Calculator inputs
Adjust any field to update results instantly
How this calculator works
Three core mechanics drive outputs: compounding cadence, tax treatment at credit events, and inflation discounting.
Monthly accrual engine
Interest accrues monthly from an annual rate converted to a monthly rate, then credits at your chosen frequency — monthly, quarterly, or annually.
Tax deducted when credited
In DIRT mode, tax is applied when interest is credited, not continuously. State savings and pension modes are treated as fully tax-free growth.
Inflation-adjusted output
Future nominal balance is discounted by your inflation assumption, then compared against total contributions to show real gain or loss in today's euros.
Calculator questions
Quick answers to common implementation and interpretation questions.
Does this include DIRT by default?
Yes. The default account type is regular savings with DIRT at 33% applied to credited interest.
Why show both nominal and real values?
Nominal shows euros on statement; real value estimates purchasing power after inflation over the same horizon.
Is break-even rate an estimate?
It is numerically solved using the same compounding and tax rules in this model to match your selected timeline and settings.
Is this financial advice?
No. This page is educational. Validate assumptions and seek qualified advice for personal financial decisions.