Compound interest
Model balance growth with a constant rate, regular deposits and a chosen compounding frequency. Drag the graph handles to change inputs and explore the result.
Your inputs
The editable example is illustrative. Enter your own dimensions, operating data, prices, and fees. Results update as you edit.
Calculations run in your browser. Inputs are not saved or sent to analytics.
How it works
- 0 ≤ k ≤
- n = 12 (Monthly), 4 (Quarterly), 1 (Annual); r = ÷ 100 ÷ n; End of period: B′ = × (1 + r) + ; Start of period: B′ = ( + ) × (1 + r)
- Worked example: 1,000 × 1.1² = 1,210; 1,000 + 12 × 100 = 2,200 (r = 0)
- Supported input limits: : 0 ≤ x ≤ 1,000,000,000,000; : 0 ≤ x ≤ 1,000; : 1 ≤ x ≤ 1,200; : 0 ≤ x ≤ 1,000,000,000,000
Input and formula key
Your result
Complete the inputs to see your result.
Assumptions and limitations
Periods follow the selected frequency, so 12 monthly periods mean one year. The entered annual rate is divided by that frequency. Deposits occur each period at the selected timing. The projection excludes fees, taxes and changing returns.
Sources
- Investor.gov — compound interest calculator Sources reviewed: 2026-10-06
- Investor.gov — savings goal calculator Sources reviewed: 2026-10-06
- CFPB — compound interest Sources reviewed: 2026-10-06
