How are weeks and days counted?

The tool counts the exact whole days between the two dates, then divides by seven. The result shows complete weeks plus the remaining days, and also the total weeks and total days for convenience.

Why use weeks instead of months?

Weeks are commonly used for infant age (such as a baby's age in weeks) and for pregnancy and milestone tracking, where months can be ambiguous because they vary in length.

Is my date of birth uploaded?

No. Everything is computed locally in your browser — your dates never leave your device and nothing is stored.

Age in Weeks and Days Calculator

Convert any age or date span into weeks and days.

Calculate an age in weeks and days

Express any age or date span as whole weeks plus leftover days — the format used for infant age, pregnancy milestones, and project tracking where months are too coarse. Enter a date of birth (or any start date) and an end date, and the calculator returns the exact weeks-and-days breakdown along with total weeks and total days.

All the arithmetic happens in your browser, so your dates never leave your device.