DaySums is a small collection of free date and time calculators built on one belief: a date question deserves a clear answer, immediately.
Every tool here:
- Runs entirely in your browser. The dates and times you enter are never sent to a server, stored, or shared.
- States its conventions. Whether a count includes the end date, which day counts as day one, and which weekend the tool assumes are always spelled out.
- Requires nothing from you. No account, no email, no app install.
DaySums is a sibling site of EvenSums, which does the same thing for money questions.
How the site is funded
DaySums is free to use and supported by advertising. Ads never change the results the tools produce.
Accuracy
All date math runs on UTC calendar days, which makes the tools immune to daylight saving quirks. Even so, these are general-purpose tools: for legally significant deadlines (court filings, contract dates, visa windows), always confirm with the relevant authority, since local rules about weekends, holidays, and inclusive counting vary.