Data Sources and References
Every rate, threshold, and figure used by WhatsUK calculators comes from an official UK government source. This page lists every source with direct links and last-verified dates so you can check the data yourself.
Rates last verified:
Our Data Source Policy
WhatsUK has a strict policy of using only primary government sources for all rate and threshold data. We do not rely on financial media, third-party rate aggregators, or community-contributed figures. Every number in our calculators can be traced back to a specific HMRC publication or GOV.UK guidance page.
Our rate data is stored in a single version-controlled source file that feeds every calculator on the site. When HMRC publishes new rates - typically each April - we update this file and republish all affected calculators within 48 hours. For mid-year changes (such as a change to the Bank of England base rate or an emergency Budget announcement), we update within 72 hours.
All rates below apply to the 2026/27 UK tax year (6 April 2026 to 5 April 2027) unless otherwise stated. For previous tax year rates, please contact us or consult the archived HMRC publications directly.
Source Registry
14 sources across 14 categories
| Category | Source | Data Used | Gov Body | Last Verified | Update Freq. | Link |
|---|---|---|---|---|---|---|
| Income Tax | HMRC - Income Tax rates and allowances | Personal allowance (£12,570), basic/higher/additional rate bands, marriage allowance (£1,260), blind person's allowance, personal allowance taper above £100,000 | HMRC | 21 June 2026 | Every April | gov.uk |
| Scottish Income Tax | Revenue Scotland - Scottish Income Tax rates | Starter (19% to £16,537), basic (20% to £29,526), intermediate (21% to £43,662), higher (42% to £75,000), advanced (45% to £125,140), top rate (48% above £125,140) on earned and pension income above the UK Personal Allowance (£12,570) | Revenue Scotland | 21 June 2026 | Every April | gov.uk |
| National Insurance | HMRC - National Insurance rates and categories | Class 1 employee rates (8% and 2%), employer rate (15%) above secondary threshold (£5,000), primary threshold (£12,570), upper earnings limit (£50,270), Employment Allowance (£10,500 for eligible employers), Class 4 lower profits limit, Class 2 rate | HMRC | 21 June 2026 | Every April | gov.uk |
| Corporation Tax | HMRC - Corporation Tax rates and reliefs | Small profits rate (19% on profits up to £50,000), main rate (25% on profits over £250,000), marginal relief fraction (3/200) | HMRC | 21 June 2026 | Every April | gov.uk |
| Capital Gains Tax | HMRC - Capital Gains Tax rates | Basic rate 18%, higher rate 24% for all chargeable assets. Annual CGT exempt amount (£3,000 for 2026/27). | HMRC | 21 June 2026 | Every April | gov.uk |
| Stamp Duty Land Tax | HMRC - Stamp Duty Land Tax residential rates | Standard rate bands, first-time buyer relief (0% up to £300,000, 5% to £500,000, no relief above £500,000), additional property surcharge (5%) | HMRC | 21 June 2026 | Every April | gov.uk |
| VAT | HMRC - VAT rates | Standard rate (20%), reduced rate (5%), zero rate categories, registration threshold (£90,000), deregistration threshold (£88,000) | HMRC | 21 June 2026 | Annually / ad hoc | gov.uk |
| Student Loans | Student Loans Company - Repayment thresholds | Plan 1 threshold (£26,900), Plan 2 threshold (£29,385), Plan 4 threshold (£33,795), Plan 5 threshold (£25,000), Postgraduate Loan threshold (£21,000). All at 9% / 6% rate. | Student Loans Company / HMRC | 21 June 2026 | Every April | gov.uk |
| Pension & Auto-Enrolment | The Pensions Regulator - Automatic enrolment thresholds | Minimum total contribution (8%), minimum employee contribution (5%), minimum employer contribution (3%). Qualifying earnings band lower limit (£6,240) and upper limit (£50,270). | The Pensions Regulator / DWP | 21 June 2026 | Every April | gov.uk |
| Statutory Redundancy Pay | GOV.UK - Statutory Redundancy Pay rates | Weekly pay cap (£751 from 6 April 2026), statutory redundancy calculation formula by age and years of service, 30-year cap | Department for Business and Trade | 21 June 2026 | Every April | gov.uk |
| Child Maintenance | Child Maintenance Service - Calculation formula | Gross income thresholds, percentage rates by number of children (12%/16%/19% for 1/2/3+ children), flat rate, nil rate, reduced rate rules | Department for Work and Pensions | 21 June 2026 | Annually | gov.uk |
