The middle-sized unit
Days are too many to picture and years too few to feel. Months sit in between. A life to ninety is 1,080 of them, enough to fill a page with detail, few enough to take in at a glance. They also carry the rhythm of the seasons, which is why the chart above colours each lived month by season and lets the bars rise and fall with the length of each month. Look along a row and you see ten turns of the year; look down the rows and you see the decades stack up.
Months are also how much of life is planned: rent and salaries, subscriptions, school terms, the gap between seeing old friends. Counting your months ahead makes those plans easier to picture.
How we calculate it
We count whole months from your birth date to today, where each month of life ends on your birthday date in the following month. The chart starts with the month you were born and wraps every 120 months, one row per decade of age. Full moons use the average lunar cycle of 29.53 days, and the months ahead are the whole months from today until the birthday you choose.
| Age | Months | Februaries | Full moons |
|---|---|---|---|
| 10 | 120 | 10 | about 124 |
| 30 | 360 | 30 | about 371 |
| 50 | 600 | 50 | about 618 |
| 80 | 960 | 80 | about 989 |
Worked example. Someone born on 12 April 1990 is 438 months old on 30 October 2026, with about 452 full moons behind them. Their 90th birthday on 12 April 2080 is 641 full months away, so three decade rows and most of a fourth are coloured in, with 36 Februaries among them.
A month at a time
One habit that suits this chart is a monthly review: on your month birthday, ask what the last month held and what the next should. It is frequent enough to change course and rare enough not to become a chore.
Questions people ask
Why are some bars taller than others?
Each bar’s height shows the number of days in that calendar month, so February is the shortest and the 31-day months are the tallest. Over a decade the pattern repeats like a heartbeat, with a slightly taller February every leap year.
What do the colours mean?
Months you have lived are coloured by season in the northern hemisphere: blue for winter, green for spring, yellow for summer and orange for autumn. Pale bars are the months still ahead. The outlined bar is this month.
Is the age I choose a prediction?
No. It only sets how many decade rows the chart shows, so you can see the months up to any age you like.
How are months counted?
A month of life ends on the same date as your birthday each month. If that date does not exist, such as the 31st in a 30-day month, the month ends on the last day of that month.
Sources. Gregorian calendar; mean synodic month of 29.53 days. Calculations run in your browser; nothing you enter is sent anywhere.