Plain-English definitions of 30 terms you'll see on FinCalcHub calculators and in personal-finance writing across the USA, UK, and South Africa. Skim the index, or jump to a category.
Pay As You Earn — the system by which employers in the UK and South Africa deduct income tax from your salary every month and pay it directly to HMRC (UK) or SARS (SA). PAYE applies before you receive your salary, so most employees never need to file a separate annual tax return for employment income alone.
Use the Take-Home Pay Calculator →A UK payroll contribution that funds the State Pension, certain unemployment benefits, and parts of the NHS. Employees pay Class 1 NI on earnings above the Primary Threshold (currently £12,570). Employer NI is separate and paid in addition. NI contributions also build your State Pension entitlement.
The Federal Insurance Contributions Act tax — a US payroll tax funding Social Security (6.2% on wages up to the wage base) and Medicare (1.45%). Total employee FICA is 7.65%. Employers match the same amount. Self-employed people pay both sides as SE tax (15.3%).
Unemployment Insurance Fund — a South African contribution of 1% of your monthly salary (matched by the employer) capped at R177.12 a month per side. UIF entitles you to claim short-term unemployment, maternity, illness, and adoption benefits.
The amount of UK income you can earn before paying income tax. For 2024/25 the standard Personal Allowance is £12,570. It tapers away above £100,000 (reduced by £1 for every £2 over) and is gone entirely at £125,140 — giving a 60% effective marginal rate in that band.
A range of income that is taxed at a specific rate. Tax systems in the USA, UK, and SA are progressive — only the income falling inside each bracket is taxed at that bracket's rate, not your total income. Earning £1 more rarely moves your whole income to a higher rate.
The tax rate applied to the next £1 / $1 / R1 of income you earn — the rate of your highest active tax bracket. Marginal rates matter for decisions like extra work, bonuses, or pension contributions, because they tell you what fraction of additional earnings you get to keep.
Total tax paid divided by total income — your "average" rate across all the brackets your income passes through. The effective rate is always lower than your top marginal rate. Someone earning £60,000 in the UK has a 40% marginal rate but roughly 24% effective rate after the Personal Allowance and 20% band.
Interest calculated on the original principal plus all previously accumulated interest. Your interest earns interest, producing exponential rather than linear growth. The formula is A = P(1 + r/n)^(nt). Over long horizons, compound interest is the single most important factor in retirement outcomes.
Use the Compound Interest Calculator →The cost of borrowing expressed as a yearly rate, including the nominal interest plus most fees, but assuming simple (not compound) calculation. APR is required by law on UK and US credit products so consumers can compare like with like — it lets you see a 5% APR loan as more expensive than a 4.8% APR loan, all else equal.
The actual yearly return after compounding is factored in. APY is the US term; EAR is the UK / SA term. A nominal 5% rate compounded monthly produces an EAR of about 5.116%. Always compare savings products on EAR / APY rather than nominal rate.
A UK-specific version of EAR / APY required by the FCA on savings accounts so consumers can compare products on the same basis regardless of how often interest is paid. AER assumes interest is left in the account to compound. Always use AER, not "gross" or "nominal", when comparing UK savings accounts.
Your investment return after subtracting inflation — what your money will actually buy. Real return = (1 + nominal return) ÷ (1 + inflation) − 1, or roughly nominal − inflation for small rates. Always plan retirement and long-term goals in real terms.
See the Inflation Calculator →The headline rate of return before inflation. A bank advertising 6% interest, or a fund reporting 8% growth, is quoting nominal returns. For short-term goals (under 5 years) nominal returns work fine; for retirement, always convert to real returns to know what you'll actually spend.
A mental shortcut: 72 divided by your annual return is the rough number of years your money takes to double. At 6%, money doubles every 12 years; at 9%, every 8 years. Accurate within 1% for rates between 5% and 12% — perfect for back-of-envelope retirement planning.
A US employer-sponsored retirement account funded with pre-tax salary contributions. The 2024 contribution limit is $23,000 ($30,500 if you're 50+). Many employers match a percentage of contributions — that match is the highest-return investment available to most working Americans.
