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https://github.com/jimurrito/loancalc
Simple Amortization Calculator and Scheduler
https://github.com/jimurrito/loancalc
amortization amortization-schedule calculator loan-calculator loancalc windows windows-forms
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Simple Amortization Calculator and Scheduler
- Host: GitHub
- URL: https://github.com/jimurrito/loancalc
- Owner: jimurrito
- Created: 2024-04-25T05:49:06.000Z (8 months ago)
- Default Branch: main
- Last Pushed: 2024-06-21T02:24:14.000Z (6 months ago)
- Last Synced: 2024-06-22T18:42:25.056Z (6 months ago)
- Topics: amortization, amortization-schedule, calculator, loan-calculator, loancalc, windows, windows-forms
- Language: PowerShell
- Homepage:
- Size: 1.72 MB
- Stars: 0
- Watchers: 1
- Forks: 0
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
Awesome Lists containing this project
README
LoanCalc
Loan Amortization tool built in Powershell. Uses the `System.Windows.Forms` classes built into C#.
> **Note:** This script only supports Windows OS, even though it supports Powershell Core.
# Getting Started
- Download from Github.
- Open a powershell session from the repo's directory.
- Right-click and select 'Run with Powershell' or run the below in a powershell session:
**Powershell Core (7.0)**
``` Powershell
pwsh .\LoanCalc.ps1
```
**Legacy Powershell (5.1)**
``` Powershell
powershell .\LoanCalc.ps1
```
This is a graphical diffrence when you run the app from Powershell core vs legacy powershell. See below for more.
# GUI
### Legacy Powershell
### Powershell Core
## Payment Schedule Generation
Data tables in Windows Forms have not been updated, thus there is no noticable diffrence between
> **Note:** The schedule is only generated when `Generate Schedule` is toggled `On`. The schedule can also be generated on its own, without the need to run `LoanCalc.ps1`. [See section on `LoanCalc_sched.ps1` for more info.](#loancalc_schedps1)
# Functionality
The app can perform the following calculations:
- [Find Monthly Payment Amount](#find-monthly-payment-amount)
- [Find Total Loan Amount](#find-total-loan-amount)
- [Find Term of the Loan](#find-term-of-the-loan)
## Find Monthly Payment Amount
Monthly payment (A) can be found with the APR, Loan term (n), and Total Loan amount (P). APR is divided by `12` to provide the Monthly Interest rate (i).
```
i * P
A = ──────────────
1 - (1 + i)^-n
```
```Math.. uwu
In this example, the total loan amount is `$1000`, the APR is `1.0%`, and the loan term is 72 months.
Monthly Interest rate:
0.833 = 0.01 / 12
P = 1000 0.000833 * 1000
i = 0.000833 ~14.32 = ──────────────────────
n = 72 1 - (1 + 0.000833)^-72
The Monthly payment is `$14.32`.
```
## Find Total Loan Amount
Total payment (P) can be found with the APR, Loan term (n), and Monthly Loan payment (A). APR is divided by `12` to provide the Monthly Interest rate (i).
```
1 - (1 + i)^-n
P = A x ──────────────
i
```
```Math.. uwu
In this example, the monthly loan payment is `$100`, the APR is `1.0%`, and the loan term is 72 months.
Monthly Interest rate:
0.833 = 0.01 / 12
A = 100 1 - (1 + 0.000833)^-72
i = 0.000833 ~$6985.43 = 100 x ──────────────────────
n = 72 0.000833
The total loan amount is `$6985.43`.
```
## Find Term of the Loan
The term of the loan (n) can be found with the APR, Total Loan Amount (P), and Monthly Loan payment (A). APR is divided by `12` to provide the Monthly Interest rate (i).
```
1 - (i * P)
log ( ─────────── )
A
n = - ───────────────────
log ( 1 + i )
```
```Math.. uwu
In this example, the monthly loan payment is `$100`, the APR is `1.0%`, and the total loan amount is `$1000`.
Monthly Interest rate:
0.833 = 0.01 / 12
1 - (0.000833 * 1000)
log ( ───────────────────── )
A = 100 100
i = 0.000833 ~11 = - ─────────────────────────────
P = 1000 log ( 1 + 0.000833 )
The term of the loan is `11` Months.
```
# Amortization Scheduling
This functionality can be achieved via two methods.
- via LoanCalc.ps1 (Toggle `Generate Schedule = On` in the GUI)
- via LoanCalc_sched.ps1
The schedule is generated based on inputs and desired calculation. This allows the schedule to forcast alternative payment plans. To achieve this, select the `# of Payments` option under `Find:`. Then ensure your desired payment is entered.
> **Note:** By default, the schedule assumes one payment per month. This, and the intervals unit of Months can not be changed as of now.
## LoanCalc_Sched.ps1
This is the core script to generate the schedule in a `System.Windows.Form` form. This script is triggered when Toggle `Generate Schedule = On` in the GUI. This section provides as example on how to run this script via command line.
```Powershell
.\LoanCalc_sched.ps1
# or
.\LoanCalc_sched.ps1 -TotalAmount 1000 -NumoPayments 72 -APR 0.01 -MonthlyPayment 100
```
Due to how the evaluation works, the schedule will ignore the Number of payments parameter `-NumoPayments` if the loan has been paid off early.
In the example above, the schedule will end after the 11th payment; not continuing until the 72 month requirement was met.