General Principles

Calculations are deterministic and based on standard financial formulas.

UK tax parameters (allowances, bands, Section 24 treatment, dividend and CGT rules) are taken from current HMRC rates.

No personal data is stored on our servers for core tool use.

Results are illustrative and do not constitute financial, tax, or investment advice.

Engine Methodology Summary

Compound Interest Engine

Future value of an initial principal with regular contributions, adjustable compounding frequency, and optional annual step-up in contributions. Standard compound interest formula applied. Inflation adjustment (when enabled) converts nominal results to real purchasing power.

FIRE Matrix

Net-worth target and timeline based on desired annual spending and a chosen safe withdrawal rate. Supports Lean, Standard, and Fat FIRE scenarios.

Debt Payoff Engine

Compares Avalanche (highest interest first) and Snowball (lowest balance first) methods. Calculates total interest paid and time to clear all liabilities under each strategy.

Property / Buy-to-Let Yield

Gross and net yield, cash-on-cash return, and debt service coverage. Section 24 interest restriction modelled for basic-rate and higher-rate taxpayers. Stamp duty and cash-to-complete estimates included where relevant.

Tax Drag & ISA / GIA Optimiser

Side-by-side projection of an identical investment held in a Stocks & Shares ISA versus a General Investment Account, applying current dividend tax and capital gains tax rules and allowances.

Emergency Fund / Runway Matrix

Liquid capital required based on fixed and variable monthly burn rates, with adjustable risk buffer.

Billable Rate Engine

True minimum hourly rate after accounting for non-billable time, overheads, tax, and paid time off.

Break-Even Engine

Unit volume and revenue required to cover fixed and variable costs and reach operating profitability.

Dividend / Salary Splitter

Models the tax outcome of different salary and dividend combinations for a limited company director under current UK rates and thresholds.

Current Verification Dates

HMRC Parameter Audit

Tax Year 2026/27 Verified
  • All engines last verified: Tax year 2026/27
  • Section 24, dividend allowance, CGT annual exempt amount, and income tax bands checked against current HMRC published rates
  • Next scheduled review: April 2027 (or sooner if mid-year rule changes occur)

Important Disclaimer

These tools are provided for informational and educational purposes only. They do not constitute financial, tax, or investment advice. Always verify figures against official sources and consult a qualified professional for decisions that affect your finances.