I would imagine that most workers in the US don’t experience large income jumps after they start working full-time. They will receive periodic raises and perhaps some small jumps if they change career tracks or negotiate well with a new employer, but nothing like increasing their incomes by 50 or 100% at one time. However, those types of jumps are common for PhDs. The income jump from graduate school to a postdoc is roughly 50%, and the jump from a postdoc to a career job is perhaps another 50 to 100% or even more. At least, that’s the expected track! Having that expectation, whether or not it conforms with reality, can bring about some strange attitudes towards money. However, if a PhD(-in-training) adopts percentage-based budgeting, it has the potential to keep her finances in balance even through the income jumps.

What Is Percentage-Based Budgeting?

There are many versions of percentage-based budgeting in terms of how it is enacted and the appropriate percentages to assign to various budgeting categories. The foundation of all of them is that your financial goals and expenses should scale with your income according to a consistent percentage.

Retirement Savings Rate

The most common example of percentage-based budgeting is the advice to save a percentage of gross or net income for retirement. It’s not reasonable to say that everyone should max out their 401(k)s ($18,500 in 2018) every year – though I have read that advice time and again in the personal finance blogosphere – not only because not everyone has a job that offers a 401(k) but also because that would be an incredibly high savings rate for someone earning what a graduate student or postdoc does. It’s much more reasonable to assign a percentage for your retirement savings goal, e.g., 5, 10, 15, or 20%.

The big advantage for using percentages instead of absolute numbers for savings rates is that it allows you to create a positive financial habit or even becomes part of your character (“I am a saver; I contribute 10% of my gross income to my retirement account”) at a level that is possible for your income. As your income grows, your absolute contribution to your savings grows as well.

Other Budget Applications of Percentage-Based Budgeting

Tax

I like to think of income taxes as another type of percentage-based budgeting category, even though individuals don’t have control over the tax rate. If you have income tax withholding set up, you are sending a (more or less) fixed percentage of your gross income to the IRS throughout the year. If your withholding is accurate, this percentage is your effective tax rate. Your marginal tax rate is the tax rate on the income bracket that your income tops out in (e.g., 12%), but your effective tax rate is the amount of tax you actually pay divided by your gross income (e.g. 6%).

Another type of tax, FICA (Social Security and Medicare), is also percentage-based, although students and non-wage earners are exempted and the tax phases out at higher incomes ($127,200 in 2017).

Spending Categories

One of the most well-known percentage-based budgets is the Balanced Money Formula, which is detailed in All Your Worth: The Ultimate Lifetime Money Plan* by Elizabeth Warren and Amelia Warren Tyagi. It is a recommendation of how much of your net income to spend in three areas: 50% on needs, 30% on wants, and 20% on savings and debt repayment. The 50% of net income to needs (defined as housing and transportation; contracted payments; and basic food, clothing, etc.) is emphasized as the category that tends to grow out of control and lead to financial stress in American households.

[* This is an affiliate link. Thank you for supporting PF for PhDs!]

Further reading: A Graduate Student’s Balanced Money Formula

Dave Ramsey, a well-known get-out-of-debt financial guru, also makes budget category recommendations for his followers (after they have gotten out of non-mortgage debt). He lists percentage ranges for eight budget categories in addition to saving and giving, e.g., housing should be 25-35% of net income, food should be 10-15%, etc.

Further reading: Starter Percentages for an Every Dollar Budget

These percentage-based budget category suggestions are just that – recommendations based on what that particular expert has observed to work well for most American households. You will, of course, find your own levels of spending that feel comfortable for you. But these kinds of recommendations are great to compare with your current spending from time to time so that you can see if any category seems wildly out of line, especially if it’s a category you can adjust.

The advantage to basing your spending on percentages of your income is that, again, you spend less when you earn less and spend more when you earn more. Your lifestyle scales with your income, and you automatically live within your means.

Using Percentage-Based Budgeting on Only Part of Your Income

Percentage-based budgeting is a useful structure not only on your salary but also on any variable income you might have, such as from a side hustle. If you budget all your basic and regular monthly expenses on your salary, you can use your extra income to fund, in a percentage-based allocation, some extra splurges or savings.

