This tutorial shows how to use the 7cows savings calculator to plan deposits and savings plans — regular contributions that grow with interest into a target amount. You'll learn how to input parameters, interpret results, account for fees, and share calculations.
The calculator at 7cows.io/save/base (and the extended 7cows.io/save/ext, which adds fees) helps you answer the two questions every saver has: "how much will I have?" and "how much must I save?"
A savings plan is the mirror image of a loan. With a loan you receive money now and pay it back; with a savings plan you pay money in regularly and receive the accumulated capital at the end.
Every savings plan can be described by a few key parameters. If you know all but one, the calculator finds the missing one:
| Parameter | Description |
|---|---|
| End capital | What you'll have accumulated at the end |
| Interest Rate | The annual interest earned on your balance |
| Deposit term | How long you keep contributing |
| Regular payment | The amount you put in each period |
| Initial capital | A starting lump sum (usually 0) |
The "Find" column (radio buttons) lets you choose which parameter to calculate. By default, the End capital is calculated from the others — the most common question ("if I save X per month, what will I have?").
You save $1,000 per month for 10 years at 1% interest, starting in September 2026.
| Parameter | Value |
|---|---|
| Regular payment | $1,000/month |
| Interest Rate | 1% |
| Deposit term | 10 years |
| Initial capital | $0 |
| End capital | $126,255 (calculated) |
You contribute $120,000 over the ten years ($1,000 × 12 × 10) and interest adds the rest, bringing you to $126,255.
Now flip the question. You want $50,000 in 5 years, you can start with $2,000 today, and the account pays 1%. How much do you need to put in each month?
Set the "Find" radio to Regular payment:
| Parameter | Value |
|---|---|
| End capital (goal) | $50,000 |
| Interest Rate | 1% |
| Deposit term | 5 years |
| Initial capital | $2,000 |
| Regular payment | $778.18/month (calculated) |
The Initial capital is a head start: because $2,000 is already working from day one, the monthly amount you need is lower than it would be from a standing start.
After calculating, the panel on the left shows:
| KPI | Meaning |
|---|---|
| End capital | The total you accumulate |
| Interest received | How much of the end capital is interest (the rest is your contributions) |
| Received per $1 saved | For every dollar you put in, how much interest you get back — net of any fees |
| Effective rate | Your true annual yield, after the timing of contributions (and fees) is taken into account |
| Deposit term | The length of the plan |
The schedule shows the balance growing over time. Because contributions come in gradually and interest compounds on the running balance, the Outstanding Balance climbs to the end capital, and the final row drops to 0 — the accumulated capital is paid out to you at maturity.
Switch between Aggregated (yearly) and Monthly views, and download the schedule as CSV.
The extended calculator, /save/ext, adds two optional fees. These are money that is simply gone — they don't earn interest — but they appear in the schedule and lower your effective rate:
| Field | German term | When charged |
|---|---|---|
| Account fee | Kontoführungsgebühr | Each payment period |
| Signing fee | Abschlussgebühr | Once, at the start |
A one-off signing fee has a smaller effect on the effective rate than you might expect, because it is amortized over the whole term — the same way a mortgage arrangement fee barely moves a loan's APR. But it counts fully (negatively) in Received per $1 saved, which captures the total lifetime cost.
Set a start month (e.g. September 2026) and the schedule is laid out on the calendar, so the yearly rows carry real years. This is optional — leave it blank for a plain "year 1, year 2, …" view.
The Compounding checkbox is on by default: interest is added to your balance and itself earns interest. Turn it off to model simple interest, where interest is paid out and never compounds.
Each configuration has a unique permalink that captures every input — click the link next to "Product permalink" to copy it, or use the auto-generated QR code. Instead of describing a savings plan in words, share the link and the recipient sees the exact same result.