PlainISA Tools

Interactive UK ISA tools for the 2026/27 tax year. Choosing between Cash, Stocks & Shares, Lifetime, Junior, and Innovative Finance ISAs means weighing a £20,000 annual cap against very different bonus, lock-in, and risk profiles, the three tools below turn those trade-offs into concrete numbers rather than generic guidance.

• ISA Calculator - year-by-year balance projection with cap, bonus, and growth modelling. Enter a starting balance and annual contribution to see how the LISA's 25% government bonus or S&S ISA's real-return assumption compounds over time.
• Decision Engine - six-question wizard to recommend the right wrapper for your goal (house deposit, retirement, short-term saving, or a child's future) based on your age, horizon, and risk tolerance.
• Side-by-Side Comparison - all five ISA wrappers compared on allowance, bonus, lock-in, FSCS protection, and best-for fit in one table, sourced from the HMRC ISA Manager Guidance Notes.
• Cash ISA Detail · S&S ISA Detail · Lifetime ISA Detail · Junior ISA Detail · IFISA Detail - full rules, allowance, and eligibility for each wrapper type.