180 Day Calculator
Pick a start date and instantly find the date 180 days later, or work backward from a target date to find when the 180-day window began. Choose between calendar days (every day) or business days (Monday to Friday, with an option to skip US federal holidays). The result shows the full date, day of the week, and the span expressed in weeks and hours.
What is the 180-day calculator and when do you need it?
A 180-day calculator adds exactly 180 days to a chosen date and tells you the resulting calendar date, including the day of the week. The reverse mode works backward: you supply the deadline and the calculator tells you when the 180-day clock started. This matters in dozens of real-world situations. The Schengen Zone rules allow travelers to stay 90 days in any 180-day rolling window, so knowing both endpoints is essential for avoiding an overstay. US tourist visa holders are allowed up to 180 days per admission. Six-month deadlines appear in contract law, tax filings, insurance claim windows, employment probation periods, and regulatory notice requirements. Using a calculator avoids the common mistake of simply adding 6 calendar months, which can give a different result depending on which months are involved (February is 28 or 29 days; some six-month spans cover 181, 182 or 183 days).
Calendar days versus business days for a 180-day count
For most official deadlines, including visa rules, legal statutes and insurance policies, the 180-day window is measured in calendar days, counting every day including weekends and public holidays. Business-day counting is used in employment contracts, payroll, court scheduling and some commercial agreements, where weekends and holidays do not count. Choosing the wrong mode can shift your deadline by 50 or more days: 180 business days is roughly 36 calendar weeks, or about 252 calendar days. The "business days excluding US holidays" option subtracts the 11 main US federal holidays on top of weekends, pushing the end date even further out. Always check the governing document (visa rules, contract, regulation) to see which day type applies.
The Schengen 90/180 rule explained
The Schengen Area applies a rolling 180-day window rather than a fixed calendar period. The rule is: at any given day, look back 180 days and count how many days you spent in the Schengen zone. You may not exceed 90 of those 180 days. Because the window rolls forward every day, the math is more involved than a single 180-day calculation. To check compliance, count backward 180 days from your intended departure (or any day you want to check), then count the Schengen days inside that window. This calculator handles the single-window calculation. For a full rolling-window compliance check, you need to track each entry and exit date and repeat the calculation for every day of your trip.
How to use the backward (reverse) mode
The backward mode answers the question "my deadline is date X, so when did the 180-day window begin?" Enter your deadline date, select the day-type matching your context, and the calculator subtracts exactly 180 days to give the start date of the window. This is useful when you receive a notice with an expiry date and need to know the earliest date to which it applies. For example, an insurance policy may require a claim within 180 days of the loss. If you know the policy expires on a particular date, you can find the furthest-back date from which a loss would still be claimable.
Common uses for a 180-day window
| Context | What the 180-day window represents | Days counted as |
|---|---|---|
| US visa (tourist) | Maximum continuous stay per entry | Calendar days |
| Schengen zone travel | 90-day limit within any 180-day rolling window | Calendar days |
| Insurance claim deadline | Time to file after an incident | Calendar days |
| Employment probation | Standard review period at some employers | Calendar days |
| Tax election filing | IRS deadline for certain elections after tax year | Calendar days |
| Legal notice periods | Six-month statute of limitations for some contracts | Calendar days |
| Business project cycles | Half-year sprint or planning horizon | Business days (varies) |
Many legal, regulatory, and personal contexts use 180 days as a standard deadline.
Frequently asked questions
What is 180 days from today?
Set the calculator to "180 days forward from a date," leave the start date as today, and the result shows the exact date. For example, 180 days from June 12, 2026 is December 9, 2026. The day of the week and equivalent week count are shown alongside the date.
Is 180 days the same as 6 months?
Approximately, but not exactly. Six calendar months can span 181, 182 or 183 days depending on which months are included and whether a leap year is involved. The only month combination that gives exactly 180 days is a range that avoids long months at both ends. For legal or regulatory purposes, always use the day count specified in the rules rather than converting to months.
How many business days are in 180 calendar days?
In a typical 180-calendar-day stretch there are about 128-130 business days (weekdays only), depending on how many weekend days fall in the range. If you exclude US federal holidays as well, the number drops by roughly 6 to 8 more days. To go the other way, 180 business days is approximately 252 calendar days.
How does the Schengen 90/180 day rule work?
For any day you are in the Schengen Area, look back 180 days. The total number of days spent inside the Schengen Zone in that window must not exceed 90. The window is rolling: it shifts forward every day, so the start of the 180-day lookback also moves. You can use this calculator to find the start of any specific 180-day window, but full compliance checking requires logging every entry and exit date and repeating the calculation for each day of your trip.
Does the start date count as day 1 or day 0?
This calculator uses the standard convention: the start date itself is day 0, and the first full day away from it is day 1. So 180 days from June 1 is November 28, not November 29. This matches how most legal and visa rules count: the day of the event or entry is excluded from the count.
Can I calculate 180 days backward from a deadline?
Yes. Switch the mode to "180 days backward from a date," enter your deadline or expiry date, and the calculator subtracts 180 days to show the start of the window. This is useful for insurance claim cutoffs, legal notice periods, and visa expiry lookbacks.
What if my 180th day falls on a weekend or holiday?
For calendar-day counts the deadline is exactly that date, even if it is a Saturday or Sunday. Many legal and administrative deadlines move to the next business day if the final day falls on a weekend or holiday, but the rule depends on the specific jurisdiction or contract. The calculator shows the day of the week so you can spot this and adjust manually if needed.