Compound growth calculator
See how a balance grows when the same rate is applied every period and you add a fixed amount each time.
This is a mathematical projection, not an expected return. Real results vary from period to period and can be negative.
How it's calculated
- Each period: balance = balance × (1 + rate) + contribution.
- 1,000 at 3% for 12 periods with no contributions: 1,000 × 1.03¹² = 1,425.76.
- Growth = final balance − starting balance − all contributions.
Questions
Is this what my account will earn?
No. The calculator applies the same rate every period, which real markets never do. It shows the arithmetic of compounding, not an expected or promised return.
What is a period?
Any fixed interval — a month, a week, a year. Use the rate and the contribution for that same interval.
When are contributions added?
At the end of each period, after that period's growth. A contribution starts growing from the next period.
Can I enter a negative rate?
Yes, down to just above −100%. It shows how a balance shrinks when the same loss repeats every period.