Our sources
How we check our numbers
Tax figures go out of date. This page explains where ours come from, when we re-check them, and when each guide was last checked.
Where the figures come from
Every rate, threshold, deadline and rule in our guides and calculator comes from official sources:
- GOV.UK guidance, such as the Income Tax and National Insurance rates pages
- HMRC publications, such as the Self Assessment forms and their notes, and HMRC’s internal manuals
- Government announcements on GOV.UK, and legislation on legislation.gov.uk
We don’t take figures from other blogs or calculators. Each guide ends with a list of the sources it relies on, linked so you can check them yourself. If we can’t confirm a figure from an official source, we leave it out.
When we review them
We aim to review these figures at the start of each tax year and whenever GOV.UK guidance changes.
Each guide shows the date its figures were last checked against GOV.UK, and an “Updated” date when its content last changed.
The calculator and the app
The side hustle tax calculator uses the same tax settings and maths as the Hamster app, copied from the app’s code, so the two can’t give different answers. It uses the 2026–27 rates for England, Wales and Northern Ireland, last checked on 25 October 2026.
Last checked
- Side hustle tax calculator
- Allowable expenses for a side hustle in the UK: what you can and can't claim
- Do you pay National Insurance on side hustle income?
- HMRC mileage rates 2026/27 for sole traders: 55p and 25p explained
- How to fill in the SA103S self-employment pages for a side hustle
- PAYE job plus side hustle: how are they taxed together?
- Self Assessment deadline 31 January 2027: what's due and what to do
- Do content creators pay tax on gifted products and brand deals?
- Does Making Tax Digital apply to my side hustle?
- How much should I set aside for tax on my side hustle?
- Is the side hustle tax threshold going up to £3,000?
- Missed the 5 October deadline to register for Self Assessment? Here's what to do
- What are payments on account, and why is my first tax bill so big?
- Do I need to pay tax on Vinted, eBay or Depop sales?
- Do I need to register as self-employed for a side hustle?
- How much tax do Uber and Deliveroo drivers pay in the UK?
- What is the trading allowance and how does it work?
What we don’t do
Our guides and calculator give general information, not personal tax advice. They explain the rules as they apply to typical side hustles; your own position can differ. For anything you’re unsure about, check the linked GOV.UK pages or speak to an accountant.
Spotted something out of date?
Tell us at hamsterapptax@gmail.com, with a link to the page and the source that disagrees, and we’ll check it.