Savings interest calculator

Szybkie-Kalkulatory.pl

Choose monthly compounding savings or a deposit with one payment based on exact dates. In date mode, enter the contractual 365/366-day basis; compare early termination and retained interest. Monthly top-ups earn from the selected payment time.

Result

£10,412.60

final capital

Deposit end in monthly model2027-09-30

Total deposits£10,000.00

Gross interest£509.39

Tax on interest£96.78

Net interest£412.60

Effective rate of return4.13 %

Monthly model: tax at the selected time; a partial interest period is settled at the end. Check contract top-ups, actual days and bank tax rounding.

Capital and contributions over time

Date	Total deposits	Balance	Net interest
2026-09-30	£10,000.00	£10,000.00	£0.00
2026-10-30	£10,000.00	£10,033.75	£33.75
2026-11-30	£10,000.00	£10,067.61	£67.61
2026-12-30	£10,000.00	£10,101.59	£101.59
2027-01-30	£10,000.00	£10,135.68	£135.68
2027-02-28	£10,000.00	£10,169.89	£169.89
2027-03-30	£10,000.00	£10,204.22	£204.22
2027-04-30	£10,000.00	£10,238.66	£238.66
2027-05-30	£10,000.00	£10,273.21	£273.21
2027-06-30	£10,000.00	£10,307.88	£307.88
2027-07-30	£10,000.00	£10,342.67	£342.67
2027-08-30	£10,000.00	£10,377.58	£377.58
2027-09-30	£10,000.00	£10,412.60	£412.60

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How is it calculated?Formula, worked example and sources

How is it calculated?

Enter values

Enter your values in the visible fields.

Choose assumptions

Check the mode, units and applicable year or date.

Check the breakdown

Read the result, components and model limitations.

Compare the scenario

Change one assumption while keeping the comparison basis the same.

monthly interest = balance after opening deposit × annual rate ÷ 12balance after credit = balance + period interest − tax at creditfinal balance = balance after last period − any final tax

date mode: interest = principal × annual rate × sum(period days/year basis); early termination multiplies accrued interest by the retained percentage

Worked example

£10,412.60 final capital

Worked example using the form's default values.

Inputs: Initial principal: 10,000 PLN, Annual interest rate: 5 %, Savings term: 12 months, Compounding: monthly.
Deposit end in monthly model: 2027-09-30.
Total deposits: £10,000.00.
Gross interest: £509.39.
Tax on interest: £96.78.
Main result: £10,412.60 final capital.

Frequently asked questions

Jak czytać wynik i wybrać wariant?

How do I compare two results?

Use the same amount, horizon, dates and cost basis. Check whether the result is monthly or annual and what it includes. The comparison does not select offers or guarantee their availability.

Does a saved result recalculate itself?

A save is a snapshot. Load and recalculate it explicitly; the original remains a separate save. Check year, dates, units and assumptions before comparing.

What does unreachable or undefined mean?

A condition needed for the ratio or goal is missing. Correct the indicated value; do not treat this state as a favorable zero result.

Where do rates and assumptions come from?

Sources, retrieval dates and the next review are in the methodology. You enter prices, returns and forecasts. The calculator does not fetch offers or confirm individual eligibility.

Got an idea for this calculator?

Enter values

Enter your values in the visible fields.

Choose assumptions

Check the mode, units and applicable year or date.

Check the breakdown

Read the result, components and model limitations.

Compare the scenario

Change one assumption while keeping the comparison basis the same.

monthly interest = balance after opening deposit × annual rate ÷ 12balance after credit = balance + period interest − tax at creditfinal balance = balance after last period − any final tax

date mode: interest = principal × annual rate × sum(period days/year basis); early termination multiplies accrued interest by the retained percentage

£10,412.60 final capital

Worked example using the form's default values.

Inputs: Initial principal: 10,000 PLN, Annual interest rate: 5 %, Savings term: 12 months, Compounding: monthly.

Deposit end in monthly model: 2027-09-30.

Total deposits: £10,000.00.

Gross interest: £509.39.

Tax on interest: £96.78.

Main result: £10,412.60 final capital.

Frequently asked questions

Jak czytać wynik i wybrać wariant?

How do I compare two results?

Use the same amount, horizon, dates and cost basis. Check whether the result is monthly or annual and what it includes. The comparison does not select offers or guarantee their availability.

Does a saved result recalculate itself?

A save is a snapshot. Load and recalculate it explicitly; the original remains a separate save. Check year, dates, units and assumptions before comparing.

What does unreachable or undefined mean?

A condition needed for the ratio or goal is missing. Correct the indicated value; do not treat this state as a favorable zero result.

Where do rates and assumptions come from?

Sources, retrieval dates and the next review are in the methodology. You enter prices, returns and forecasts. The calculator does not fetch offers or confirm individual eligibility.

How is it calculated?

Enter values

Choose assumptions

Check the breakdown

Compare the scenario

£10,412.60 final capital

Frequently asked questions

Useful alongside this calculator

Savings interest calculator

How is it calculated?

Enter values

Choose assumptions

Check the breakdown

Compare the scenario

£10,412.60 final capital

Frequently asked questions

Useful alongside this calculator