ProsperMath guides
Understand the decision behind the number.
Worked examples, trade-offs and official sources—each connected to a calculator so you can test the assumptions yourself.
How Much Should I Invest Each Month?
Work backwards from your goal, timeframe and current savings to choose a realistic monthly investment amount.
Read guide →InvestingLump Sum or Monthly Investing: Which Approach Fits?
Compare investing available cash immediately with phasing it into the market over time, including risk and behavioural trade-offs.
Read guide →InvestingWhat Is the Cost of Waiting to Invest?
See why a five-year investing delay can change a long-term projection even when the monthly contribution stays the same.
Read guide →InvestingHow Much Can Investment Fees Cost Over Time?
Understand how a seemingly small annual fee compounds into a much larger difference over a long investment period.
Read guide →PropertyShould You Overpay the Mortgage or Invest?
Compare the guaranteed interest saving from a mortgage overpayment with uncertain investment growth and liquidity.
Read guide →DebtDebt Avalanche vs Snowball: Which Method Saves More?
Compare paying the highest-interest debt first with clearing the smallest balance first, including a worked example.
Read guide →DebtWhy Credit Card Minimum Payments Cost So Much
See how interest and a low monthly payment can extend credit-card debt, plus how to test a faster repayment amount.
Read guide →SavingsHow Much Emergency Fund Do I Need?
Choose an emergency-fund target using essential monthly costs, income stability, dependants and access to other support.
Read guide →United KingdomHow the UK ISA Allowance Works in 2026/27
Understand the £20,000 adult ISA allowance for 2026/27, the Lifetime ISA sub-limit and flexible-ISA replacement rules.
Read guide →United KingdomDividend Reinvestment in the UK: ISA vs Taxable Account
See how reinvesting dividends can compound and how UK dividend tax outside an ISA can create long-term drag.
Read guide →United StatesHow Much 401(k) Employer Match Are You Leaving Unclaimed in 2026?
Translate a 401(k) matching formula into dollars and compare it with the 2026 employee contribution limits.
Read guide →CanadaTFSA Contribution Room in 2026: Mistakes to Avoid
Understand the C$7,000 TFSA dollar limit for 2026, unused room, withdrawals and common overcontribution mistakes.
Read guide →How we publish
Examples you can reproduce.
Every guide identifies its assumptions, links to the calculator used for worked examples and cites official sources for regional limits. Guides are reviewed when rules change and clearly state their review date.