Legal Rates Calculator

How To

Get clear, court ready financial calculations in seconds with the Legal Rates Calculator. Quickly work out interest, tax, and payment increases in one simple, easy to use app.

The Legal Rates Calculator brings together key legal financial tools in one place. This allows your team to reliably obtain calculations without having to leave the matter. All results are presented in clear tables that can be downloaded as Word or Excel files, making them easy to share with clients, other parties, or the court.

To download a PDF version of this article, please click here.

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The app is currently only available in select Family matters, and we are looking to expand its use across multiple matter types and areas of law.

Accessing the App in LEAP

The Legal Rates Calculator app is available within LEAP via the following steps:

Open the relevant matter in LEAP.
Make sure you're on the Details & Correspondence tab.
Find and click on the Legal Rates Calculator button in the matter toolbar.

Navigating the App

The Calculator opens in a separate window linked to the matter.

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Maximise this window by double-clicking on the top bar or clicking on the “Maximise” option in the top-right to see the full calculation screen.

The Calculator Tabs

Switch between each specialised calculator by the tabs at the top of the screen:

Tab	What it calculates
Interest (default)	Simple interest accrued on post-judgment debt.
Capital Gains Tax	Tax liability accrued on asset disposal.
Maintenance Increase	Adjustments to ordered maintenance using the ONS price index.
Net Income	Take-home pay from gross income.

Common Features

Every calculator shares a standardised interface with a set of core functions:

Details (Left Panel): Input financial information required to run the calculation.
Breakdown (Right Panel): Detailed financial analysis of the calculation results, updates after any changes.
Export (Below Breakdown): Saves calculation results into LEAP as court-ready Word/Excel documents.
Reset (Below Details): Clears all entered financial information.

Interest Calculator

This tab calculates simple interest on post-judgment debt and lump sum orders following the Judgments Act 1838. Pursuant to the County Courts (Interest on Judgment Debts) Order 1991, relevant County Court Judgments of £5,000 or more will carry interest at the prescribed rate of 8% per annum, calculated from the date of judgment until the debt is fully satisfied. Alternatively, a custom contractual rate can be applied if specified in the original claim.

Let's walk through the calculation step-by-step:

Step 1 - Details

Enter the core financial information to calculate interest.

Field	What to enter
Principal amount	The total original judgment amount as ordered by the Court.
Interest rate	Pre-filled with the prescribed Court rate of 8%, can be overridden.
Start date	The date from which interest begins to accrue.
End date	The date up to which interest should be calculated to.

Step 2 - Partial Payments (optional)

If the paying party has made any partial payments, record them in this section to reduce the principal sum. The calculator will automatically include these reductions in the running balance, ensuring interest accrues only on the remaining debt from the date of each payment.

To add a single partial payment:

Enter the payment date in the date field.
Enter the payment amount in the amount (£) field.
Click on + Record payment.

The payment will then appear in the payments list.

Recurring Payments

If the paying party has made regular payments towards the principal sum, these can be recorded by clicking on the Add recurring payments button.

Field	What to enter
First payment date	The date when the first recurring payment was made.
Amount per payment	The fixed amount paid for each recurring payment.
Frequency	How often the payments occur - Weekly, Fortnightly or Monthly.
Ends	On calculation end date - generates payments up to a specific date. After number of payments - specify a fixed count of payments.
End date	When "On calculation end date" is selected - defaults to the calculation end date from Step 1 but can be changed.
Number of payments	When "After number of payments" is selected - defaults to 12.

As you fill in the fields, a Preview section updates in real time showing each generated payment with its date and amount, along with a count of how many will be created.

Once you are happy with the preview, click Insert generated payments. All the entries will be saved and will appear in the payments list above. The recurring payments panel will close and reset, ready to be used again if needed.

Editing / deleting payments

To amend an existing recurring payment, click the pencil icon next to it. The row switches to edit mode, showing editable date and amount fields. Make your changes and click Save to confirm or Cancel to discard the changes.

To remove a payment, click the bin icon next to it. An undo notification will briefly appear at the bottom of the section — click Undo if you change your mind or clicked this in error.

Step 3 - Review Results

The results panel on the right-hand side provides an up-to-date breakdown of the interest and current balance as of the end date. When any changes are made to the previously entered information, this panel updates in real time.

Here are some key terms seen in this panel:

Total interest accrued – The total simple interest calculated for the period.
Total days – The full number of days between the calculation start and end date.
Periods – The number of calculation segments. A new period starts for each partial payment.
Principal & accrued interest outstanding – The total amount still owed after all payments and accrued interest.
Calculation notes – A reference denoting how the calculation is performed.

