Habit cost calculator
Enter what the habit costs each time, how often you do it and for how many years you expect to keep it up. You get the cost per week, month and year, ten years and the lifetime total. Add a yearly return to see what the same money could grow to if you invested it each month instead.
Runs in your browser: nothing you enter is sent anywhere.
How to use it
- Enter the cost each time and how many times a day and days a week it happens.
- Enter how many years you expect to keep the habit.
- Optionally enter a yearly return to see what investing the same money could give.
How it works
Week = cost × times per day × days per week; year = 52 weeks. Month is the year divided by 12. The invested value is a monthly savings plan with monthly compounding over your years.
Worked example
A 5 coffee once a day, 5 days a week: 25 a week, 1,300 a year, 13,000 in ten years and 52,000 over 40 years. At a 0 percent return the invested value is the same 52,000.
Good to know
The result is only arithmetic on your numbers. Prices rise and habits change, so treat long totals as a rough picture rather than a forecast.
Frequently asked questions
How is the yearly cost calculated?
Weekly cost = cost each time × times per day × days per week. A year is counted as 52 weeks, a month as a twelfth of a year, and ten years and the lifetime are the yearly cost times 10 or times your years. For a 5 coffee on 5 days a week that is 25 a week and 1,300 a year.
How is the invested value worked out?
The yearly cost is split into 12 equal monthly deposits. Each earns the yearly return divided by 12 per month, compounded monthly, for the number of years you entered: deposit × ((1 + r)^n − 1) ÷ r. At a 0 percent return it is the plain total.
Is the invested figure a prediction?
No. Real returns vary and can be negative, and fees and tax are ignored. It is a what-if for comparing a steady rate, not advice. The money is also nominal: prices change over decades.
Does it work for things other than spending on coffee?
Yes, any repeated cost: takeaway lunches, a subscription, snacks or rides. Set the cost each time and how often it happens. For cigarettes there is a dedicated smoking savings calculator.