Methodology & sources

How the numbers work

Pennies To Them scales a billionaire's donation down to your own money. Here's exactly how, and what to keep in mind.

The math

We work out what share of their fortune the donation is, then take the same share of your money.

ratio       = donation ÷ their net worth
your number = ratio × your salary (or net worth)

Worked example

• Their net worth: $400,000,000,000
• Donation: $25,000,000
• Ratio: 0.0000625 (0.00625%)
• Your salary: $75,000
• Your number: 0.0000625 × $75,000 = $4.69

All of this runs in your browser. The salary or net worth you type is never sent anywhere. See the privacy page.

Salary or net worth?

Comparing to your net worth (everything you own minus everything you owe) is the like-for-like comparison, since a billionaire's figure is also a net worth. We use salary by default because most people know it off the top of their head, and because many people's net worth is small or below zero. Using salary makes the gap look smaller than it really is.

Where the billionaire data comes from

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The list is updated once a month from Forbes' real-time figures. Before new figures are published they're checked: exactly ten people, no duplicates, every figure above $10 billion, and any figure that changed by more than half since the last update is double-checked by hand. The previous month's figures are kept as a backup.

Caveats

• Billionaire net worth is an estimate. Most of it is shares in companies, valued at their market price.
• Share prices move every day, so a net worth can swing by billions in a week. Our figures are a monthly snapshot.
• Selling a large stake would likely move its price, so the paper value isn't the same as cash in hand.
• Different publishers estimate differently, so you'll see different numbers elsewhere.

Currencies

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Donation amounts ($1M, $25M, $100M, $1B) are always in US dollars, since that's how billionaire donations are usually reported. Your salary or net worth is in the currency you select. For the math, the donation and their net worth are both converted into your currency at the same rate, so the share of their fortune stays the same whichever currency you pick.

Everyday item prices

To make the result easier to picture, we compare it to everyday things. We picked items whose prices are fairly stable and left out anything that swings a lot, like gas. These are rough typical prices, not exact ones. Prices vary a lot by city and country, especially for tuition and houses.

Photo credits

Photos come from Wikimedia Commons and are used under the licenses shown. They're stored on this site, not loaded from elsewhere. Where no free photo is available, we show initials instead.

Independence

Pennies To Them is an independent project. It isn't affiliated with, or endorsed by, any person listed or any data publisher.