Summary
- The Assumptions tab (Active Configuration) shows every portfolio, tax rule, and inflation setting behind your simulation.
- You can edit inflation (mean and standard deviation) and tax band inflation settings directly here.
- Inheritance tax nil-rate bands are always held fixed for your whole projection, regardless of the tax band inflation setting.
What's shown
A transparent view of every assumption powering the simulation: your portfolio allocations, the current tax year's bands (region-aware — England/Wales/NI or Scotland), inflation assumptions, and withdrawal logic.
What you can edit
- Inflation — set the mean and standard deviation used each year. Each simulation year draws a random inflation rate from a normal distribution with these parameters; set standard deviation to 0% for fixed inflation.
- Tax band inflation — by default, income tax thresholds and the personal allowance stay frozen at current levels through the known freeze period (tax year 2027/28), then grow from 2028/29 in line with your assumed inflation rate. Untick to freeze bands indefinitely instead (fiscal drag).
- State Pension triple lock — on by default, growing the State Pension at CPI plus a small premium (approximating the higher of CPI, average earnings, or 2.5%). Untick for CPI-only growth.
What's always fixed
Inheritance tax nil-rate bands are never inflated, regardless of the tax band inflation setting above — they're held fixed for your whole projection. See Inheritance Tax (IHT) planning for why.