compound

Compound interest calculator with beautiful terminal output.

Installation

# Clone the repository
git clone <repo-url>
cd compound

# Install with rich output support (recommended)
pip install -e ".[rich]"

# Or install without rich (plain ASCII output)
pip install -e .

Usage

# Basic: $10,000 at 7% for 10 years
compound 10000

# Custom rate and duration
compound 10000 -r 8% -t 30

# With monthly contributions
compound 50000 -r 7% -t 20 -c 500

# Different compounding frequency
compound 10000 -r 6% -t 10 -n quarterly

# Export to JSON
compound 10000 -o json > results.json

# Export to CSV
compound 10000 -o csv > results.csv

# Plain ASCII output (no colors)
compound 10000 -o plain

# Quiet mode (final amount only)
compound 10000 -q

Options

Flag	Default	Description
principal	(required)	Starting amount
-r, --rate	7%	Annual interest rate
-t, --time	10	Duration in years
-n, --compound	monthly	Compounding frequency
-c, --contribution	0	Regular contribution amount
--contribution-freq	monthly	Contribution frequency
-o, --output	rich	Output format: rich, plain, json, csv
--no-chart	—	Hide sparkline chart
--no-table	—	Hide year-by-year table
-q, --quiet	—	Show only final amount

Example Output

╭─────────────────────────────────────────────────────────────╮
│  COMPOUND INTEREST PROJECTION                               │
│  $10,000 → $19,671.51 over 10 years @ 7% (monthly)          │
╰─────────────────────────────────────────────────────────────╯

Total Interest       $9,671.51
Effective APY           7.23%
Doubling Time       9.9 years

Growth: ▁▂▂▃▄▄▅▆▇█  +96.7%

Year │   Balance   │  Interest  │  Growth  │ Cumulative
─────┼─────────────┼────────────┼──────────┼────────────
   1 │  $10,723.00 │    $723.00 │   +7.23% │    $723.00
   5 │  $14,176.25 │    $954.93 │   +7.23% │  $4,176.25
  10 │  $19,671.51 │  $1,325.39 │   +7.23% │  $9,671.51

License

MIT