Making donations online has never been easier. But beyond finding out whether the charity you're giving to is reputable, understand why you may be asked to pay any fees or optional tips. Maria Korneeva/Moment RF/Getty Images

Americans have strong views on paying extra fees and tipping for services, especially at the holidays.

But what about when making online donations?

The holiday season is usually a big one for charitable contributions. Take Giving Tuesday – which falls on the first Tuesday after Thanksgiving in the United States. Last year it raised an estimated $3.6 billion in the United States. Roughly one-third of that came from online donations –- made either on a third-party online fundraising platform or through nonprofit organizations’ websites, which themselves may be power

See Full Page