Step 4 - Export Results

Once the calculation has been completed, two export options appear at the bottom of the results panel.

Copy calculation - Copies a formatted table of the result to your clipboard, ready to paste.
Upload to LEAP - Generates an Excel document containing the results, directly uploads into the matter correspondence, and previews the uploaded document.
- Click on the small dropdown arrow on the right of the Upload to LEAP button to select Word, which generates a Word document, or PDF to generate a PDF document containing the results.

Here’s an example of how the uploaded file will look like once opened:

Each file is headed with the following information:

Field	Source
Firm name	The name of the firm, as listed for the user's branch.
Case number	The matter's Court case number (in Court details).
Court	The Court associated with the matter.
Applicant	The Applicant on the matter.
Respondent	The Respondent on the matter.
Acting for	The client you are acting for on the matter.
Prepared by	The staff member who exported the calculation results.
Prepared on	Today's date (the date of export).

Saved Calculations

Each calculation is automatically saved against the matter it was run from. If you close the app and reopen it from the same matter, all the previous financial information and results will be loaded automatically – no need to re-enter anything. Each matter keeps its own set of calculations.

Want to remove saved calculations? Clicking on the Reset button at the bottom of the partial payments section will clear all previously entered financial information.

Capital Gains Tax Calculator

This tab estimates the amount of tax payable on the disposal of an asset as per the Taxation of Chargeable Gains Act 1992. For the tax year 2025/26, individual taxpayers are charged at a rate of 18% or 24%, trustees and personal representatives at 24%, calculated once the annual exempt amount has been applied. The calculation provided is an indicative estimate only and does not constitute tax advice. The exported result can be signed off by a qualified tax professional. For an accurate report, identify reliefs available or obtain tax advice, please consult a qualified tax professional.

Let’s walk through the calculation step-by-step:

Step 1 - Asset Details

Enter information about the type of asset that has been disposed.

Asset name (optional) – A label identifying the asset disposed, to be included in the export.
Asset type – The type of property or asset disposed. Different reliefs can apply based on the type of asset.

Step 2 - Taxpayer Details

Enter information about who is disposing the asset and how much annual exemption they have remaining.

Taxpayer type - The type of entity disposing the asset, which controls the rate of tax applied and the total annual exempt amount available:

Taxpayer type	Tax Implications
Individual	A person disposing of their own asset. The rate applicable depends on the amount of basic rate band left on taxable income for the tax year.
Trustee	Disposing of an asset on behalf of a trust (except a trustee for disabled people). Trusts have a lower annual exempt amount than individuals, and the rate is charged at a single flat rate.
Personal Rep	Disposing of an asset on behalf of a deceased person’s estate. Has the same annual exempt amount as individuals, but like trustees, the rate is a single flat rate.

Annual exemption already fully used this tax year - Tick if the full annual exempt amount has already been used in other disposals for the same tax period.
Exemption used elsewhere – If only part of the exempt amount has been used, enter how much. This will reduce the available exemption by the entered amount. Leave blank if not applicable.

Step 3 - Financial Details

Enter the financial costs involved in obtaining the asset, and any individual’s taxable income.

Purchase price – The original cost to acquire the asset, or the market value at the time it was acquired.
Allowable costs – The expenses directly related to acquiring, improving, or selling the asset. This includes solicitor/estate agent fees, stamp duty, fixtures and fittings. Day-to-day maintenance and repairs do not qualify.
Losses – Any capital lost over previous asset disposals, that have not been applied against a gain. These reduce the gain before the annual exempt amount is deducted. Leave blank if not applicable.
Taxable income (Individual only) – Total annual income received, minus personal allowance.
- If this figure is not known, subtract personal allowance (£12570 for most, can be less due to tax rate adjustments) from the individual’s annual income.
- If annual income did not exceed the individual’s personal allowance, leave blank.
- If annual income is above £50270, enter £37700 (the maximum amount of basic rate band).

This is used to determine the amount of basic rate band left for the tax year that can be used for this
calculation.

Step 4 - Disposal Details

Enter how the asset was disposed of and how much it was disposed for.

Sale or transfer – The method of disposal. Select “Transfer to Spouse/Civil Partner” if the asset was transferred to a partner or previous partner’s name. This will display the no gain / no loss rules where transfers occur after divorce/dissolution, or up to 3 years within the current tax year after separation.
Disposal date – The date when the asset was sold or transferred. This determines which tax year's rates and allowances apply. The calculator supports dates from 6 April 2019.
Disposal price – The amount received when the asset was sold, or the market value at the time it was transferred.

