A small donation to a local charity might help one family. But the same dollar amount could save many lives abroad - if used to help prevent malaria, for instance.
"An average of 16,000 children under the age of five die every day largely from poverty-related causes," noted Ms Wanyi Zeng, 29.
She is the co-founder of Effective Altruism Singapore, part of a global "effective altruism" movement which takes a hard-headed approach to being big-hearted.
"Effective altruism is guided by reason and global empathy," said Ms Zeng. It is finding out where your charitable dollar can have the biggest impact, even if that is overseas.
The lack of a sense of impact is why she left her job as a community worker two years ago: "I didn't feel very much like I was contributing in a meaningful way."
In contrast, effective altruism measures the impact of donor dollars, with non-profit groups such as GiveWell dedicated to this research.
The calculating approach could be a turn-off, noted Ms Zeng: "To some people, it might feel too rational, too depersonalising."
But fellow co-founder Kyle Tan, 22, thinks that Singapore's efficiency culture helps. "The 'effective' part definitely works well here," said the second-year National University of Singapore business student.
The challenge is getting people to care about the needy elsewhere - "being impartial about where you give", he added.
Ms Zeng said her experience in Singapore's social sector contributed to her global perspective.
She added: "I feel that Singapore's poverty issues cannot be addressed just by individual donations. But individual giving can have a much bigger impact abroad."
To raise awareness and grow the community, Effective Altruism Singapore - which has a team of just eight but over 100 members on its Facebook group - holds monthly meet-ups, usually on the first Sunday of every month.
In May, the group also organised a public talk on effective altruism, with Australian philosopher Peter Singer speaking via Skype, in partnership with the Humanist Society (Singapore).
The goal is to get Singaporeans to donate to proven highly effective charities, and ideally to pledge a portion of their income each month.
For now, the co-founders say their focus is on spreading the word in search of like-minded people, not persuading the unconvinced.
They will also reach out to philanthropic groups and companies, which may be keener on getting the most for their charitable buck.
And even if Singaporeans do not choose to donate to foreign causes, Ms Zeng hopes they will adopt the rational, evidence-based approach to doing good.
"I hope the culture of giving will change such that people think more about how they are giving."
Correction Note: An earlier version of the story did not mention that the public talk in May on effective altruism was organised in partnership with the Humanist Society (Singapore). This has been corrected. We are sorry for the error.