Tax Tool

Household and savings

Interest tool

See what a sum grows to at a fixed annual rate. Choose simple interest, or compound it once a year or every month. It is a savings sketch, useful beside a loan calculation when you are comparing the cost of borrowing with money left invested.

Quick math0

Use this for quick arithmetic, percentages, or to check figures while filling in the main tool, without leaving the page.

Your figures

Estimate

149,083 NOK after 10 years

Future value
149,083 NOK
Interest earned
49,083 NOK
Starting amount
100,000 NOK

How this breaks down

Interest rate
4.00%
Compounding
monthly

A savings illustration. It does not subtract tax on interest or include fees.

How to use this tool

  1. Use Interest Tool for the question described above, and check that the inputs match your records and time period.
  2. Enter starting amount.
  3. Enter annual interest rate.
  4. Enter years.
  5. Enter interest is.
  6. Change starting amount, annual interest rate, years, interest is to compare scenarios, then check the units in the result.

Worked example with the prefilled values

This example shows how Interest Tool uses its starting values. Change the calculator inputs to estimate your own situation.

Starting amount
100000 NOK
Annual interest rate
4 %
Years
10
Interest is
monthly

149,083 NOK after 10 years

  • Future value149,083 NOK
  • Interest earned49,083 NOK
  • Starting amount100,000 NOK

A savings illustration. It does not subtract tax on interest or include fees.

Formula and calculation logic

Simple: future value = P × (1 + i × t)

Compound: future value = P × (1 + i ÷ m)^(m × t); m = 1 for annual or 12 for monthly compounding

Interest earned = future value − P

Simple interest each year is the starting amount times the rate. The interest is not added to the base.

Annual compounding adds each year's interest to the base before the next year. Monthly compounding does the same twelve times a year at one-twelfth of the rate.

Nothing is added or withdrawn along the way. For a monthly saving habit, use the pension savings tool.

Assumptions

  • The rate is constant. Inflation is not subtracted, so the result is in future kroner, not today's buying power.
  • Tax on interest income is not deducted. In Norway, interest is generally part of ordinary income.

Published sources

Further reading for checking current rules and information. These links are not live inputs to the tool.

Questions about this tool

Which compounding should I pick for a savings account?

Monthly is a fair illustration when the bank credits interest through the year. Check the account terms for the real crediting schedule.

Why is compound interest higher than simple interest?

Compound interest earns interest on earlier interest. The gap grows with the rate and with time.

Can I use a negative rate?

No. The page accepts zero and positive rates up to 40%.