Mortgage analysis tool
Mortgage calculator and analysis tool (Netherlands) for anuity, linear, interest-only loans
Amortization schedule, repayments, loan profitability vs renting and investing
🇳🇱 toets hier voor NederlandsMortgage parameters (basic):
Mortgage parameters (advanced):
Here you can "test" what would happen if some parameters of the mortgage would differ.
• "Variable1" and "Variable2" fields describe the range of variability for the parameters to be tested.
Range description format: variable_name(start_value, end_value, steps)
• "Metrics" comma-separated list of variables or expressions (using variables) you would like to measure for each "tested" loan. In a simpliest case - it is just a parameter name of interest (e.g. loan_term_actual)
Outcomes of the modelling drawn on the [What-if Graph] section below.
• If you "test" one parameter - you will get a 2D plot of Metrics required. IF you "test" two parameters - you will get a 3D plot(surface) of the first metric (or expression) in the list.
• You can use "original" mortgage parameter value in expressions using _0 postfix (e.g. loan_term_actual_0).
• Probing takes time (depends on the number of steps requested), probing process starts by [Recalculate] button.
Here you can model different "entry" months for opening the loan.
• Up to 30*12 months ahead will be tested and predefined set of metrics will be extracted from these "tested" mortgages (from specific month of their lifetime).
• Modelling will stop at the moment when no mortgage will be needed to buy the house (if that moment ever comes).
Hypothetic mortgages will have different "entry" parameters:
• assets increase will be calculated according to your cash accumulation settings / bonuses etc..
• savings used for the loan downpayment will be scaled proportionally to your assets.
• house price will be scaled according to the house market growth rate.
Outcomes of the modelling will appear on the [Entrypoint Graphs] section below.
• Loan entry parameters will be plotted with entry_ prefix.
• Loan final parameters will be plotted with loan_ prefix.
• Loan intermediate metrics will be plotted with @ postfix.
LLM-based mortgage calculation and analysis assistant:
Upsides:
• it is free and can work without internet (after first being downloaded and cached in your browser).
• because it works directly in your browser - no conversational information is being sent over Internet to anywhere (any other servers).
Downsides:
• To work it needs quite a lot of RAM and CPU resources - answer generation will take noticeable time.
• It will probably NOT work in mobile environments (because of RAM constraints).
• Model being used in a small, quantized version of Phi-3.1-mini, it is quite capable for it's size but it is not as capable as bigger models.
• Model used was trained in English, it can respond in other languages but it works best in English. Therefore the Bot works best with English version of the calculator.
Bot will inevitably hallucinate and at some point will provide inaccurate or false information.
• Do not take seriously what it generates, ever. Always doublecheck facts, statements and conclusions.
• Do not make any important decisions based only on a LLM-generated content.
Purpose and functionality:
The Bot is integrated with mortgage calculation functionality on this web site - if needed it will access and change current mortgage calculation parameters.
Its primary task is to help to fill mortgage calculation parameters into the calculation tool.
If you describe your situation in a message - it will extract relevant information from the message, update relevant parameters in calculator, run calculation and then provide explanation and analysis of the outcomes.
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Additionally the Bot can:
• answer questions about this mortgage calculator: paramers available, their meaning..
• perform analysis and generate review of the current mortgage calculation.
• answer generic mortgage-related questions (e.g: "What 'mortgage term'" parameter means).
• respond to generic / non mortgage-related queries.
LLM functionality should work in latest Chrome browsers, ad blockers or spam filtering extensions may interfere with it (it can then get stuck in "Loading" status).
Help
Input values
Input fields allow entering simple formulas using arithmetical espressions.
Example of a valid input: (1+2*3)/4
Most of the input values can be "tuned": hover mouse over and scroll up/down with Shift pressed
When pointed with a mouse - tooltip for the input values will display the field's variable name (used in other formulas).
Output values
Output values calculated automatically from input values (calculated fields are disabled for manual input)
When pointed with a mouse - tooltip for the field will show the field's variable name and calculation formula.
Payments Schedule
Monthly mortgage plan
total_payment = base_payment + extra_payment + extra_payment2 + penalty
base_payment = capital_payment + interest_amt (capital payment and interest amount values depend on the mortgage type)
extra_payment - additional montlhy repayments, topped up so that total_payment not less than extra_payment_topup
extra_payment2 - additional periodic repayments.
Manual adjustments to payments Schedule
extra_payment values can be manually adjusted by clicking on the value in the payment schedule cell. Adjusted values "live" until any other parameters of the loan gets changed and loan gets recalculated.
Extra repayments
There are several repayments that can be modelled:
• Monthly repayment: fixed monthly extra repayment used for every month of the mortgage.
• Flexible periodic repayment: more flexible - period, value and starting month of the repayment can be chosen.
• there is also 2 additional flexible repayments can be set on [Extra repayments] tab
• extra_payment_topup: every month an extra repayment will be "made" automatically such that total monthly payment is not less than this value.
Extra repayment penalties
Banks usually do not like early repayments and set a limit on how much you can repay (yearly) - everything you repay on top of the limit will be penalized.
• Max extra repayment per year, % - sets that threshold (% from the original principal debt).
• Penalty for repaying more than allowed - sets the value of the penalty - % from the payment value. If this parameter set to 100 - payments will be automatically adjusted to never exceed the allowed threshold.
Profitability analysis
Using parameters from the corresponding tab you can set values of your income, bonuses expenses etc. These then will be used to calculate different mortgage effeciency metrics.
Resulting metrics will be immediately shown in the calculatable fields, also some other metrics and their dynamics during the mortgage lifetime will be plotted on the corresponding graphs section below.
Interest rates
• Overview
• ABN Amro
• ING
• Rabo Bank
Supporting links
• Rijksoverheid : checklist-woning-kopen (NL)
• Rijksoverheid : hypotheek aanvragen (NL)
• Rijksoverheid : Voordat u een appartament koopt
• Wijzer: maximale hypotheek op basis van je maandlasten (NL)
Modelling results:
Key figures:
This is an independent open-source mortgage analitics tool.
All calculations made securely, only inside your own browser.
The website uses cookies for usage statistics.
Github
If the tool helped you in decision making or saved you some time or money - please consider supporting the development.
Just like with mortgage repayments - every cent matters :)
The tool intended only for research purposes - use it at your own risk.
There is no guarantee for the quality and accuracy of the data provided.
Involve a qualified professional before making any decisions.
