For many people, one of the most daunting and awkward conversations they can have with their manager is about money. Let’s say this is you. You’ve put in hard work and done your research, and you believe you deserve a raise. So how much do you ask for and when? Here’s your guide.

How much to ask for

There’s evidence that you’re more likely to get a bigger raise if you ask in terms of percentages instead of dollars. This is because the percentage will feel less tangible. Think about it: If you are making $50,000, what feels more substantial to you — getting a 10 percent raise or $5,000 more per year? Probably the $5,000, since you (and your boss) can immediately imagine what the extra $5,000 could buy. It has tangible value, whereas 10 percent is an abstraction or representation. What can you buy with 10 percent?

Just to keep you at your company, your boss might give you a five percent raise if you ask for one, but if you want 10 percent or more, you will need to make a compelling case using data. (You can also take more risks if you have another position lined up.)

I personally believe that 10 to 15 percent is the perfect amount to ask for unless you are being wildly underpaid based on your market and company value. If you do find that you are really underpaid (to the tune of 20 percent or more), then you can go in with your research and ask for a raise that pays you at least the market rate for your position. Ask for the upper bounds of the salary range.

If you are getting paid significantly under your market value, then you realistically could get a raise of 20-plus percent to the market level by making the case, again using the data, which you can collect online and from recruiters. If you get the raise, that’s an incredibly high return on investment for just doing a bit of research. If your company wants to keep you (and they have the money), they will give you a raise to get you at market rate. Not all companies will be in a position to give you a raise, and some will be but will say no. Even if you ask, there are many excuses bosses use to say they can’t give you a raise — like “we didn’t hit our numbers,” “sales are down,” or “we don’t have the budget.” It’s up to you to decide if you believe them and if you’re willing to stay under those circumstances.

When in the year to ask

If you’ve done all the research and are determined to ask for a raise, the next step is to think about the timing.

A lot of employees don’t know when to ask for a raise, or they ask at the wrong time. First, look at where you are in your career and your responsibilities. It’s important to regularly monitor your market value and the value you bring to your company. That means at least twice a year, and more if your job responsibilities change.

Your annual performance review is a natural time to ask because your boss is already thinking about your value to your company. If you come with your market-value research, you are significantly more likely to get a higher raise. Another natural time is at the end of the company’s fiscal year, when your boss is already thinking about next year. As long as your company is performing well, you are more likely to get a yes. (If your company isn’t performing well, then it’s unlikely you will get a raise, unless your company determines they really need to keep you to get the numbers up.)

Another good time is if your responsibilities have significantly changed or your workload has increased because of employee turnover or consolidation. Under these circumstances, the last thing your company wants is another employee to leave, so they might pay you more to keep you. Likewise, if you launched an initiative or project that is now a big success, that is another good time to ask. Ride on your accomplishments.

When in the week to ask

The next step is to pick the day and time. On a random Tuesday at 4 p.m. when your boss is stressed out is not a good time. On a Friday afternoon before a holiday or right before your boss is due to go on vacation is also not a good time. Monday mornings are also not good because who actually likes Monday mornings?

Research shows that the best time to ask for a raise is Friday morning. The reason is because your boss is, like you, relatively relaxed and excited about the weekend. Psychology research also shows that people tend to be more generous in the morning before noon.

No matter what day or time it is, you definitely want to feel out your boss’s mood. Your boss could be stressed, upset, or focused deeply on something else. If bosses are distracted or stressed, they aren’t going to listen to you the same way they would if they were more focused. Find a time when both you and your boss are in a good mood.

While these guidelines can be helpful, your best opportunity could come at any time. Be ready.

From Financial Freedom: A Proven Path to All the Money You Will Ever Need by Grant Sabatier, published by Avery, an imprint of The Penguin Publishing Group, a division of Penguin Random House, LLC. Copyright © 2019 by Millennial Money, LLC.