Calculator Comparisons
Examples reviewed 15 September 2026. Calculated from the same engines used by the linked tools.
Each comparison sets two options against the same inputs, states every assumption in the open, and then hands over to the calculator that can run your own figures. They exist because the honest answer to most either-or money questions is "it depends on the numbers you have not told me yet", and a worked example is the fastest way to see which numbers those are.
Start with a worked example, inspect its assumptions, then follow the calculator link to enter your own figures.
- 15 vs 30 Year Mortgage: Payments, Interest and Remaining Debt
Compare a 15-year and 30-year mortgage with the same principal and rate, including payment, lifetime interest and five-year borrowing cost.
- SIP vs Lump Sum: Equal Contributions, Different Investment Timing
Compare monthly SIP contributions with an upfront lump sum, using the same total invested and explicit assumptions about returns and timing.
- Plan 2 vs Plan 5 Student Loan Repayments
Compare UK Plan 2 and Plan 5 repayment thresholds, monthly estimates and cancellation horizons with sourced 2026/27 assumptions.