Date Difference & Due Date Calculator
Accountants constantly count days: credit periods, interest days, notice periods, MSME 45-day payment limits, warranty and contract terms, TDS and GST due dates, employee tenure for gratuity. This calculator gives the gap between two dates in every useful unit, and can add or subtract days (calendar or business) to a date to find a due date.
Mode 1 — Difference between two dates
- Total days (optionally inclusive of both ends), weeks + days, calendar months + days, and years/months/days.
- Business days — Saturdays and Sundays excluded — with the count of weekend days.
- Decimal years (÷ 365.25) for gratuity, bonus and tenure calculations.
- A quick table of due dates at 30, 45, 60, 90, 180 and 365 days from the start date.
Mode 2 — Add / subtract days
Enter a start date and the number of days (negative to go backwards). Tick "business days" to skip weekends — e.g. a 10-working-day deadline. The result shows the date, weekday, financial year and quarter.
Worked example
Invoice dated 01-04-2025 with 45 days credit: 01-04-2025 + 45 days = 16-05-2025 (Friday). Days between 01-04-2025 and 16-05-2025 = 45 days = 6 weeks 3 days = 1 month 15 days; business days = 33.
Inclusive or exclusive?
Most interest and credit-period calculations exclude the start day (or the end day) — the gap from 1 April to 2 April is 1 day. Some statutes count both days ("within 30 days of receipt including the day of receipt"); use the inclusive checkbox for those.
Notes
Public holidays are not excluded from business days; the month+days figure uses calendar months, so 31 January to 28 February counts as exactly one month.
Where accountants use it
- MSME Act Section 15 — payment within 45 days of acceptance; Section 43B(h) disallowance check.
- GST — 180-day rule for ITC reversal on unpaid supplier invoices; 30-day limit for credit notes and e-invoice reporting.
- Income-tax — 5 years of continuous service for gratuity, 240 days for leave encashment, notice-period recovery.
Frequently Asked Questions
How are months calculated when months have different lengths?
Calendar months are used: the month count increases when the same day-of-month is reached; the leftover is shown as days.
Does business-day mode consider Indian public holidays?
No, only Saturdays and Sundays are skipped. Adjust manually for holidays such as Diwali or Republic Day.
How do I find a date 90 days ago?
Choose "Add / subtract days", enter −90, and the tool shows the date and its weekday.
Disclaimer: This tool is for general information and estimation only. Tax rates and rules change — verify with official sources or a professional before acting. Read full disclaimer.