You Need a Budget 3 is a lightweight, easy-to-use financial planning application built on a “living budget” system. The result is a fresh take on financial planning, albeit one that comes with a slight learning curve.

Central to You Need a Budget (YNAB) is the concept of a “living budget,” or one that changes as your financial needs evolve. The entire YNAB system revolves around four simple rules: give every dollar a job, save for a rainy day, roll with the punches, and stop living paycheck-to-paycheck. The idea is that these four rules will keep you on your financial feet and protect you from financial disaster.

As its name implies, YNAB takes budgeting seriously. In fact, every time you add funds to an account, you are asked to designate the funds as available income either now (“this month”) or later (“next month”). And that’s one of the key tenets of the YNAB system—you always plan for the future. The system forces the user to plan one month ahead all of the time, which developer YouNeedABudget.com calls the buffer. The goal: Create a financial buffer large enough to equal a single month’s income. This prevents financial collapse in the event of a large, unforeseen expenditure.

I tested YNAB using a sample budget provided by the developer. The sample budget included checking, savings, and credit cards accounts. I added, removed and edited transactions with ease. I categorized purchases and payments and set recurring payments to automatically transfer from one account to another. Users can also import data from Quicken or a bank statement—I found the process to be relatively easy in my tests. I also thought that navigating through YNAB’s bright, colorful screens was a breeze thanks to the application’s slick Adobe AIR interface. (Because the application can run on any system that supports Adobe AIR, Mac users can share YNAB 3 files with compatible Linux and Windows machines without having to convert the files.)

The true value of any financial program lies in its ability to track your financial health. To that end, YNAB offers a series of in depth reports on your spending habits, expenditures, and overall net worth. The system alerts you of overspending and reallocates funds from your buffer to cover any shortfall. YNAB is full of helpful, little touches like mouse-over instructions and clickable charts and graphs that make it easier to sort out your financial data.

After using YNAB to paint a picture of your financial health, you can then export your data in either CSV or Quicken’s QIF format. You can also carry your data with you via an iPhone companion app, which allows you to enter transactions and check your finances on-the-go while syncing your data between your Mac and your iPhone over Wi-Fi. (I also review You Need a Budget for the iPhone elsewhere on Macworld.com.)

While YNAB is a strong, well-rounded financial application, it does have a few small drawbacks. The application has a steeper learning curve than what you’d find with similar programs. To make the transition a little easier, YNAB’s developer includes a lengthy manual with the software that’s so thorough, it reads like chapters in a financial workbook. Free webinars on the YNAB Website also help anyone interested in learning more about the application’s approach to finance.

I also found YNAB’s interface to be slightly inconsistent. For example, while I could click on a category of a pie chart for a breakdown of how I spent funds, I was unable to do the same thing when the same data was in spreadsheet form. Still, that’s an admittedly minor complaint.

I was less impressed with YNAB’s companion iPhone app. While it’s certainly convenient, it can only be used to add new transactions; you can’t edit previously entered transactions or make changes to your overall budget. That’s not a lot of functionality for the mobile app’s $10 asking price. On the other hand, you certainly don’t need to download the mobile companion to get the most out of You Need a Budget.

Macworld’s buying advice

As a whole, You Need a Budget is a complete financial package. It teaches financial discipline through its unique system offering robust features and plenty of customization. You Need a Budget is a valuable financial tool.

[Macworld contributor Brendan Wilhide covers the sports industry and social media on Sportsin140.com.]