DocomintCalculadora de Sumar/Restar Días
Calcula la fecha N días antes o después de una fecha dada.
What is a Calculadora de Sumar/Restar Días?
Answers "what date is 90 days from now" or "what date was 6 weeks before this one" directly, without manually counting across month boundaries of different lengths — enter a negative number of days to subtract instead of add.
How to use the Calculadora de Sumar/Restar Días
- Enter a start date and a number of days (negative to subtract)
- Press Calculate
- The resulting date and its weekday appear instantly, computed on your device
Formula
Result Date = Start Date + N days (N negative to subtract)
Adds N calendar days to the start date, correctly rolling over month and year boundaries of different lengths.
Example
90 days after August 8, 2026 lands on Sunday, November 6, 2026 — crossing three different month lengths (August's 31, September's 30, October's 31 days) that make hand-counting error-prone.
Common mistakes
- Entering a positive number when trying to go backward — use a negative number (e.g. -30) to subtract days instead.
- Confusing "days" with "business days" — this counts every calendar day, weekends included; see Business Days Calculator for weekday-only counting.
- Expecting a "3 months" or "1 year" input option — this only adds a day count, not calendar month/year units, which don't have a fixed number of days.
Frequently asked questions
Can I subtract days instead of adding them?
Yes — enter a negative number in the days field (e.g. -30) to go backward from the start date instead of forward.
Does this account for daylight saving time?
Date addition here works in whole calendar days, not elapsed hours, so DST transitions don't affect the resulting date — the date 30 days later is still exactly 30 calendar days later regardless of any clock change in between.
Can I add months or years instead of days?
Not directly — this tool works in a day count only, since months and years don't have a fixed number of days. Convert your desired span to an approximate day count first (e.g. ~30 for a month, ~365 for a year) if you need month/year-scale math.
Does this skip weekends automatically?
No — it counts every calendar day, including weekends. For a result that only counts weekdays, use Business Days Calculator instead.
Is my numbers uploaded anywhere?
No — Calculadora de Sumar/Restar Días runs entirely in your browser using JavaScript/WebAssembly. Your numbers is never sent to a server.