A feature filled WordPress interest calculator

Slider Settings

The main plugin settings page has a number of components.
To change the settings go to Settings > Interest Calculator or Plugins > Quick Interest Slider > Settings

Form Header

Adds an H2 to the top of the form


The currency settings let you chose the symbol you want to use, if it goes in front of or behind the amount and how you indicate thousands.

Currency Selector and FX

You have two options. The first just displays the amounts in a range of selectable currencies. The second option displays the output in a selectable curries with the exchange rate calculated using the European Central Bank daily rates.

Amount Slider

If you have the pro version you can add a label to the slider and a tooltip with help information. If not you only have the option to edit the minimum, maximum, initial and step values. Only use numbers, anything else and the plugin may stop working.

Term Slider

If you want to set a period for the length of the loan or whatever check the box to enable this slider. If you have the pro version you can add a label to the slider and a tooltip with help information.

You can set the loan period and minimum, maximum, initial and step values.

The plugin is translation ready but you may want to add your own labels for singular and multiple periods.

Input Options

Whilst this is primarily a slider plugin you can offer the option for text inputs with the slider or remove the sliders completely and just have an input box.


Lets you subtract a downpayment from the loan amount before calculating the interest and repayments

Interest Rate Settings

This is where it get fun. If you only have one interest rate then you just need to set the primary. Leave everything else blank.

If you have different interest rates for different periods or amounts, fill in the table accordingly.

You now need to set the interest rate type. If you are not sure which one to use here is an explanation of the different interest rate types.

If you don’t want to use APR uncheck the box. More about APR.

The repayment divider allows you to have a slider in years but repayment in months (or some other combination). You just need to add the divider value. For example: monthly repayments on a yearly loan has a divider of 12.

Interest Rate Slider and Selectors

A pro-version option, this lets you add an interest rate slider. This replaces the interest rate triggers. The settings are similar to the amount and term sliders.

You also have the option to display an interest rate selector instead of the slider.


If you want to add a processing fee to the loan amount check the box and set the options accordingly. Depending on the version you have installed you may see options for when the processing fee is added.


Another fun section.

The default is to display the amounts and terms above the slider. The moving bubble puts the amount and term in a bubble that moves with the slider. It can spill over the width of the form if it’s a large number so check what it looks like on small screens.

The second default is to display the min and max amounts and terms above the slider. Uncheck this to only display the current amount and term.

You can choose to hide the labels and add step markers.

Beneath the slider you can add a paragraph with repayment information. There are a number of shortcodes you can use:

[repayment] – how much is to be repaid each period

[step] – the amount blocks that can be selected

[rate] – the current interest rate (uses the rates set in the table)

[interest] – the total interest to be pay

[processing] – the processing fee

[total] – the total to be repaid

[princple] – the loan amount

[term] – the loan length

[date] – the date the loan matures. There is an option to display the date as MDY or DMY

The pro version lets you add a label to the slider and a tooltip with help information.

Beneath the repayment information (if used) you can display a line with the Total to be repaid. This uses the [total] shortcode but you can add others if you wish.

All the output information can be displayed with or without decimals.

If you have sliders with an initial value of zero or are using text inputs with the same you can hide the outputs until there is a input greater than zero.


The ‘Apply now’ button is a pro options. All this does is gather the form data and pass it on to a URL of your choice for further processing. You have the option to append the form data to the URL.

If you want a simple application form this is available in the pro version. See application form settings.

  1. Julia on 04 Mar 2020:

    We provide regulated consumer credit under UK legislation. So the APR must be shown and must be accurate
    Our finance terms are:
    – interest calculated on a flat rate
    – first payment 2 months after signing (so finance repayable by 36 monthly payments has a term of 37 months)
    – £100 fee with last payment
    Would your slider be able to accommodate these terms, and would it be able to calculate an accurate APR (which is affected by the month without a payment and the fee with the last payment)

    Reply to Julia

    • Graham on 04 Mar 2020:

      Hi Julia,
      What you ask for isn’t complicated to do but it’s not part of the standard plugin. I can build you a bespoke version that has your exact term conditions with repayments.

      Reply to Graham

  2. Ondřej Holoubek on 06 Feb 2020:

    Hi Graham,
    our calculator doesnt show the correct numbers. We have annual interest rate 6% + application fee 5000 Kč. We have checked all your suggestions and the discussion bellow, but the calculator still doesnt count properly. Can you please help us?
    Our loan is 100 000 Kč, loan term is 7 years (84 months), interest rate 6%, APR 7,8%, application fee 5000 Kč, total amount payable 127 724, monthly repayment 1461 Kč.

    Reply to Ondřej Holoubek

    • Graham on 06 Feb 2020:

      You are using compound interest. Repayments usually use amortization, this is why the numbers are wrong.

      Reply to Graham

  3. Brad McQueen on 31 Jan 2020:

    How do I set the defaults of sliders once someone lands on the page?

    Reply to Brad McQueen

    • Graham on 03 Feb 2020:

      You do this in the plugin settings.

      Reply to Graham

  4. Ben on 13 May 2019:

    Ok, and the interest rate how should I settle? I want every year to get up to x 6.8%. eg the loan lasts 3 years x interest rate should be 20.4% (6.8 x 3)

    Reply to Ben

    • Graham on 13 May 2019:

      If the interest is added annually you need the term slider to be in years. You can’t have an annual rate and months on the slider if you are using simple interest. The numbers don’t work.

      Reply to Graham

  5. Ben on 13 May 2019:

    I want to set a loan, its parameters: 120 months annual interest rate 6.8%
    Installment amount in a month.
    How can this effect be achieved?

    Reply to Ben

    • Graham on 13 May 2019:

      Check the APR box and set the repayment divider to 12. This should work.

      Reply to Graham

  6. Joe on 23 Apr 2019:

    Hi Graham,
    great plugin!
    Some minor issues:
    If I enter a “.” for “Date Separator”, it won’t show up.
    For the currency I can’t choose “.” as “Thousands Separator” and “,” to separate the decimals like it’s common in Germany (e.g. 10.000,00 €). It would be great if this could be set!
    where can I find the invoice for my purchase?
    Best Joe

    Reply to Joe

    • Graham on 23 Apr 2019:

      Hi Joe,
      I’ll fix the date separator bug. Not sure about the decimal in the amount, I thought I’d fixed this.

      PayPal should have issued a receipt for your payment.

      Reply to Graham

  7. Victor on 08 Apr 2019:

    Hello, I would like to know how to put the shortcode for the different simulators, I do not see anywhere how to put them.

    Reply to Victor

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