Mortgage calculator tool for Netherlands

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features:

• Minimalistic design:
  • virtually no dependencies
  • no need to install anything for local testing / development
• Superflexible, yet to get started you only need to provide a handful of figures:
  • House sell price
  • Savings used for downpayment
  • Loan Interest
  • Loan type
• Supports 3 most popular mortgage types in Netherlands: "Annuity", "Linear" and "Interest-only"
• Adjustable additional periodic extra repayment schedules, monthly, flexible periodic repayments:
  • you can "program" a monthly additional repayment
  • you can add 3 additional periodic repayments with any periodicity and starting month
• Adjustable in-place payments (click on any cell in "extra_payment" column in the "Payments schedule"):
  • for already calculated payment schedule you can "change" any payment in-place and schedule will be recalculated from that month onward.
• Renting, income parameters for assets ROI modelling:
  • takes into account deposit rate, house market growth rate, salary and renting information to calculate monthly total assets state and final "ROI" figures
• What-if modellig provides uni- and bi-parameter mortgage modelling functionality:
  • to test different loan parameters and to find the most convenient/profitable mortgage configuration

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"What-if" modelling:

Allowes for mortgage modelling as a function of a parameter(s).

• Any adjustable mortgage parameter can be "probed" on a range of values (e.g. extra monthly repayment).
  • you'll see the parameter variable name when you hover mouse over the input field for it
• Resulting output parameters of the mortgage then plotted on the graph (e.g. actual mortgage term).

Allowes bi-parametric modelling.

• With two parameters being "tested" - target metric drawn on a 3-D surface plot (e.g. Housing assets ROI).

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hosted on github pages:

• Mortgage expense calculator, English
• Hypotheekbetalingscalculator, Nederlands

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Local development / testing:

1. clone the repo: git clone https://github.com/r0d1on/mortgage-tool
2. make changes
3. open index.html in your browser

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How to contribute:

All contributions you make are highly appreciated.

Add changes, open a pull request

1. Fork the Project
2. Create your Feature Branch (git checkout -b feature/new-amazing-parameter)
3. Commit your Changes (git commit -m 'added new loan parameter')
4. Push to the Branch (git push origin feature/new-amazing-parameter)
5. Open a Pull Request

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credits:

• uses https://github.com/plotly/plotly.js for visualisation
• inspired by https://github.com/santiago-pan/mortgage-calculator

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support:

• buymeacoffee.com/r0d1on
• patreon.com/r0d1on