About this halfway date calculator
The halfway date is the day that splits a period into two equal halves: the middle of a pregnancy, a project, a school year, or the time between two anniversaries. The calculator counts the days between your dates and adds half of them to the start date. When the total is odd, the midpoint falls at noon, so you can round to the nearest day, the earlier day, or the later day, or switch to exact precision to see the hour and minute (in UTC). It also lists the 25% and 75% marks and other common checkpoints such as one third and two thirds, and shows how far through the span today is.
How to find the halfway date
- Enter both dates. Pick the start and end dates, or press an example such as a 40-week pregnancy or this year.
- Choose the precision. Keep whole days and choose how to round, or switch to exact to see the midpoint to the minute.
- Press Find halfway date. Read the midpoint, check the quarter points and other checkpoints, and see where today falls.
Frequently asked questions
How is the halfway date calculated?
Count the days from the start date to the end date and add half of that to the start. From 1 January to 31 December 2026 is 364 days, so the midpoint is 182 days after 1 January: 2 July.
What happens when the number of days is odd?
The exact midpoint falls at midday. Choose round to nearest, round down for the earlier day, or round up for the later day, or use exact precision to see 12:00.
When is the halfway point of a pregnancy?
A pregnancy is usually counted as 40 weeks, or 280 days, from the first day of the last period, so the halfway point is 20 weeks, or 140 days, after that date.
Are the start and end dates included?
The span counts the days between them, so the start date is day 0 and the end date is the last day. This matches how most date calculators measure periods.
What do the other checkpoints mean?
They are the dates at that share of the span, such as 25%, one third (33%), or 90%. They help plan milestones in projects, training plans, or long trips.