If you’re monitoring your credit score and trying to improve it over time (aren’t we all?), you may have wondered what moves would make the biggest difference. Are you better off paying down multiple balances or focusing on one debt at a time? Should you close an old, inactive account or just keep it open?

No matter how much Googling you do and how many great blogs you read (such as this one), the answers often come down to: It depends. The impact of each of these financial moves on your credit score is really dependent on your own unique credit history. Depending on what already exists on your credit report, how long your history is, and even the types of debt you hold, the answer can vary. That’s why a credit simulator can be the perfect tool.

I’m constantly checking my credit using free services like Credit Sesame and Credit Karma, in addition to obtaining annual credit reports. Both my Discover it and Chase Sapphire Preferred cards offer me free score checks, as does my bank (Capital One). Plus, I have alerts to let me know when there is a score change or something new is reported.

This makes it easy to watch the impact that my monthly payments, balance changes, and aged-off inquiries affect my score. But what if I want to know the impact of a paid-off account or credit limit increase beforehand? Or if I want to make the biggest jump possible, and need to know where to direct my efforts? In that case, I’ll need to use a simulator.

Credit score simulators do exactly what their name implies. They help you better understand how specific financial moves could impact your credit score, by quantitatively demonstrating their effect. They take your unique credit report into account when determining the impact of various credit-related moves, as opposed to just giving you general advice.

You can test multiple different approaches, such as paying off a credit card, clearing out all of your debt, opening a new account, etc. If you are considering a specific financial product in the near future, such as a home mortgage, this can help you know where to focus your efforts first.

Credit simulators have been around for many years, but they have really grown in popularity recently. Thanks to the prevalence of smartphone apps and credit monitoring services, simulators can be found almost anywhere. Plus, these tools are not only easy to find… they are also typically free.

For instance, many of the banks and credit cards that provide credit score updates also offer score simulators. You can find simulators through score monitoring sites like Credit Karma, too.

One of the newest simulators on the market, however, is really making waves… and the best part is that it’s from FICO. The new feature, called the FICO Score Planner, does more than just predict the impact that certain changes will have on your credit score. It will actually evaluate your current score, let you know what’s weighing you down the most, and offer tailored suggestions for reaching your goals.

No, a credit simulator won’t impact your score in and of itself. It can be an incredibly useful tool for finding out exactly where your weaknesses lie, though, and what you can go to make improvements. By using one of these free tools, you’ll know exactly how to boost your credit score in no time.