If you're already donating 10% of your income, taking a giving pledge might feel unnecessary. After all, you're already doing the thing. But in practice, pledging itself results in an increase in both the amount and efficiency of donations, even for people who are already committed givers.
It usually means you donate more. A pledge turns good intentions into a durable commitment. Psychologists call this a pre-commitment: by making a clear promise, you make it harder for your future self to quietly drift away from your values when life gets busy, finances feel tighter, or priorities shift. Giving stops being something you "try to keep up" and becomes a core part of your identity. Research on pledges suggests this kind of commitment increases both the likelihood that people keep giving and the total amount they give over time.
It helps you donate more effectively. Taking a pledge doesn't just reinforce how much you give—it sharpens how you give. When you've pre-committed a certain amount, you tend to view that more strategically and critically. Like your investments, you want to get the most "bang for your buck." Pledgers are more likely to reflect regularly on where their donations do the most good, learn from others, and update their choices as new evidence emerges. Being part of a community focused on effectiveness makes it easier to reason well about impact rather than defaulting to habit, convenience, or emotional pull. Even people who already care deeply about effectiveness tend to make better decisions when they've locked in.
It helps create a cultural norm of serious giving. Perhaps most importantly, pledging helps change what's considered "normal." We are strongly influenced by what we see others doing. When giving (especially significant, effective giving) stays private and informal, it can feel unusual or exceptional. Public pledges counteract that. By adding your name to a growing list of pledgers, you help signal that donating a meaningful share of income is both achievable and expected for those who can afford it. You don't need to talk publicly about your pledge to have this effect—simply being part of the movement adds credibility and momentum. It's easier to join a movement of 10,000 than 100. Those small signals compound into real cultural change, and that change leads to more giving, by more people, over time.
In short: even if you're already giving 10%, pledging tends to lock in your commitment, improve the quality of your giving, and amplify your impact by helping generosity become the norm rather than the exception.