CalculatorsSwitch calculator
How this works
In the classic 52-week challenge you save £1 in week one, £2 in week two and so on, up to £52 in week 52. Each week you save a little more than the last.
The calculator lets you change the starting amount and how much it goes up by each week. Week k saves the week-one amount plus the weekly increase times (k − 1), and it adds up the running total and the biggest single week. You can also run it in reverse, starting with the biggest week.
What it assumes
- Counting down saves exactly the same total, just in reverse order.
- Interest isn’t included. Keeping the pot in an easy-access account adds a little on top.
- There are exactly 52 weeks.
Worked example
The classic challenge and a doubled version
- Starting at £1 and adding £1 a week, you save £1,378 by week 52. That’s £26.50 a week on average.
- Halfway, at week 26, you’ve saved £351. Most of the total comes in the second half.
- Start at £2 and add £2 a week and you save £2,756, with a biggest week of £104.
- Prefer the same every week? A flat £5 a week gives £260.
Worked out with the same maths as the calculator above.
What to do next
Common questions
Is the reverse version easier?
For many people, yes. You start with the biggest weeks, often in January when motivation is high, and finish with small amounts around Christmas, when money is usually tightest.
What if I miss a week?
Just catch it up when you can. The total is what matters, not a perfect record. Some people swap weeks around to fit bigger amounts into months with more spare money.
When should I start?
Any week works. Starting in January lines it up with the calendar year, but you can start today and finish in 52 weeks’ time.
Where should I keep the money?
A separate easy-access savings account or cash ISA, so it earns interest and isn’t mixed with your spending money.