When the Purchase price and Disposal price have been entered, the calculation results will appear on the right-hand side.

Step 5 - Review Results

The results panel on the right-hand side provides a breakdown of the estimated CGT liability due, based on the information provided. When any changes are made to the previously entered information, this panel updates in real time.

Here are some key terms seen in this panel:

Total CGT payable – The estimated CGT liability calculated for the asset.
Total gain – The amount of taxable profit obtained from asset disposal.
Taxable gain – The amount of taxable profit liable for CGT, after applying the annual exemption amount.
Effective rate – The overall percentage of tax applied on the taxable gain.

The rates applied have changed over time, including the higher rate for residential property disposals on 6 April 2024 and the rates for other assets in line with residential property rates on 30 October 2024.

The disclaimer notice is added at the bottom of the results, along with any applicable notices based on the entered information.

Step 6 - Export Results

Once the calculation has been completed, two export options appear at the bottom of the results panel.

Copy calculation - Copies a formatted table of the result to your clipboard, ready to paste.
Upload to LEAP - Generates an Excel document containing the results, directly uploads into the matter correspondence, and previews the uploaded document.
- Click on the small dropdown arrow on the right of the Upload to LEAP button to select Word, which generates a Word document, or PDF to generate a PDF document containing the results.

Here’s an example of how the uploaded file will look like once opened:

Each file is headed with the following information:

Field	Source
Firm name	The name of the firm, as listed for the user’s branch.
Case number	The matter’s Court case number (in Court details).
Court	The Court associated with the matter.
Applicant	The Applicant on the matter.
Respondent	The Respondent on the matter.
Acting for	The client you are acting for on the matter.
Prepared by	The staff member who exported the calculation results.
Prepared on	Today’s date (the date of export).

Saved Calculations

Want to remove saved calculations? Clicking on the Reset button at the bottom of the disposal details section will clear all previously entered financial information.

Maintenance Increase Calculator

This tab calculates the annual changes in ordered periodical payments following the Matrimonial Causes Act 1973 using the official ONS (Office for National Statistics) price index.

Let’s walk through the calculation step-by-step:

Step 1 - Indexation Details

Enter the order information to calculate indexation.

Field	What to enter
Index type	The statistic listed in the order to base maintenance order increases on. Supports CPI, CPIH, and RPI. CPI – Consumer Price Index CPIH – CPI including owner occupiers’ housing costs RPI – Retail Price Index
Monthly maintenance ordered	The original amount of maintenance listed on the order.
Date of 1st payment	The date when the first maintenance payment was due under the order.
1st Variation date	The date of the first annual variation, the point at which the maintenance amount varies.
Relevant dates for indexation	Determines which month’s ONS index data is used per variation. The order may specify a reference month of “the month 15 months before the variation date”, and this is set as the default. If the order references a different month, choose Custom – set the two reading months to set a reference month and variation month manually.

Step 2 - Review Results

The results panel on the right-hand side provides a breakdown of the indexation based on the provided information. When any changes are made to the previously entered information, this panel updates in real time.

Here are some key terms seen in this panel:

Current Indexed Amount – The amount of monthly maintenance calculated after indexation.
Total increase – The compounded percentage change from the original maintenance amount to the current indexed amount.
Variation – The label identifying each yearly period.
Start Index – The index value at the first month of the period.
End Index – The index value at the last month of the period.

The index data is sourced from the ONS (Office for National Statistics) and updated monthly. The latest published month will appear here.

Step 3 - Export Results

Once the calculation has been completed, two export options appear at the bottom of the results panel.

Copy calculation - Copies a formatted table of the result to your clipboard, ready to paste.
Upload to LEAP - Generates an Excel document containing the results, directly uploads into the matter correspondence, and previews the uploaded document.
- Click on the small dropdown arrow on the right of the Upload to LEAP button to select Word, which generates a Word document, or PDF to generate a PDF document containing the results.

Here’s an example of how the uploaded file will look like once opened:

Each file is headed with the following information:

Field	Source
Firm name	The name of the firm, as listed for the user’s branch.
Case number	The matter’s Court case number (in Court details).
Court	The Court associated with the matter.
Applicant	The Applicant on the matter.
Respondent	The Respondent on the matter.
Acting for	The client you are acting for on the matter.
Prepared by	The staff member who exported the calculation results.
Prepared on	Today’s date (the date of export).

Saved Calculations

Want to remove saved calculations? Clicking on the Reset button at the bottom of the disposal details section will clear all previously entered financial information.

