Subtract Days from Date Calculator: Find Deadline Lookback Date, EEOC 180-Day Window, IRS 3-Year Amended Return, Statute of Limitations

Enter today’s date in the calculator and click the 30-day preset to find exactly what date falls 30 calendar days before today. For a quick estimate: subtract 1 month from today, then add or subtract 1-3 days to adjust for the variation in month lengths (30 or 31 days). For example, if today is August 23, then 30 days before is July 24. If today is March 15, then 30 days before is February 13 (since February has 28 or 29 days in a leap year). The calculator handles all these month-length variations automatically. The 30-day lookback is the most commonly used consumer protection window for returns, IRS notices, and credit card disputes.

Ninety calendar days is approximately 3 months, but not exactly, because months have different lengths. The 90-day preset in this calculator gives the precise calendar date. As a reference: 90 days before January 1 = October 3 in a regular year (not exactly October 1 = 92 days, or September 1 = 122 days). Common 90-day lookback uses: prescription refill eligibility windows (most pharmacy benefit managers use a 90-day supply covered at lower copay after a 90-day supply initial fill), IRS audit lookback window for some categories, B-2 visa waiver program stay limit, and employment probationary periods. The 90-day window for Visa Waiver Program entrants is exactly 90 calendar days from the date of entry, not 3 calendar months.

One hundred eighty days is approximately 6 months (with slight variation due to month lengths). The 180-day EEOC deadline applies in states and jurisdictions without a state or local Fair Employment Practices agency. An employee in a state with an FEP agency has 300 days to file. Because nearly every US state now has an FEP agency, most workers have the 300-day window. However, the employer or employee may not know which window applies, and missing either deadline bars the claim permanently. Use the 180-day preset to calculate the strict minimum window; use the 300-day preset to calculate the extended window available in most states.

Enter the date of the alleged harmful event as the “from” date and subtract the applicable statute of limitations period in days. Common periods: 730 days (2 years) for personal injury and medical malpractice in many states; 1,095 days (3 years) for federal IRS claims and contract disputes in some states; 1,460 days (4 years) for breach of written contract in many states; 2,190 days (6 years) for IRS fraud claims and contract claims in some states. The result shows the date after which the claim was no longer timely. If today’s date is before that result date, the statute may still be open. Always apply the discovery rule carefully, as it can shift the start date in latent harm cases.

Fourteen days is exactly 2 weeks, so the result is always the same day of the week as the starting date, just 2 weeks earlier. Example: 14 days before Wednesday, September 10 = Wednesday, August 27. The 14-day window appears in employment law (standard notice periods in some jurisdictions), lease termination notices for short-term tenancies, and consumer product return policies for some retailers. Medical and dental appointment cancellation policies often use 24 to 72 hours, but some specialist practices require 14-day advance notice for cancellations without a fee. The 14-day preset in this calculator always gives the exact 2-week prior date.

365 calendar days before a date is approximately 1 year before, but not exactly 1 year before if a leap year falls between the two dates. Example: 365 days before March 1, 2025 = March 2, 2024 (not March 1, 2024), because 2024 is a leap year and the 365-day count back from March 1, 2025 crosses February 29, 2024. If you need exactly 1 year prior (same date last year), use Add Days to Date with 366 days for a range crossing a leap day, or simply set the year back by 1. For legal purposes requiring “365 calendar days,” use the day count, not the annual equivalent. The FMLA rolling 12-month lookback uses 365 calendar days, not the calendar year.

This calculator flags weekend and holiday results and shows the nearest previous business day. However, the rule for whether a deadline shifts to the next or previous business day depends on the specific law or contract involved. Federal courts (FRCP Rule 6(a)) extend deadlines falling on weekends or holidays to the next business day (forward). Some state courts follow a similar rule. Tax deadlines also shift forward. But when you are calculating a lookback window (N days before a deadline), a result on a weekend simply means the relevant period starts on that calendar date regardless of day, and the action must be taken before the period expires. Always check the governing rule for your specific situation.

Sixty calendar days before a date is approximately 2 months prior (again, exact date varies by month lengths). COBRA continuation coverage gives qualified beneficiaries 60 calendar days from the later of coverage loss or COBRA election notice date to elect continuation coverage. To find the election deadline, add 60 days forward from the qualifying event date. To verify whether you are still within the window, subtract 60 days from today to see the earliest qualifying event date that is still timely. COBRA elections are strictly calendar day deadlines. Missing the 60-day window permanently waives COBRA rights for that qualifying event.

