Guides
Plain-English explanations of the topics behind our tools, with worked examples.
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How to Calculate Your Exact Age in Years, Months and Days
A step-by-step method for working out exact age by hand, why months make it tricky, and how leap years and February 29 birthdays are handled.
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Counting Days Between Dates: Calendar Days vs Business Days
How to count the days between two dates correctly, whether to include the first and last day, and how business days differ from calendar days.