Interest is calculated and added 52 times a year, and any weekly deposit starts compounding the week it lands. The term is in weeks, so it matches a weekly paycheck or a savings challenge without converting to years.
104 weeks = 2 years
| Week | Opening | Interest | Deposit | Closing |
|---|
The table above is the breakdown: $5,000.00 at 5.00% with a $50.00 weekly deposit reaches $10,991.72 after 104 weeks — $10,200.00 deposited and $791.72 of interest.
Weekly compounding calculates interest 52 times a year, once each week, using one fifty-second of the annual rate as the weekly rate: i = r ÷ 52. Each week's interest is added to the balance before the next week's interest is worked out.
On the default $5,000.00 at 5.00%, the weekly rate is 0.09615%, so week 1 earns $4.81 in interest and closes at $5,054.81. With a $50.00 weekly deposit on top, 104 weeks reaches $10,991.72 — $10,200.00 deposited and $791.72 of interest. The closed form for the lump sum alone, with no deposits, is $5,525.59, which is $525.59 of interest.
Every row below uses the same $5,000.00 at the same 5.00% for the same 2 years, with no deposits. Only the compounding frequency changes.
| Compounding | Final balance | Interest earned | APY |
|---|---|---|---|
| Annually | $5,512.50 | $512.50 | 5.0000% |
| Monthly | $5,524.71 | $524.71 | 5.1162% |
| Weekly | $5,525.59 | $525.59 | 5.1246% |
| Daily | $5,525.82 | $525.82 | 5.1267% |
The spread between monthly and daily compounding here is only $1.11. The interest rate matters far more than the compounding frequency.
A = P(1 + r/52)w
w is the number of weeks. This closed form covers a starting amount on its own; weekly deposits need the week-by-week walk because each one compounds only for the weeks after it lands, which is what the calculator above does for you.
This page thinks in weeks: enter a term in weeks and an optional weekly deposit, and get a week-by-week breakdown. The daily compound interest calculator instead works in any compounding frequency and a term in years, with monthly deposits by default — the better tool for comparing daily, weekly, monthly and annual compounding side by side.
Modeling a real bank account instead? The savings account interest calculator takes the APY your bank quotes directly and builds a month-by-month statement.
Interest is calculated and added to the balance 52 times a year, once each week, using one fifty-second of the annual rate. At 5.00% the weekly rate is 0.09615%, so $5,000.00 earns $4.81 in the first week and slightly more in every week after it.
A = P(1 + r/52)^w, where P is the starting amount, r the annual rate as a decimal and w the number of weeks. $5,000.00 at 5.00% for 104 weeks is 5,000 × (1 + 0.05/52)^104 = $5,525.59. Weekly deposits are added week by week on top of that, which the calculator does for you.
Marginally. $5,000.00 at 5.00% for two years reaches $5,524.71 with monthly compounding, $5,525.59 with weekly and $5,525.82 with daily, a spread of about a dollar. The APYs are 5.1162%, 5.1246% and 5.1267%. The rate matters far more than the frequency.
A lot more than the compounding does. $50.00 a week for 104 weeks on top of $5,000.00 at 5.00% ends at $10,991.72: $10,200.00 deposited and $791.72 of interest, against $525.59 of interest on the lump sum alone.
Bank accounts rarely compound weekly; most quote an APY with daily or monthly compounding. The weekly setting is useful when you save from a weekly paycheck, run a savings challenge, or model a product that charges weekly. For a savings account, the savings account interest calculator takes the APY directly.
Calculate daily compound interest with contributions and see year-by-year growth and APY.
See what your savings account earns with a monthly statement built from your APY and deposits.
Interest per day on any balance, plus the total accrued over any number of days.