Methodology
Last updated July 2026
Every number we display comes from a primary source, carries a citation, and shows the date we last verified it. Here is exactly how we source and maintain our figures.
Primary sources only
We do not use comparison-site data. Energy rates come from the Ofgem price cap; broadband and mobile from Ofcom; water from Water UK and the Consumer Council for Water; council tax from MHCLG, StatsWales and the Scottish Government; income tax and National Insurance from HMRC and the Scottish Government; and mortgage and rate assumptions from the Bank of England.
The figures we use — verified July 2026
Every headline figure below was checked against its primary source on 19 July 2026. Each links to that source so you can verify it yourself.
| Figure | Value (2026) | Primary source |
|---|---|---|
| Energy price cap (Q3 2026, direct debit) | £1,862 / year | Ofgem ↗ |
| Electricity unit rate / standing charge | 26.11p per kWh · 57.19p per day | Ofgem ↗ |
| Gas unit rate / standing charge | 7.33p per kWh · 29.04p per day | Ofgem ↗ |
| Average water + sewerage bill | £639 / year | Water UK ↗ |
| Average Band D council tax (England) | £2,392 / year | MHCLG / GOV.UK ↗ |
| Income tax: personal allowance & bands | £12,570 · 20% / 40% / 45% | HMRC ↗ |
| National Insurance (employee) | 8% then 2% above £50,270 | HMRC ↗ |
| Average broadband bill | ≈ £31 / month | Ofcom ↗ |
| Mortgage rate assumptions | Indicative — BoE base + product data | Bank of England ↗ |
How each estimate is calculated
The savings engine is deterministic — the same inputs always give the same, verifiable numbers. Nothing here is generated by the assistant; it computes from the figures above.
- Energy — your annual spend (or the capped standard-variable figure if you don’t know it) minus a representative available fixed deal, roughly 6% below the cap.
- Broadband & mobile — your monthly spend minus a representative new-customer / SIM-only deal, annualised.
- Insurance — your premium minus a typical ~20% saved by shopping around at renewal instead of auto-renewing.
- Mortgage — first-year interest on your balance at your current (or reverted SVR) rate minus an available fixed rate. Always indicative; a broker confirms.
- Compounding — the combined monthly saving grown at a modest 5% a year over 5, 10 and 25 years (an illustration, never a guarantee).
- Mortgage overpayment — a full amortisation simulated with and without redirecting your saving, showing interest avoided and months cleared early.
Everything is dated
Rates change. Each figure shows a “verified” date, and our calculators state the period they apply to — for example the current Ofgem cap quarter. When a new cap, budget or annual rate is announced, we update the underlying figures rather than the presentation.
Estimates are indicative
Household bills depend on your property, usage, tariff and circumstances, so our results are indicative illustrations, not quotes. Where we can, we let you enter your own figures — your council’s Band D rate, your car’s MPG, your actual usage — for a closer number. We label every estimate clearly and never present one as a guaranteed outcome.
Not financial advice
Our calculators and assistant provide information to help you make your own decisions. They are not financial, tax or legal advice, and we do not arrange products. Always check the current terms with the relevant supplier or a qualified adviser before acting.