About this calculator
Find calendar days and approximate weeks between two dates.
The calendar-day result excludes the start date unless you manually add one for inclusive counting.
Formula
Days = absolute difference between midnight dates ÷ 86,400,000 milliseconds.
Example
20 Aug to 25 Dec 2026 is 127 days.
Accuracy
NUMTX shows the assumptions next to the calculation so you can replace defaults with values that match your situation. For measurements, supplier rates, fees, interest, tax or regulated work, confirm important figures with the appropriate official or professional source.