100 Envelope Challenge: how to save £5,050 in 100 days

Number 100 envelopes from £1 to £100, shuffle them and stack them face down. Each day, take the top envelope and put that amount aside. On day one you might save £67 and on day two £12; the randomness is what keeps it interesting. The total is always £5,050, the sum of every number from 1 to 100.

In order (the 100-day challenge). Save £1 on day one, £2 on day two and so on to £100 on day 100. The first weeks are easy, but the amounts climb steadily, and around days 60 to 70, when you are saving £60 to £70 a day, most people either push through or give up.

Reverse. Start at £100 and work down to £1. The total is the same £5,050, but the hardest days come first, while motivation is highest, and the final days cost £5, £4, £3, £2 and £1. It gets easier as you go rather than harder.

Shuffled (the envelope version). Draw an envelope, or keep a printed grid of 1 to 100 and cross off any number you can afford that day. Save big numbers on payday and small ones in tight weeks. As long as each amount is used once, you still reach £5,050.

The average day is £50.50, which is roughly £1,515 a month. If you save in order, the weekly totals look like this:

Be honest about whether you have around £1,500 a month spare. Most people do not, so pick a version that stretches you without breaking you:

• Half version: envelopes from 50p to £50, saving £2,525.
• Penny version: 1p to £1, saving £50.50. Good for building the habit first.
• Weekly version: pick two or three envelopes a week instead of one a day, so the challenge runs for months rather than 100 days.
• Ten-week version: save £10 in week one, £20 in week two, up to £100 in week ten, for £550.
• Payday loading: save the big envelopes on payday and the small ones mid-month.
• Skip and swap: if an envelope is too big today, swap it for tomorrow's, as long as every envelope is used by the end.

The days above £50 are where people drop out, so plan for them. Look ahead at the calendar: if the expensive stretch lands on a bank holiday weekend or a birthday, bank some of those amounts early in a calmer week. Saving a day in advance is fine as long as you track it carefully.

Set a daily reminder at the same time each day, tell someone what you are doing, and if you miss a day, double up the next day or catch up at the weekend rather than quitting. Colouring in a chart or crossing off numbers makes the progress visible.

You can also share it. Split each day's amount with a partner so you each save half and still build £5,050 together, or each run your own challenge and see who finishes first.

Physical envelopes have a satisfying ritual: the shuffle, the reveal, stuffing the cash inside. But cash in envelopes earns nothing and is easy to dip into. Many people keep the daily pick and move the money into a savings account instead. SYM includes the 100 Envelope Challenge: it shows today's amount, one tap logs it, and you never lose track of which envelopes are left.

Open a separate savings account or named pot just for the challenge; seeing the balance grow is one of the most motivating parts. An easy-access account lets you get at the money in an emergency. If you want to lock it away from temptation, a notice account (30, 60 or 90 days) works, as long as you will not need it urgently. Our guide to high-interest savings accounts explains how to compare rates.

Decide before you start. A specific goal makes you far more likely to finish all 100 days. Popular choices: