Methodology and data sources.
Every calculation on Pension Bible can be reproduced from public sources. This page explains where the numbers come from, the assumptions we make, and how often we update them.
What this site is
Pension Bible is a volunteer project, built to give UK pension savers a free, plain-English starting point. We are not part of any affiliate scheme, we do not take payment from providers, and we earn nothing from any link on this site.
We make best efforts to keep tax bands, statutory limits, and provider fees current — but rules and fees change, sometimes between our scheduled refreshes. If you intend to act on any figure here, please verify it against the primary source linked below before you do.
Tax year
All calculators use the 2026/27 UK tax bands unless otherwise stated. Tax bands are reviewed in April when a new tax year begins.
Sources
- Income tax bands and rates: gov.uk/income-tax-rates
- National Insurance rates: gov.uk/national-insurance-rates-letters
- Student loan thresholds: gov.uk/repaying-your-student-loan
- Pension provider fees: each provider's published fee schedule, cited and dated on the provider's page. Full dataset available at /data/uk-pension-fees.
Assumptions
- Salary calculators assume your salary is your only source of UK taxable income, and do not account for benefits in kind or dividends.
- Personal allowance is tapered above £100,000 (£1 of allowance lost per £2 of income above £100k), as per HMRC rules.
- Compound projections use a flat nominal growth rate (typically 5%) unless otherwise stated. This is illustrative — real returns will vary, and inflation will erode purchasing power.
- Scottish income tax bands differ from rUK. Calculators that quote tax flag this in their caveats.
Updates
Tax bands are reviewed every April. Provider fee data is re-verified quarterly. If you spot an error, email us at hello@pensionbible.co.uk and we'll fix it.