How to ask for people’s age?

I've got a qns...
How to ask for people's age in japanese?
Shitsurei kamoshiremasen ga....
then?

Why would you need to? If you don't know the person well and have to ask so politely, then it might not be a good idea to ask at all. Unless you are doing a survey of some kind, in most cultures that's considered a personal question and not something you ask unless you know the person well. It's the same in Japan.

It is indeed rude to ask people age in most cultures.
Young people are afraid to be thought of as too young and immature and older people are afraid to be thought of as too old. Exceptions are older people in unusual good shape, like my grandma was before her untimely demise at 101. I overheard once telling someone that she was feeling a bit dizzy every time she was quickly climbing down from the dining room table after dusting the top of the china cabinet.The other person said: how old are you anyway? ma grandma chuckled I am only 99!

In other cultures yes, but,
I see it common that in Japan that people introduce themselves and say their age.

Not to mention in newspapers, magazines, television shows, and news often show the persons age in parenthesis right next to their name. Just tune on the television or pick up a newspaper right now and take a look.

And whos to say this guy is asking strangers this question, maybe he has indeed know someone but just wondering how old they are if they didn't introduce their age.

I agree that the original poster might just need it for some special reasons, so I'm going to give the sentences anyway :)
- O-ikutsu desu ka? (May I ask your age?)

(If in a bar or somewhere you need to check people's age to make sure they are not under age)
- Nenrei wo kakunin sasete itadaite yoroshii desu ka? (Could I please check your age? = polite but firm in a way... so this one is only good for asking to _check_ someone's age)

Thanks alot! I was doing a script for my Japanese language role play. So I needed that. Thanks alot!

It really depends on who you are talking to I suppose, yes it can be considered rude. My experience however (going to bars, clubs, and shopping) I have noticed that when talking to a gaijin, they don't really get offended and often reply to you in English because they want to practice it usually though they might be shy about it. In a converasation you could just simply say "Nansai desu ka?" That has seemed to work for me, no need on extreme formalities in certain settings.

well, if it is in case of a stranger indirect way is good. you may ask how long s/he has been working after graduating from school/university...and so on. this may not give you an exact age but you can guess.

one idea is to ask for the birth sign (snake, monkey,boar etc.) of course you have to know your own sign, to start the conversation..and you have carry the list of the years for each sign (don't look at it in their presence DUH!) For those not used to the system (from China), each year is symbolized by an animal and there are 12 animals, so different persons born under the same animal sign are born 12, 24, 36 etc. years apart. you can easily deduct the age of a person by looking at the dates chart and at their physical appearance.