# How long would it take a pay-it-forward chain to reach 7.4 billion people?

High school teacher Joe Howard (the guy who made the "How loud would it be if all of the cats in the world meowed at the same time?" video I posted a couple of weeks ago, is back. This time, he shows how to come up with a formula to determine how long would it take a pay-it-forward chain to reach 7.4 billion people

Many people are familiar with the concept of paying forward, but how quickly can it actually spread if we commit to it? This video calculates how many layers of pay it forward would need to happen successfully for the chain to reach everyone on the planet.

## Notable Replies

1. The cynic in me needs to point out that this math also works to dissuade someone from joining a pyramid scheme. You realize quickly that there simply isn't enough people in the world to give anyone but those near the very top all the benefits.

Really regretting eating that cynic whole, BTW. The indigestion is killing me.

2. I was thinking this. It's not like the people who have received the benefit previously would be somehow visually marked, also it becomes a logistical nightmare to track down people that haven't been paid forward even among densely populated areas.

3. Hi! I made this video and this is a very valid point. I hoped that this would not take away from the fact that the acts can still spread quickly even with repeats, I'm sure calculating the probability of repeats in a certain area would be pretty complicated.

It also assumes that no layer will advance until everyone in the previous layer has connected with their 3 people, which is also highly unlikely.

4. I have been both a recipient and a giver of pay it forwards. I have even recently paid forward a kindness I received this year. You know who you are.

I have usually paid forward the kindnesses I have received multiple times over because of the impact that the loving act has had on me. At least two acts of kindness came at such crucial, hard times in my life. Not all at once, but over the years, I have thought of them and tried to act on that kindness. I'm not sure how the record keeping of it all goes. Pretty sure I'm in the red.

Maybe I'm a weirdo. You gotta factor in us weirdos who not only pay it forward, but then over and over again keep paying forward.

5. Over the course of my life at the seemingly lowest points i've had to go through i was helped out immensely by people i hardly knew. Every time. It's saved me from myself and from the circumstances i found myself in and those acts of kindness are moments i can never ever repay. The only way to even begin is to pay it forward ad-nauseum any chance i have, which i do.

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