This calculator uses the “elapsed days” convention: it does not count the starting date. Subtracting 30 days from September 20 gives August 21 (30 days have elapsed, not counting September 20 itself). This is the legal default under Federal Rule of Civil Procedure 6(a): do not count the day that triggers the period. For legal deadlines, this is typically the correct approach. For inclusive counting (counting both the starting day and the end day), subtract 1 from your desired period and use that in the calculator. Example: to cover 30 days inclusive of the starting date, enter 29 days in the calculator.

Taxpayers can file an amended return (Form 1040-X) within 3 years from the original return’s due date or 2 years from the date tax was paid, whichever is later. “3 years from the due date” means 1,095 days (or 1,096 days if a leap year falls within the 3-year window). The due date is typically April 15 (or April 18 in years when April 15 falls on a weekend or holiday). If you filed on extension, the extension deadline, not the extension filing date, serves as the due date for 1040-X purposes. Subtract 1,095 days from the 1040-X deadline to confirm the oldest tax year still eligible for amendment. Per IRS Publication 556 at irs.gov.

One hundred twenty calendar days is exactly 4 months on average, but the specific date varies. Common 120-day lookback applications: Some state statutes of limitations for professional service claims run 120 days. Medicare’s timely filing deadline for claims runs 12 months from the date of service, but secondary payer coordination uses 120-day windows in some scenarios. Construction liens must typically be filed within specific periods (often 90-120 days depending on the state and type of work) from the last date work was furnished or materials delivered. Enter the applicable date and use the 120-day calculation to find the lien filing deadline or other lookback date.

This calculator accepts up to 36,500 days (approximately 100 years) backward from any starting date. This covers all practical legal, financial, and personal lookback windows, including 50-year property deed lookbacks used in real estate title searches and 30-year mortgage origination verifications. For genealogical purposes, JavaScript date arithmetic is reliable back to the early 1900s. For dates before 1900, the Gregorian calendar reform of 1582 and regional adoption dates create complications that this calculator does not address. For historical date work before the modern era, specialized calendrical software is recommended.

Two hundred seventy calendar days is approximately 9 months. The 270-day window appears in some IRS response timelines, extended insurance lookback periods, and construction contract warranty claim periods. It also represents the 9-month point of a 12-month FMLA lookback year. For project management, 270 days before a product launch date identifies the 9-month-out planning milestone. Enter the preset or type 270 directly to get the exact date 270 calendar days before your chosen starting point.

Yes. Real estate contracts use calendar day counting for inspection periods, earnest money deadlines, mortgage commitment contingencies, and closing date notice periods. A standard residential purchase agreement in the US specifies an inspection period (typically 7-14 calendar days from the effective date), a mortgage commitment deadline (typically 21-30 calendar days), and a closing date. Working backward from the closing date: if closing is October 15, the mortgage commitment was due October 15 minus 30 days = September 15. Title companies, real estate attorneys, and escrow officers routinely use backward date calculations to set calendar reminders and verify compliance with contract timelines.

Seven hundred thirty calendar days before a date is approximately 2 years, adjusted for any leap year. If the 2-year range includes February 29 of a leap year, the exact calendar count is 731 days, not 730. Entering 730 days for a range that includes a leap day will give a result that is 1 day later than the exact 2-year calendar anniversary. The 2-year statute of limitations is among the most common in US law: personal injury claims in many states, professional malpractice claims in some states (especially medical), breach of oral contract in many states, and certain employment discrimination claims. Always verify the specific statute for your state and claim type before relying on this calculation for legal purposes.

This calculator counts calendar days. For business days (Monday through Friday, excluding federal holidays), use the Business Days Calculator and enter a negative count, or count forward from a point that many business days in the past. As a rough guide: 30 business days is approximately 42 calendar days (6 calendar weeks). So 30 business days before a date is roughly 42 calendar days before it. This approximation works for most purposes. For exact business day counts, the Business Days Calculator handles this precisely, accounting for all 11 US federal holidays including the Martin Luther King Jr. Day, Presidents’ Day, and Juneteenth.