Back to Compound Interest Intro
11+interest-growth

Simple vs compound

Explore why simple: interest on original amount only.

In this lesson

Simple vs compound is part of Compound Interest Intro. This preview shows how interest-growth connects to everyday family decisions such as earning, saving, spending choices, goals, approvals, or parent-guided money conversations inside Progress Penguin.

Today’s money mission

Imagine this situation: Simple interest on 10000 in local currency at 10%/year after 3 years = 13000 in local currency. Compound interest (annually) after 3 years ≈ 13310 in local currency.

What you need to know

Simple: interest on original amount only. Compound: interest on principal + accumulated interest. Over time, compound interest grows exponentially while simple grows linearly.

Real-life example

Real-life money moment: You save 50000 in local currency for 10 years. Simple interest at 10%: total = 100000 in local currency. Compound interest (annual) at 10%: total = approximately 129687 in local currency.

Progress Penguin connection

Open two savings goals with the same target but different deadlines. The longer-term goal will earn more interest because each interest payment gets added to the balance and then earns further interest. Open both and look at their projected interest earned.

Activity preview

Try the money challenge

Match each key term from this lesson to its definition. The trickiest pair connects to: simple: interest on original amount only. If a match feels wrong, reread the guided explanation and try again.

Create or review a savings goal

Open your kid dashboard and create or review one savings goal with a clear name, amount, and date.

Quiz preview

Compound interest differs from simple because:

Earns interest on previous interest
Faster for the typical person
Bigger initially for the typical person
Costs less given the circumstances

Simple interest on 10000 in local currency at 10%/year after 3 years = 13000 in local currency. Compound interest (annually) after 3 years ≈ 13310 in local currency. What is the difference and where does it come from?

No difference — both are 10%
310 in local currency extra from compound — interest earns interest on itself each year
Simple earns more — it is calculated on the original amount
3000 in local currency extra from compound