Calculator Hub — Every PennyWise Finance Calculator 2026/27

Every PennyWise Finance calculator

Over 30 UK personal finance calculators and decision tools, grouped by what they help you decide. All run client-side — your inputs stay on your device. All updated for the 2026/27 UK tax year.

Savings calculators

• Savings Calculator — lump-sum interest projection
• Compound Interest Calculator — long-term growth with monthly compounding
• Regular Savings Calculator — correct maturity value for a UK monthly saver
• Savings Goal Calculator — how long until you hit your target
• Emergency Fund Calculator — 3, 6 or 9-month target sizing
• Cash ISA Calculator — tax-free growth vs taxable comparison
• PSA Calculator — tax owed on savings interest
• Savings Tax Calculator — full HMRC tax breakdown

Debt calculators

• Loan Repayment Calculator — fixed personal-loan amortisation
• Credit Card Repayment Calculator — the minimum-payment trap
• Debt Snowball Calculator — smallest-balance-first strategy
• Debt Avalanche Calculator — highest-APR-first strategy
• APR Calculator — true cost of borrowing
• Balance Transfer Calculator — does the fee pay back?

Investing calculators

• Investment Growth Calculator — portfolio projection with fees
• Investment Fee Calculator — the compounded cost of fees
• Dividend Calculator — UK dividend tax 2026/27
• ISA Growth Calculator — tax-free Stocks & Shares ISA projection

ISA calculators

• ISA Calculator — allowance tracker across wrapper types
• Cash ISA Calculator — tax-free Cash ISA growth
• ISA Growth Calculator — Stocks & Shares ISA
• LISA Penalty Calculator — cost of early Lifetime ISA withdrawal
• PSA Calculator

Mortgage calculators

• Stamp Duty Calculator UK — first-time buyer, home mover and additional property bands
• Mortgage Overpayment Calculator — interest saved and years off the term
• Save vs Overpay Mortgage — which strategy wins

Tax and income calculators

• Take Home Pay Calculator — income tax, NI, pension and student loan
• PSA Calculator
• Savings Tax Calculator
• Dividend Tax Calculator
• Pension Tax Relief Calculator

Pension & retirement calculators

• Pension Pot Projection — SIPP or workplace
• Pension Tax Relief Calculator
• Workplace Pension Calculator — auto-enrolment model
• Retirement Income Calculator — target pot from desired income

Decision tools

Side-by-side modelling for the UK's most common personal-finance choices. Each shows the mathematical answer, the assumptions behind it, and the factors it does not capture.

• Save vs Overpay Mortgage
• Cash ISA vs Savings Account
• Invest vs Save
• Debt Snowball vs Avalanche
• Regular Saver vs Easy Access
• Pension vs ISA
• Lump Sum vs Monthly Investing

Where to hold your investments

For platform-led decisions covering ISA, SIPP and JISA in one place, see Best Investment Platforms UK. The two approved PennyWise partners are Hargreaves Lansdown (widest UK platform) and InvestEngine (0% platform fee on DIY ETFs).

Related PennyWise hubs

Each calculator supports a specific decision, but the wider PennyWise hubs contain the strategy context.

How our calculators work

All calculations run entirely in your browser. Your inputs are never sent to a server. See About our calculators for the methodology and assumptions behind each tool. Every calculator is updated for the 2026/27 UK tax year. For broader context, every calculator carries an explainer section, worked examples and FAQs.