Months From Today Calculator

Spin the Month Dial

Common Offsets

One-tap month jumps for billing cycles, fiscal quarters, and contract milestones.

Months → Target Date Table

Live from today: Saturday, May 30, 2026. All targets honour end-of-month clamping.

Need the reverse direction? Try 6 months ago or 1 year ago.

The Clamped Add-Months Formula

Days In Each Month — Reference

No saved calculations yet. Tap "Save to History" to remember up to eight entries — they live in your browser only.

How to Use the Month Dial

1. Set N with the + and − buttons or type a value (range −600 to +600). The dial rotates so the target month sits at the 12 o'clock position.
2. Read the target date in the inner ring of the dial — year on top, day in the middle, month beneath.
3. Watch for the amber CLAMPED flag. It flies whenever the day-of-month in the source did not exist in the target month (Jan 31 → Feb, Mar 31 → Apr, etc.). The flag tells you the day was reduced to the last valid day.
4. Cross-check the four micro-cards: total days between, weeks between, weekday, and day-of-year.
5. Tap Save to History to keep the calculation in your browser. Repeat for other offsets or use the Common Offsets chips.

A Brief History of Calendar-Month Arithmetic

In 2026, a commercial paralegal drafting a 36-month commercial lease in São Paulo or a billing engineer patching a Stripe subscription overflow in Berlin needs a calendar-month arithmetic that handles end-of-month clamping the same way every legal system in the world does. Months From Today plots an N-month forward or backward jump on a 12-position dial, surfaces the exact target date, the weekday, and the ISO week, and raises a flag whenever the source day-of-month does not exist in the target month.

The Gregorian calendar that governs civil dates was promulgated by Pope Gregory XIII on 24 February 1582 in the papal bull Inter gravissimas, replacing the Julian calendar that had drifted about 10 days from the astronomical equinoxes. The reform was designed by the astronomer Christopher Clavius and the physician Aloysius Lilius and adjusted the leap year rule so that centuries not divisible by 400 are common years — fixing the slow drift of the Julian system. Britain and its colonies adopted it in September 1752, Russia not until 1918, and Greece in 1923.

Calendar-month arithmetic in software is older than computers themselves. The first IBM mainframe billing systems of the 1960s already had to handle the Jan 31 → Feb 28 problem, and Grace Hopper's COBOL standard library (COBOL-68) defined ADD-MONTHS to clamp to the last valid day. The Oracle Database SQL function ADD_MONTHS, PostgreSQL's date_trunc + interval logic, and Java's Calendar.add(Calendar.MONTH, n) all preserve day-of-month and clamp on overflow. JavaScript's Date.setMonth, controversially, overflows instead — Mar 31 + 1 month becomes May 1 — which is why this tool exists as a calendar-correct alternative.

The ISO 8601 standard published in 1988 by the International Organization for Standardization codified the YYYY-MM-DD format and the ISO week-numbering convention used worldwide for project scheduling. The week starts on Monday, week 1 contains January 4, and a year has either 52 or 53 ISO weeks. The Scandinavian, German, and Swiss workforce default to ISO weeks; the US Bureau of Labor Statistics uses Sunday-start weeks. This calculator reports both.

Legal time-counting follows the Latin maxim dies a quo and dies ad quem — the day from which and the day to which. In Anglo-American jurisprudence, statutes of limitations typically use month-counting that honours end-of-month clamping. The US Federal Rules of Civil Procedure Rule 6(a) was rewritten in 2009 to clarify that 'a month' includes the corresponding numbered day of the next month, falling back to the last day if that number does not exist. The same rule applies in the UK Civil Procedure Rules and most EU national codes.

In financial mathematics, the day-count conventions of 30/360, ACT/360, ACT/365, and ACT/ACT govern how interest accrues over months. The 30/360 convention treats every month as 30 days and every year as 360, which makes Jan 31 to Feb 28 a 28-day month for interest but a full month for billing — an apparent contradiction that drove the development of the ISDA day-count standard. This tool computes calendar months for scheduling, not interest accrual; for that, use a dedicated bond pricer.

Modern HR and SaaS platforms — Workday, BambooHR, Stripe, Recurly, Chargebee — all standardise on the calendar-month clamping rule that this tool implements. The pattern is universal enough that the Unicode CLDR (Common Locale Data Repository) explicitly documents it in TR 35 §6.3 as part of the calendar arithmetic spec. The dial widget makes the rule visible: when a clamp happens the source day-number is shown alongside the clamped result, so legal and engineering teams can verify the date is the one their system will use.