Use the Retirement Savings Calculator →An Individual Retirement Account — a personal US retirement account, independent of any employer. Traditional IRAs use pre-tax contributions taxed on withdrawal; Roth IRAs use after-tax contributions and grow tax-free. 2024 contribution limit: $7,000 ($8,000 if 50+). Income limits restrict Roth eligibility.
A South African personal retirement vehicle. Contributions of up to 27.5% of taxable income (capped at R350,000 per year) are tax-deductible. Returns grow tax-free until retirement. At retirement, you can take up to one-third as a cash lump sum (with favourable tax) and convert the rest into a living or guaranteed annuity.
The retirement reform that took effect on 1 September 2024 in South Africa. New contributions split: 1/3 into a Savings Pot (accessible once a year), 2/3 into a Retirement Pot (locked until retirement). Existing balances became a closed Vested Pot. The system addresses the "cash everything out when changing jobs" problem.
The UK government-provided pension paid from State Pension Age (currently 66, rising to 67 then 68). The full new State Pension for 2024/25 is £221.20 a week (£11,502.40 a year). You need 35 qualifying years of National Insurance contributions for the full amount; 10 years for any payment.
Money you (and usually your employer) pay into a pension before it's taxed as income. In the UK and SA, contributions get tax relief at your marginal rate — a £100 contribution costs a 40% taxpayer only £60 in net pay. In the USA, 401(k) contributions are pre-tax (Traditional) or after-tax (Roth).
A retirement-spending guideline derived from US historical data: withdrawing 4% of your starting portfolio in year one, adjusted for inflation each year, had a high probability of lasting 30 years. The corollary: you need 25× your annual spending invested to retire under the rule. Debated for low-yield environments but still the most-cited starting point.
The ratio of your mortgage to the property's value. A £180,000 mortgage on a £200,000 house has 90% LTV. Lower LTV (bigger deposit) unlocks better interest rates. UK lenders' best deals typically require LTV ≤ 60%; the standard tier is ≤ 75%. In SA, 90-100% bonds are common but priced accordingly.
Use the Mortgage Calculator →Stamp Duty Land Tax (SDLT) — a one-off tax paid by the buyer on UK property purchases above the nil-rate threshold. Bands stack: 0% to £250,000, 5% £250k-£925k, 10% £925k-£1.5m, 12% above. First-time buyers get relief up to £425,000 (until March 2025). Scotland uses LBTT; Wales uses LTT.
The process of paying down a loan in equal scheduled payments over time. Each payment splits between interest (on the remaining balance) and principal. Early in the loan, most of each payment is interest; the principal share grows over time. The amortisation schedule shows this month-by-month.
South African term for a home mortgage. Bonds are typically variable-rate, linked to the SA Reserve Bank's prime rate (≈11.75% in 2024). Most lenders offer prime ± 1% based on credit profile. Transfer duty applies above R1.1m; bond registration and conveyancing costs are typically 1-2% of the loan value.
A UK tax-free savings or investment wrapper. The 2024/25 annual allowance is £20,000 across all ISA types (Cash, Stocks & Shares, Lifetime, Innovative Finance). Interest and capital gains inside an ISA are completely tax-free. Lifetime ISAs add a 25% government bonus on contributions up to £4,000 per year for first-time buyers and retirement savers.
A South African account where interest, dividends, and capital gains are entirely tax-free. Annual contribution limit: R36,000; lifetime limit: R500,000. Withdrawals don't replenish your limit, so use them sparingly. Best suited to long-term, growth-oriented investments — using the wrapper on cash interest wastes its primary benefit.
A savings account that pays a noticeably higher interest rate than a standard high-street account — typically the best available rate for instant-access cash. In a rate-cutting environment, HYSA rates drop quickly; in rate-hiking environments they lag the market briefly. Ideal for emergency funds and short-term goals.
Use the Savings Goal Calculator →Cash set aside specifically for unplanned, urgent expenses — typically 3-6 months of essential expenses. The goal is capital preservation, not growth: hold it in a HYSA or money-market account, not in stocks. Self-employed people, single-income households, and those in volatile industries should aim for 6-12 months.
Use the Emergency Fund Calculator →