183 days in months
183 days is about 6 months (6.01 months, or 26 weeks and 1 day). It is the smallest whole number of days that is more than half of a 365-day year, which is why it is the most common tax-residency threshold in the world. Convert any threshold below.
6.01
About 6 months, using the average calendar month of 30.44 days.
26.14
26 weeks and 1 day
50.1%
of a 365-day year
6 consecutive calendar months can be as short as 181 days or as long as 184 days, depending on which months they are. That gap is why a statute written in months and a threshold written in days are not interchangeable.
Why the answer is “about” six months
A calendar month is not a fixed length. Six consecutive months run from 181 days (February through July in a non-leap year) to 184 days (March through August), depending on which six you pick and whether a leap day falls inside them. So 183 days lands near six months without ever being equal to it.
That imprecision is the reason tax law prefers days. A threshold of “183 days” produces the same answer for everyone. A threshold of “six months” does not, which is why the handful of US states that still write their statutes in months, Alabama and Oklahoma at seven months, Arkansas at six, leave a genuine ambiguity that is safest read the short way.
Common thresholds, converted
| Days | Months | Weeks | Where it applies |
|---|---|---|---|
| 90 | 2.96 | 12.9 | Schengen area (rolling 180-day window) |
| 180 | 5.91 | 25.7 | Thailand |
| 182 | 5.98 | 26.0 | India, Malaysia |
| 183 | 6.01 | 26.1 | The most common threshold worldwide |
| 184 | 6.05 | 26.3 | New York, New Jersey, Massachusetts, Connecticut |
| 200 | 6.57 | 28.6 | Oregon, Hawaii |
| 214 | 7.03 | 30.6 | Alabama, Oklahoma (statutes say seven months) |
| 270 | 8.87 | 38.6 | Idaho |
| 330 | 10.84 | 47.1 | US foreign earned income exclusion (FEIE) |
To count real days against a real threshold rather than convert units, use the 183-day rule calculator, or read the 183-day rule explained. If your threshold is the US one, note that the Substantial Presence Test weights three years together and is not a simple 183-day count at all.
183 days in months FAQ
How many months is 183 days?
183 days is approximately 6.01 months, using the average calendar month of 30.44 days. In round terms it is 6 months, which is exactly the point: 183 is the smallest whole number of days that is more than half of a 365-day year, which is why so many countries use it as their tax-residency threshold.
How many weeks is 183 days?
183 days is 26.14 weeks, or 26 weeks and 1 day.
Is 183 days exactly 6 months?
Not exactly, and the difference matters. Six consecutive calendar months run anywhere from 181 to 184 days depending on which six they are: February through July in a non-leap year is 181 days, while March through August is 184. So 183 days is close to six months but never identical to it, and a rule written in months will not resolve to the same date as a rule written in days.
Why do tax rules use 183 days instead of 6 months?
Because 183 is unambiguous. A year has 365 days, so 183 is the smallest whole-day majority: spend 183 days somewhere and you have spent more time there than anywhere else. 'Six months' would be ambiguous, since six months is a different number of days depending on where in the year it falls, which is exactly the dispute a tax authority does not want to have.
Which countries use months rather than days?
Several US states write their statutes in months and leave the day figure to be derived: Alabama and Oklahoma use seven months (roughly 214 days), and Arkansas uses six months (roughly 183 days). Because the statute is written in months, the day figure is an approximation, and the safe reading is the shorter one.
Does 183 days mean 183 days in a calendar year?
Usually, but not always. Most countries count within the calendar year, but the UK tax year runs 6 April to 5 April, Australia's runs 1 July to 30 June, and India's runs 1 April to 31 March. Schengen does not use an annual period at all, it uses a rolling 180-day window. Always check the counting period, not just the threshold.
Counting days, not months?
Tax Days tracks your real day count against the actual threshold in 200++ jurisdictions and all 50 US states, and warns you before you cross one.
