100 Envelope Challenge: Rules, Totals and Easier Versions

The 100 envelope challenge turns saving into a game. You need 100 envelopes, a pen and a place to keep them. By the end you'll have $5,050.

The rules

1. Number 100 envelopes from 1 to 100.
2. Shuffle them and put them in a box.
3. On each savings day, draw one envelope at random.
4. Put in cash equal to the number on the front, then seal it.
5. Repeat until every envelope is full.

Why the total is $5,050

Add every number from 1 to 100 and you get 5,050. There's a shortcut: multiply 100 by 101, then divide by 2. The same formula works for any number of envelopes, which makes it easy to design a smaller challenge.

How long it takes

Social media posts often show the challenge done in 100 days. That pace averages $50.50 a day, or roughly $1,515 a month. For most households that isn't realistic.

Two envelopes a week is a better fit. You finish in 50 weeks and save about $101 a week on average. One a week takes just under two years.

Easier versions

Half size. Put in half the number on each envelope. You save $2,525.

Fifty envelopes. Number them 1 to 50 and save $1,275. Two a week gets you there in 25 weeks.

Cashless. Skip the paper. Use the 100 envelope challenge tracker to pick a random number, transfer that amount to savings, and tick it off.

Three mistakes to avoid

Starting without a goal. Decide what the money is for before you begin. A named goal keeps you going in week 30.

Keeping a pile of cash at home. Sealed envelopes can get lost or stolen, and cash earns nothing. Deposit the money regularly and keep the envelopes as a scorecard.

Refusing to redraw. If you pull number 96 the week your car needs work, put it back. Draw a smaller one and stay in the game.

Is it right for you?

The challenge suits you if you enjoy a bit of surprise and your spare cash varies week to week. If you'd rather know the exact amount in advance, the 52 week savings challenge follows a fixed schedule.