UK Financial Calculators
Every Casvia tool in one place. Free, instant, UK-specific — all calculations run in your browser and nothing is stored.
Savings & investing
UK ISA Calculator
ISA allowance, contributions and growth — including the Lifetime ISA bonus.
Open →UK Savings Calculator
How regular deposits and interest grow — with AER explained.
Open →Compound Interest Calculator
The power of compounding with different frequencies, annualised for the UK.
Open →Investment Return Calculator
Project growth, or work out the monthly saving to hit a target.
Open →UK Inflation Calculator
What money is worth over time, using CPI inflation.
Open →Tax
UK Income Tax Calculator
Income Tax on your salary or pension for 2026/27, with Personal Allowance.
Open →UK Salary Calculator
Gross to net — Income Tax, National Insurance and take-home pay.
Open →National Insurance Calculator
Class 1 employee NICs at 8% and 2% for 2026/27.
Open →Capital Gains Tax Calculator
CGT on shares and other assets — £3,000 allowance, 18%/24% rates.
Open →Dividend Tax Calculator
Dividend tax at 2026/27 rates after the £500 allowance.
Open →Mortgage & property
Mortgage Calculator
Monthly repayments, total interest and an overpayment-free balance chart.
Open →Mortgage Overpayment Calculator
How much overpayments save you in interest and time.
Open →Stamp Duty Calculator
Stamp Duty in England & NI, Scotland and Wales for 2026/27.
Open →Retirement
Pension Calculator
Your pot, contributions, tax relief and growth to retirement.
Open →Retirement Calculator
The income gap, the pot you need and the monthly saving to get there.
Open →About the numbers
Every calculator uses official UK data — GOV.UK, HMRC, the Scottish and Welsh governments, ONS and the Bank of England — with the tax year clearly stated. See Methodology for every formula and assumption.
Casvia provides educational calculators and general information. It does not provide personal financial, tax or investment advice. Rules and thresholds can change — always check the latest official guidance.