Perhaps you’ve heard the expression “there is no free lunch.” The idea is that you shouldn’t be able to receive something for nothing. Whether it is with money or with your time and labor, you must always “pay” for something one way or another.

That’s an interesting concept, but whoever invented it failed to look at the U.S. tax code, which is full of free lunches. Today I’d like to discuss one such example, which may be of interest if you are charitably inclined.

By way of background, one of the most talked-about changes in the new tax law is a provision that changes how deductions are treated. Specifically, in the past, you were able to deduct from your federal tax return the entire amount you paid in state and local taxes, including real estate taxes (often abbreviated as SALT). Under the new rules, however, taxpayers can deduct just $10,000 of SALT taxes. At the same time, the “standard deduction” was nearly doubled, to $24,000 for a couple filing jointly. Because of these changes, many taxpayers who previously were able to itemize their deductions — and thereby receive a benefit for each and every charitable donation — are no longer able to do so. Instead, they may be limited to the standard deduction.

Let’s see how you might be able to use these changes to your advantage. Suppose you and your spouse earn a combined $250,000, and suppose you like to give away 5% of your income, or $12,500, each year. To make these contributions, you could take the traditional approach and simply write out checks directly to your charities. But there’s a better way — a much better way — that will result in a fairly substantial free lunch.

Here’s how I would approach it: Instead of giving away $12,500 every year, give away twice as much, or $25,000, every other year. Over time, the total will be the same, but in some years you’ll double up your donations, and in some years you won’t donate anything. Of course, the charities that depend on your check every year may not want to switch to an every-other-year schedule, but I have a solution for that. It’s called a donor-advised fund (often abbreviated DAF). If you are not familiar with it, a DAF is a sort of hybrid between a charity and a checking account. The charity part issues you a receipt right away when you make a donation. But, the checking account part holds on to your funds, in a separate account earmarked for you. Your money doesn’t go anywhere until you ask the DAF to send a check to one of your charities, and you can do that at any time. In combination, these two aspects of a donor-advised fund allow you to schedule your donations for tax purposes every other year, while still allowing you to send your favorite charities a regular contribution check every year.

Let’s look at how this might work out on your tax return, comparing the traditional approach to the approach that I am describing:

Scenario 1 (the traditional approach): Make $12,500 of charitable donations every year
In this case, you start with your income of $250,000. Then, you subtract your deductions: The maximum for state and local taxes is $10,000, and your charitable donations are $12,500. That adds up to $22,500. Because this is less than the standard deduction of $24,000, you opt for the larger, standard deduction. That makes your taxable income $226,000 and your tax bill $42,818.

Scenario 2 (donor-advised fund approach): Make a $25,000 donation every other year
Again, you start with your income of $250,000 and subtract your deductions. Your state and local taxes are still capped at $10,000, but now your charitable contributions are $25,000, making your total deductions $35,000. This is far above the standard deduction, so you can now deduct the entire $35,000. This brings your taxable income down to $215,000 and your tax bill down to $40,178.

The result: In scenario 1 your tax bill was $42,818, but in scenario 2 it was quite a bit lower, at $40,178, providing a savings of $2,640. Of course, you will only realize this savings every other year, when you make your charitable contributions. But here’s an important point: In the years that you don’t make any donation, you still get to take the standard deduction, so your tax bill isn’t any higher than if you were to make a $12,500 contribution. That’s why it’s so important to double-up your donations in the years that you give so that you receive the full tax benefit.

Is this truly a free lunch? I believe so. Yes, it requires a little bit of administrative work, and the donor-advised funds do charge some minimal fees. And, of course, you’ll want to verify with your own tax advisor that this strategy will work with your overall tax picture. For many people, though, it’s hard to see why you would not want to do this.

One more thing: Donor-advised funds also make it easy for you to donate appreciated stock, which they will sell, allowing you to donate the cash proceeds to charities. In addition to convenience, this provides an additional tax benefit because it allows you to completely sidestep the capital gains taxes that would have been due if you had sold the stock yourself. If you have an established stock portfolio with unrealized gains, I would definitely explore this strategy too.