Explanation
The TEXT function can apply number formats of any kind, including currency, date, percentage, etc. By applying a number format like "00", "000", "0000", you can "pad" numbers with as many zeros as you like. Zeros will only be added where needed.
Number format only
The TEXT function converts numbers to text as a normal step in applying the number format.
If you are concatenating (joining) the result to another text string, this is fine, but if you just want to apply visual padding to a free-standing number set of numbers, you can apply a custom number format without using a formula.
Related formulas
Get week number from date
Related functions
TEXT Function
The Excel TEXT function returns a number formatted as text. This makes it easy to embed a formatted number (e.g., dates, times, currencies, percentages, fractions, etc.) in a text string with the number format of your choice.
WEEKNUM Function
The Excel WEEKNUM function takes a date and returns a week number (1-54) that corresponds to the week of year. The WEEKNUM function starts counting on the week that contains January 1. By default, weeks begin on Sunday, but this can be changed.
