The bill makes a new deduction available — and not just for 2020 — for up to $300 in annual charitable contributions. It’s available only to people who don’t itemize their deductions, and you calculate this new one by subtracting the amount you give from your gross income.

To qualify, you have to give cash to a qualified charity and not to a donor-advised fund, which is a charitable account that affluent people often use to bunch contributions in a particular year in order to maximize deductions. If you’ve already given money since Jan. 1, that contribution counts toward the $300 cap.

As part of the bill, donors can deduct 100 percent of their gift against their 2020 adjusted gross income. If you have $1 million of income, you can give $1 million to a public charity and deduct the full amount in 2020.

The new deduction is only for cash gifts that go to a public charity. If you give cash to, say, your private foundation, the old deduction rules apply. And while the organizations that manage donor-advised funds are public charities, you do not get the higher deduction for donating cash to your donor-advised fund.

If your assets are substantial enough that you can give more than your income this year, you won’t lose the deduction for the excess amount. You can use it next year, as has always been the case.