| Mortgage & Base Rate | Bank of England - Official Bank Rate | Current Bank Rate used as the benchmark for variable mortgage rate comparisons and savings rate context | Bank of England | March 2025 | Each MPC meeting (c. 8x per year) | gov.uk |
| Inflation | ONS - Consumer Prices Index (CPI) data | Historical CPI series used for inflation calculator to show real purchasing power over time | Office for National Statistics | March 2025 | Monthly | gov.uk |
| CIS | HMRC - Construction Industry Scheme | Deduction rates: gross payment status (0%), registered subcontractor (20%), unregistered subcontractor (30%) | HMRC | 21 June 2026 | As legislation changes | gov.uk |
HMRC - Income Tax rates and allowances
Personal allowance (£12,570), basic/higher/additional rate bands, marriage allowance (£1,260), blind person's allowance, personal allowance taper above £100,000
Revenue Scotland - Scottish Income Tax rates
Starter (19% to £16,537), basic (20% to £29,526), intermediate (21% to £43,662), higher (42% to £75,000), advanced (45% to £125,140), top rate (48% above £125,140) on earned and pension income above the UK Personal Allowance (£12,570)
HMRC - National Insurance rates and categories
Class 1 employee rates (8% and 2%), employer rate (15%) above secondary threshold (£5,000), primary threshold (£12,570), upper earnings limit (£50,270), Employment Allowance (£10,500 for eligible employers), Class 4 lower profits limit, Class 2 rate
HMRC - Corporation Tax rates and reliefs
Small profits rate (19% on profits up to £50,000), main rate (25% on profits over £250,000), marginal relief fraction (3/200)
HMRC - Capital Gains Tax rates
Basic rate 18%, higher rate 24% for all chargeable assets. Annual CGT exempt amount (£3,000 for 2026/27).
HMRC - Stamp Duty Land Tax residential rates
Standard rate bands, first-time buyer relief (0% up to £300,000, 5% to £500,000, no relief above £500,000), additional property surcharge (5%)
HMRC - VAT rates
Standard rate (20%), reduced rate (5%), zero rate categories, registration threshold (£90,000), deregistration threshold (£88,000)
Student Loans Company - Repayment thresholds
Plan 1 threshold (£26,900), Plan 2 threshold (£29,385), Plan 4 threshold (£33,795), Plan 5 threshold (£25,000), Postgraduate Loan threshold (£21,000). All at 9% / 6% rate.
The Pensions Regulator - Automatic enrolment thresholds
Minimum total contribution (8%), minimum employee contribution (5%), minimum employer contribution (3%). Qualifying earnings band lower limit (£6,240) and upper limit (£50,270).
GOV.UK - Statutory Redundancy Pay rates
Weekly pay cap (£751 from 6 April 2026), statutory redundancy calculation formula by age and years of service, 30-year cap
Child Maintenance Service - Calculation formula
Gross income thresholds, percentage rates by number of children (12%/16%/19% for 1/2/3+ children), flat rate, nil rate, reduced rate rules
Bank of England - Official Bank Rate
Current Bank Rate used as the benchmark for variable mortgage rate comparisons and savings rate context
ONS - Consumer Prices Index (CPI) data
Historical CPI series used for inflation calculator to show real purchasing power over time
Update Schedule
Each data source is monitored on a different schedule depending on how frequently it changes. Income tax, National Insurance, corporation tax, and stamp duty rates are reviewed every April when the new tax year begins. Sources that change more frequently - such as the Bank of England base rate (updated at each Monetary Policy Committee meeting, roughly 8 times per year) or the ONS CPI inflation series (updated monthly) - are checked on their own schedule.
In addition to scheduled reviews, we monitor HMRC's RSS news feed and GOV.UK policy announcements for any mid-year changes. Emergency Budget announcements, supplementary guidance notes, and legislative changes are actioned within 72 hours. All updates are reflected in the "Last Verified" dates shown in the table above.
If you believe a source or rate shown on WhatsUK is incorrect or out of date, please contact us. We investigate all reports within 24 hours and correct errors immediately if confirmed.
About this registry
This source registry is maintained by James Hartley, CIMA-qualified founder of WhatsUK, and is updated after every UK Budget or HMRC announcement. If you believe a source is out of date or we have missed an official publication, please contact us. We take accuracy seriously and will investigate all reports within 24 hours.