Which months are in each quarter?

Q1 is January–March, Q2 is April–June, Q3 is July–September, and Q4 is October–December. Each quarter is exactly three calendar months.

How is the quarter worked out?

The calculator takes the month number (0–11 internally), divides by 3 and rounds down, then adds 1. So January–March give Q1, April–June give Q2, and so on up to October–December for Q4.

How many days are in each quarter?

Q1 has 90 days (91 in a leap year), Q2 has 91 days, and Q3 and Q4 each have 92 days. The tool counts the exact days for the year you enter, so leap years are handled automatically.

What does "day of quarter" mean?

It is how many days into the quarter your date is, counting the first day of the quarter as day 1. For example, 1 April is day 1 of Q2 and 30 April is day 30.

Does this use a fiscal quarter?

No — this uses standard calendar quarters that always start in January, April, July and October. For non-calendar fiscal periods, use the fiscal year calculator.

Why might the start and end dates look shifted by a day?

They should not — dates are handled in UTC to avoid time-zone drift, so a quarter always starts on the 1st and ends on the last day of its third month.

Is anything uploaded?

No — every calculation happens locally in your browser and the date you pick is never sent anywhere.

Quarter Calculator — Gera Tools

Calendar quarter calculator

This tool tells you which calendar quarter any date belongs to and gives you the full breakdown of that quarter. Pick a date and you instantly see the quarter label (Q1–Q4 with the year), the quarter’s start and end dates, its total length in days, which day of the quarter your date is, and how many days are left until the quarter ends. It is handy for reporting deadlines, billing periods, OKR tracking, and “how long until quarter-end” planning.

How it works

Calendar quarters group the year into four three-month blocks. The calculator reads the month from your date (0 = January through 11 = December), then computes the quarter as floor(month ÷ 3) + 1. The quarter’s start is day 1 of the first month in that block, and its end is the last day of the third month. Total days are the inclusive count between start and end, the day-of-quarter is your date minus the start (plus one), and days remaining is total days minus day-of-quarter. All dates are computed in UTC so results never shift across time zones.

Example

For 2026-05-29 (29 May 2026):

Month is May → floor(4 ÷ 3) + 1 = Q2 2026
Quarter start: 2026-04-01, quarter end: 2026-06-30
Days in quarter: 91
Day of quarter: 59 (29 May is the 59th day of Q2)
Days remaining: 91 − 59 = 32

Quarter	Months	Typical length
Q1	Jan–Mar	90 days (91 in leap years)
Q2	Apr–Jun	91 days
Q3	Jul–Sep	92 days
Q4	Oct–Dec	92 days

Every calculation happens locally in your browser — no dates are uploaded.