At a point, you will notice you are doing more than you are paid for. However, the bosses always fail to notice, which is why you may have to speak up to get what is commensurate to your efforts. Yes, asking for a pay raise may be nerve racking, you are not sure of how much you should ask, or whether you may be sacked for asking for more.
The thing is if you are sure that you are deserving of a pay raise, never be afraid to bring it up. Don’t be one of the millions globally who complain about their salary but decide to do nothing about it. No need to be afraid, so far you are professional about asking, there’s nothing to lose.
However, a feeling of being underpaid isn’t enough; you need to be sure of what your peers in the same industry are earning. It’s not uncommon in firms to see new people getting paid higher than the oldies.
Now to how you can get a pay raise. Please don’t send a long mail detailing how many years you’ve spent and how you have helped the company, do it in person. Being a face to face request, it will be difficult to turn down your request. By meeting with your manager, you can measure their reaction and put up a counter-argument when they say No.