Investment Calculator
Project investments with contributions, fees, modeled gain tax, and inflation assumptions.
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Everything runs 100% locally in your browser. No files are uploaded to any server.
Formula
Effective annual return r converts monthly as (1 + r)^(1/12) − 1. Nominal return compounded k times converts as (1 + r/k)^(k/12) − 1. Apply entered contributions, monthly balance fees, optional final positive-gain tax, and inflation adjustment.
Worked example
An initial 10,000 at a constant 8% effective annual return over 10 years, with no additional deposits or fees, projects 21,589.25 before tax. This is a scenario rather than a forecast.
What the result means
Separately shows deposits, growth/loss, modeled balance fees, a final gain-tax assumption, and purchasing power. You can enter yearly assumed returns or compare other rates without treating them as probabilities.
How to Use Investment Calculator
Enter the requested values
Provide the inputs for this investment calculator. Use consistent units where applicable.
Read the projected investment balance
The result recalculates as you edit the inputs.
Check the investment calculator assumptions
Use the investment calculator formula and notes below to understand what is—and is not—included.
Key Features & Benefits
Formula and worked example
An initial 10,000 at a constant 8% effective annual return over 10 years, with no additional deposits or fees, projects 21,589.25 before tax. This is a scenario rather than a forecast.
Clear scope
Separately shows deposits, growth/loss, modeled balance fees, a final gain-tax assumption, and purchasing power. You can enter yearly assumed returns or compare other rates without treating them as probabilities.
Frequently Asked Questions
Can I include regular contributions?
Yes. Choose monthly, quarterly, or annual deposits and their beginning/end timing.
Does it account for a loss?
Yes. Enter an assumed return above −100%; the simplified final gain tax applies only to a positive total gain.
Does it recommend investments?
No. It models user-entered assumptions and provides no buy/sell recommendation.
Key terms
- investment calculator
- Separately shows deposits, growth/loss, modeled balance fees, a final gain-tax assumption, and purchasing power. You can enter yearly assumed returns or compare other rates without treating them as probabilities.