Everything runs in your browser
Calculations happen on your device using JavaScript. We do not operate a backend API for planner inputs. Results appear instantly from the numbers you enter; nothing is uploaded for processing.
UK rules and tax years
Tools that involve tax or statutory thresholds use published UK figures for the selected tax year where applicable. For example, the Take-Home Salary Calculator uses Income Tax and National Insurance bands for England, Wales, Northern Ireland, or Scotland when selected. The Student Loan Repayment Planner uses plan thresholds for the tax year you choose. The Stamp Duty Calculator uses current residential bands for England & NI, Scotland, or Wales.
Each tool page lists its own limitations. Rules change — always confirm against HMRC, the Student Loans Company, or your lender before acting on a projection.
Projections are not predictions
Long-range tools such as the Financial Profile, Retirement Planner and Compound Interest Calculator apply the growth rates and contribution assumptions you enter. The Financial Profile projects property, pension, savings, debts and cashflow over up to 30 years using those rates plus existing amortisation models for mortgages and loans. They illustrate scenarios; they do not forecast markets, salary progression, or future legislation. These tools are for planning and illustration only and do not constitute regulated financial, tax or investment advice.
Local storage
Form values and preferences (theme, reading comfort) are saved on this device, or on your Google Drive if you sync. The Savings Tracker stores account balance snapshots the same way — no interest or growth is applied; it is a history log only. You can clear local data on the privacy page or through your browser settings. See privacy and terms for cookies and analytics.
Google Drive backup is optional (cloud icon in the top bar). Sync is off by default; see privacy details.
Updates
When UK rates or tax years change, we update the relevant calculator logic and note the assumption on the tool page.
Major updates are reflected in the site sitemap lastmod dates.