Save-Up / Piggy Bank Calculator

See how a fixed weekly deposit grows a small cash goal, without assuming interest or investment returns.

Quick Answer

For a $200 goal with $20 already saved, $15 each week reaches the goal after 12 deposits. The final deposit may be smaller if you stop exactly at the target.

Remaining = goal − starting amount; weekly deposits needed = ceiling(remaining ÷ weekly saving)

This is a simple cash/deposit tracker. The first weekly deposit occurs one week after the start date. No interest, fees, withdrawals, or missed deposits are modeled. For a monthly deadline and interest-based plan, use Savings Goal Calculator.

Weekly deposits to reach goal
Enter a goal

Your piggy-bank plan appears after calculation.

Still to save—
Projected goal date—
Last deposit needed—
Steps

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    How to use the piggy-bank calculator

    Enter a target amount, the cash already saved, how much you plan to add each week, and a start date. The calculator counts whole weekly deposits required and projects the date of the last deposit. It also shows the smaller final deposit that would hit the target exactly.

    This page is for a fixed weekly cash-saving habit. The Savings Goal Calculator handles a broader dated goal; the Emergency Fund Calculator starts from essential monthly expenses.

    Weekly save-up formula

    Subtract the starting amount from the goal, floored at zero. Divide the remaining amount by the weekly deposit, then round up to a whole number of weeks. If 12 deposits of $15 would add $180, the twelfth deposit lands 12 weeks after the chosen start date. This assumes deposits happen regularly at the end of each week.

    Example: saving $15 a week for a $200 goal

    With $20 already in the piggy bank, $180 remains. At $15 per week, 12 deposits are needed. If saving starts October 1, 2026 and the first deposit is one week later, the twelfth is due December 24, 2026. All 12 deposits are $15 in this example.

    What if you miss a week or change the amount?

    Update the saved amount and start date to refresh the plan. A missed week shifts the projected finish date unless you contribute extra later. Keep your goal and deposit amount realistic against regular expenses. If a goal is already funded, the calculator reports zero additional weeks rather than requiring another deposit.

    Save-Up Calculator FAQs

    Does it include bank interest?

    No. It tracks cash plus fixed weekly contributions only.

    When is the first deposit?

    One week after the start date you enter.

    What if I already have enough saved?

    The remaining amount and required deposits are zero.

    Can I change weekly deposits?

    Yes. Enter a new fixed weekly amount and recalculate. Variable deposits are not modeled.

    Editorial review

    SolverCalc names Prof. Dr. Khalil Mudassar as its educational reviewer. The formulas and examples on this page follow the references below.

    Sources

    View references

    Disclaimer

    This educational arithmetic tool is not financial advice. It assumes the same deposit every week and no interest, fees, or withdrawals.