monarch's accession to the day before the next one, so it straddles two calendar years and begins on a different day for every reign — 25 October for George III, 6 February for Elizabeth II, 17 November for Elizabeth I. The citation of Acts moved to calendar years after the Acts of Parliament Numbering and Citation Act 1962. From 8 September 2026 the current year is the fifth of Charles III, 5 Chas. 3.

Dates for the reigns since George III come from the UK Parliament's own table of regnal years (api.parliament.uk/regnal-years), and every year in that table is checked against this converter. Earlier reigns follow the standard reckoning in C R Cheney's Handbook of Dates, as reproduced in the New Zealand Law Foundation's style guide and cross-checked with other tables. Treat reigns before Henry III (1216) as reference points, because sources differ on the accession days.

Old Style and New Style Dates

England used the Julian calendar until the Calendar (New Style) Act 1750. In 1752 Wednesday 2 September was followed by Thursday 14 September, and the year began on 1 January instead of 25 March. Before that, a date from 1 January to 24 March belonged to the old year, so historians write 30 January 1660/61 for what we call January 1661. The converter reads and writes that double year, and shows the Gregorian equivalent of every Julian date — ten days later in the 1600s, eleven in the 1700s.

Reigns With Unusual Regnal Years

Regnal Year Examples

From a regnal year to dates

The 13th year of Charles II, which includes the Corporation Act 1661. The year is Old Style, so January falls in the old year 1660/61:

A session that crosses two regnal years is cited with both numbers. The Treason Act 1695 (7 & 8 Will. 3 c. 3) passed in a session that sat from November 1695 to April 1696, across the 7th and 8th years of William III:

The year of the Crown Debts Act 1801 (41 Geo. 3 c. 90), which OSCOLA gives as its example of a regnal citation. After 1752 there is no Old Style date to convert:

The year in which England changed calendar. The first day of 26 Geo. 2 is an Old Style date and the last is a New Style one, and the year is 365 days long:

Two years that run on from the Old Style calendar's quirks: the first year of William and Mary, and the first year of Philip and Mary, cited as a pair.

From a date to a regnal year

15 June 1215, the day King John sealed Magna Carta at Runnymede. John's years begin on Ascension Day, so the 17th year began on 28 May:

1 January 1600 was in the old year 1599, so it belongs to a regnal year that began in November 1599:

Citing a Regnal Year

Give the regnal year, the monarch's abbreviation and the chapter. legislation.gov.uk writes the abbreviation with full stops — 41 Geo. 3 c. 90 — and OSCOLA leaves them out, as in 41 Geo 3 c 90 (see the OSCOLA Citation Generator). The regnal year in a citation is that of the session in which the Act passed, not the year of its royal assent, so a session that straddles two years is cited with both, such as 13 & 14 Cha. 2. Use this converter to turn the citation into dates and to check which calendar year you are in; take the chapter number from the statute book.

Common Mistakes

• Treating the regnal year as the calendar year. 13 Cha. 2 is not 1613 or 1713: it runs from January 1661 to January 1662.
• Forgetting that the old year began on 25 March. A February 1661 document is dated 1660/61; a bare 1660 or 1661 can be wrong by a year.
• Mixing the calendars. A Julian date and a Gregorian one differ by ten or eleven days in the 1600s and 1700s, enough to fall in a different regnal year.
• Dating by the royal assent. An Act is cited by its session's regnal year or years.
• Assuming every reign starts at the coronation. Years are counted from the accession, and Charles II's from his father's execution.

Frequently Asked Questions

What does 13 Cha. 2 mean?

It is the 13th year of the reign of Charles II. His regnal years count from 30 January 1649, the day his father was executed, so the 13th year ran from 30 January 1661 to 29 January 1662 in the Julian calendar the English then used. The Corporation Act, passed in December 1661, is 13 Cha. 2 St. 2 c. 1; an Act of the spring of 1662 is cited to the 14th year.

How do you convert a regnal year to a calendar year?

Find the day the monarch acceded, add the regnal year number minus one to that year, and the result is the day the regnal year begins; it ends the day before the next anniversary. For example, George III acceded on 25 October 1760, so 41 Geo. 3 runs from 25 October 1800 to 24 October 1801. Some reigns, such as John's, Charles II's and George II's, need the special handling described above.

What is the current regnal year?

From 8 September 2026 it is the fifth year of Charles III, written 5 Chas. 3, and it runs until 7 September 2027. Elizabeth II's 71st and last year ran from 6 February 2022 to 8 September 2022, when Charles III's first year began.

Why do dates before 1752 have two years?

Because the English legal year began on 25 March until 1751. A date from 1 January to 24 March was written with both years — 30 January 1660/61 — to show the old year and the modern one. England moved the start of the year to 1 January in 1752 and dropped eleven days in September.

When did Acts stop being cited by regnal year?

In 1963. The Acts of Parliament Numbering and Citation Act 1962 switched citation from the regnal year of the session to the calendar year, so the Acts of 1963 on are numbered by year, as in Data Protection Act 2018, c. 12. Regnal years are still seen on older Acts and legal documents.

How do you cite an old Act by its regnal year?

Write the number and the monarch, then the chapter: Crown Debts Act 1801 (41 Geo 3 c 90) in OSCOLA, or 41 Geo. 3 c. 90 with full stops on legislation.gov.uk. Use the regnal year of the session in which the Act passed, and both years for a session that crosses two.

Do Scottish Acts use the same regnal years?

Not before 1707. This converter covers the regnal years of English and British monarchs, which Acts of the Parliaments of England, Great Britain and the United Kingdom use, and they carried on unchanged after the Unions of 1707 and 1801. Acts of the old Parliament of Scotland were dated by the Scottish count, which can differ: James VI of Scotland was already in his 36th Scottish year when he became James I of England in 1603.