Question 1

How is compound interest calculated?

Accepted Answer

Compound interest formula: A = P × (1 + r/n)^(n × t), where P is principal, r is the annual interest rate (decimal), n is the compounding frequency per year, and t is the time in years. For continuous compounding, A = P × e^(r × t). The Worthmap compound interest calculator supports five compounding frequencies (annual, semi-annual, quarterly, monthly, daily) plus continuous, and adds regular contributions on top of the base principal.

Question 2

How much does a 1% improvement in annual return matter long-term?

Accepted Answer

Massively, due to compounding. A $10,000 investment at 5% over 30 years grows to about $43,200. The same $10,000 at 6% over 30 years grows to about $57,400 — a 33% larger ending balance from a single percentage point. Across larger portfolios and longer horizons, the difference between 8% and 9% can compound to hundreds of thousands of dollars. This is why low-fee index funds and disciplined value investing matter so much.

Question 3

What is FIRE and how do I use this calculator for it?

Accepted Answer

FIRE stands for Financial Independence, Retire Early. The compound interest calculator models several FIRE variants: Lean FIRE (lower expense baseline, smaller target portfolio), Fat FIRE (higher lifestyle, larger target), Coast FIRE (stop contributing early and let compounding finish the job), and Barista FIRE (a portfolio that covers the gap between part-time income and expenses). Use the regular-contribution input to model SIP-style monthly investing, and watch the curve to identify your Coast FIRE crossover point.

Question 4

Does the compound interest calculator support multiple currencies?

Accepted Answer

The calculator is currency-agnostic — enter your principal and contribution in any currency and the result is in that same currency. For multi-currency net worth tracking with live FX conversion, use the full Worthmap platform.

Compound Interest Calculator — Investment Growth & FIRE Planning