For example, for every dollar of side income money you earn, you could allocate a percentage for taxes (I use my marginal tax rate plus 15.3%, the self-employment tax rate), a percentage for saving, and the remainder for little luxuries or lifestyle upgrades. That way, you both further your financial goals and reward yourself for a job well done.

Further reading: Side Income (Category), Best Financial Practices for Your PhD Side Hustle

What Are the Pitfalls of Not Using Percentage-Based Budgeting?

For PhD trainees in particular who are anticipating income jumps, it is very tempting to tell yourself that you will work on financial goals such as saving and debt repayment once you are earning more. In fact, you might even allow yourself to live above your means and accumulate some debt in the confidence that you will pay it all off later on.

Further reading: A Low Income Is a Blessing in Disguise

If you’ve ever heard of the permanent income hypothesis, you might be tempted to add its label to the above line of thinking. However, I think rather than a strictly rational calculation, it is simply our natural procrastination and fear of financial sacrifice disguising itself as a reasonable argument. Keeping a lid on your lifestyle is difficult when your income is low. Saving and debt repayment are difficult. We imagine a brighter future when those actions won’t be so challenging, and assume we can make it Future Us’s problem.

Further reading: You Should Spend More and Save Less (Especially Grad Students)

While I certainly hope that you experience the income jumps you anticipate – and don’t forget, there’s no guarantee that they will materialize – it doesn’t really become easier to save with age the way most people think it will. As the decades pass, on average your lifestyle starts to cost more and more. You buy a house. You have some kids. You upgrade your car. You’re pressed for time, so you don’t practice frugality the way you used to. The fact is there is always a reason not to make financial sacrifice today, especially if you’re an optimist. Percentage-based budgeting keeps your lifestyle in line with your current reality and doesn’t allow you to defer accepting responsibility for your financial life.

Where Does Percentage-Based Budgeting Break Down?

Low Incomes

Percentage-based budgeting works well over a range of incomes, but there is a floor to its functionality, and it’s somewhere around the living wage for each local area. At some point, when your income is low enough, you can’t scale your basic needs down to that ideal percentage of your gross income. And unfortunately, a lot of graduate students and some PhDs are living right around that breaking point. Savings/debt repayment will be cut back or eliminated, needs will balloon out of proportion, and there will probably be little spent on wants. You may even find yourself accumulating debt. The best solution to this conundrum is to land a higher-paying position as soon as you can, following graduation if necessary. A side income may help keep you afloat in the meantime, but don’t let it slow down your progress to that better job.

Taxes

Some percentage-based budgeting formulations, like the Balanced Money Formula and Dave Ramsey’s, work off your net (after tax) income. I like to work off my gross income and think of taxes as part of my percentage-based budget, but as I said earlier, your effective tax rate is not a percentage that you as the taxpayer control. As your income increases, all else being equal, your effective tax rate will increase as well, meaning that everything else has to shift to accommodate it, so your percentages cannot stay totally fixed.

My Experience with Percentage-Based Budgeting

I implemented percentage-based budgeting early on in graduate school for my high-level financial goals that are still the same today. I paid my taxes (through quarterly estimated tax, at times!), contributed to my Roth IRA (starting at 10% of gross income, working my way up to 17% by the end of grad school, and 18% today), and tithed. Beyond that, I did check that my spending on needs and wants was more or less in line with the Balanced Money Formula. I found that a 5:3 ratio of spending on needs to wants is quite comfortable.

I’m so glad that I implemented percentage-based budgeting, at least for my high-level goals, during grad school. It has helped my husband and I keep perspective about our finances through the income increases and moves we’ve undergone. We now have one regular income (my husband’s salary) and a few variable income streams (from my business and side hustle), and we practice slightly different forms of percentage-based budgeting with each. We pay taxes (at different rates), contribute to our retirement accounts, and tithe from each income, but we budget all our expenses off my husband’s income and use mine for extra saving (usually for a house down payment).

Probably the thing I like best about percentage-based budgeting is that it’s so flexible; you can make it entirely your own based on your goals and your lifestyle preferences. Yes, there are guidelines out there for you to access if you want to, but the final decision is yours. If you find a comfortable ratio among savings, needs, and wants while your income is low and maintain it as your income grows, you can confidently enjoy the fruits of your success.