Account Increase Calculator
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Reviewed by Calculator Editorial Team
Calculate how much your account balance will increase with interest or compounding. This calculator shows the final amount with clear formulas and examples.
How to Use This Calculator
To calculate your account increase, follow these steps:
- Enter your initial account balance in the "Initial Amount" field.
- Select whether you want to calculate simple interest or compound interest.
- Enter the annual interest rate (as a percentage).
- Enter the number of years the money will be invested.
- Click "Calculate" to see your final amount.
The calculator will show you the final amount after the specified time period, along with a breakdown of how the interest was calculated.
Formula Explained
This calculator uses two different formulas depending on whether you're calculating simple interest or compound interest.
Simple Interest Formula
Final Amount = Initial Amount × (1 + (Interest Rate × Time))
Where:
- Initial Amount = the starting balance
- Interest Rate = annual interest rate (as a decimal)
- Time = number of years
Compound Interest Formula
Final Amount = Initial Amount × (1 + Interest Rate)^Time
Where:
- Initial Amount = the starting balance
- Interest Rate = annual interest rate (as a decimal)
- Time = number of years
Compound interest is calculated on the initial principal and also on the accumulated interest of previous periods. This means that you'll earn interest on interest, which can lead to significantly larger returns over time.
Worked Examples
Example 1: Simple Interest
Initial Amount: $1,000
Interest Rate: 5% (0.05)
Time: 3 years
Final Amount = $1,000 × (1 + (0.05 × 3)) = $1,150
Example 2: Compound Interest
Initial Amount: $1,000
Interest Rate: 5% (0.05)
Time: 3 years
Final Amount = $1,000 × (1 + 0.05)^3 ≈ $1,157.63
Notice how compound interest results in a slightly higher final amount than simple interest for the same inputs. This difference becomes more significant with longer investment periods.
| Initial Amount | Interest Rate | Time (years) | Simple Interest | Compound Interest |
|---|---|---|---|---|
| $1,000 | 5% | 1 | $1,050.00 | $1,050.00 |
| $1,000 | 5% | 3 | $1,150.00 | $1,157.63 |
| $1,000 | 5% | 5 | $1,250.00 | $1,276.28 |
Frequently Asked Questions
- What is the difference between simple interest and compound interest?
- Simple interest is calculated only on the original principal amount, while compound interest is calculated on the original principal and also on the accumulated interest of previous periods. This means compound interest can grow much faster over time.
- How often is the interest compounded?
- This calculator assumes annual compounding. For more frequent compounding (like monthly or quarterly), you would need to adjust the interest rate and time periods accordingly.
- Can I use this calculator for savings accounts or investments?
- Yes, this calculator can be used for any account that earns interest, including savings accounts, certificates of deposit (CDs), and certain investment accounts.
- What if I want to calculate the interest for a different time period?
- You can enter any number of years in the time field. For periods shorter than a year, you can use decimal values (e.g., 0.5 for 6 months).
- Is the interest rate before or after taxes?
- The interest rate entered should be the rate you actually earn after any taxes or fees. This calculator does not account for taxes on interest income.