Net Income Calculator

This tab calculates the amount of tax and deductions payable on gross income for the selected tax year. The take-home pay or net figure is ready for use in financial proceedings or maintenance orders. The calculation provided is an indicative estimate only and does not constitute tax advice. The exported result can be signed off by a qualified tax professional. For an accurate report, identify reliefs available or obtain tax advice, please consult a qualified tax professional.

Let's walk through the calculation step-by-step:

Step 1 - Income Details

Enter the total income received from all possible sources. Leave as £0 if not applicable.

Field	What to enter
Tax year	The financial period for the calculation. Currently supports 2024/25 to 2026/27. Defaults to the current tax year.
Earnings from employment	The total annual employment income before any deductions. Additional jobs can be added via the “Add another employment” option. When multiple jobs are added, National Insurance (NI) is calculated separately for each job. Tick Show NI as if all earnings came from one employment for an illustrative scenario to show how NI deferment/reduced rates can impact the calculation - Official guidance
Earnings from self-employment	The annual net profit from self-employment (after allowable business expenses).
Gross dividends	The total annual dividends received before tax.
Rental income	The total annual rental income.
Other income	Any other taxable income not covered above.

Step 2 - Tax Options

Control how tax are calculated.

Scottish taxpayer – Tick if the taxpayer resides in Scotland, to calculate income tax by Scottish rates.

Step 3 - Deductions

Enter any pension contributions and student loan repayments if applicable.

Field	What to enter
Pension contributor	How the taxpayer contributes to a workplace or personal pension: % of salary – as a percentage of gross employment income. Fixed amount – as a regular monetary amount. None (default) – for no pension contributions.
Percentage of salary / Contribution amount	The percentage (0-100) % - or fixed annual amount £ of contributions made.
Pension scheme	The type of pension scheme provided by the employer: Workplace pension (net pay arrangement) – Income tax is reduced, but employee NI is still charged on the full salary. Salary sacrifice – Optional, both income tax and employee NI are reduced. Note - Employer contributions are paid by the employer on top of salary separately from gross pay and have no impact on employee income tax or NI.
Student loan plans	The type of student loan repayment plan based on salary: Plan 1 – Studies started before 1/9/2012 / in Northern Ireland. Plan 2 – Studies started from 1/9/2012 to 31/7/2023. Plan 4 – Studies in Scotland. Plan 5 – Studies started from 1/8/2023. Postgraduate – Doctorate or master’s studies.
Voluntary National Insurance	Any optional contributions made to fill gaps in the NI record. Class 2 – Available when any self-employment income has been entered, and below the small profits threshold. Class 3 – Available to anyone, to help qualify for the state pension.

Step 4 - Review Results

The results panel on the right-hand side provides a breakdown of the take-home pay calculation, based on the information provided. When any changes are made to the previously entered information, this panel updates in real time.

Here are some key terms seen in this panel:

Total take-home pay – The calculated take-home pay after tax and deductions.
Total deductions – The total tax, national insurance and deductions taken from gross income.
Effective rate – The percentage of gross income taken up by tax, national insurance and deductions.
Income tax breakdown – Click to open a breakdown of the income tax calculation:

Step 5 - Export Results

Once the calculation has been completed, two export options appear at the bottom of the results panel.

Copy calculation - Copies a formatted table of the result to your clipboard, ready to paste.
Upload to LEAP - Generates an Excel document containing the results, directly uploads into the matter correspondence, and previews the uploaded document.
- Click on the small dropdown arrow on the right of the Upload to LEAP button to select Word, which generates a Word document, or PDF to generate a PDF document containing the results.

Here’s an example of how the uploaded file will look like once opened:

Each file is headed with the following information:

Field	Source
Firm name	The name of the firm, as listed for the user’s branch.
Case number	The matter’s Court case number (in Court details).
Court	The Court associated with the matter.
Applicant	The Applicant on the matter.
Respondent	The Respondent on the matter.
Acting for	The client you are acting for on the matter.
Prepared by	The staff member who exported the calculation results.
Prepared on	Today’s date (the date of export).

Saved Calculations

Want to remove saved calculations? Clicking on the Reset button at the bottom of the deductions section will clear all previously entered financial information.

Click to edit heading

If you have any questions or run into something unexpected, that is not explained in this guide, contact your firm's LEAP Administrator or reach out to the LEAP Help Centre.

Last Modified Date

13/08/2026 12:27 am

Title

Legal Rates Calculator - User Guide

URL Name

Legal-Rates-Calculator-User-Guide-UK

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