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Updated for FY20258 tools reviewed

The best investment calculators for 2026.

Eight tools to project compound growth, model retirement income, and compare ISAs against SIPPs — without the spreadsheet gymnastics.

Investing is one of the most effective ways to build long-term wealth, but without modelling the numbers it’s hard to know whether you’re saving enough, choosing the right vehicle, or on track for your goals.

These calculators let you project growth, compare options and make confident decisions. Each was tested for accuracy of compounding logic, realism of default assumptions, and clarity of output.

Our picks for FY2025

  1. Editor’s pick
    01

    Editor’s pick

    Compound Interest Calculator

    See how money grows over time. Enter an initial deposit, monthly contribution, interest rate and time period to see year-by-year projections.

    Year-by-year growth table
    Monthly contribution modelling
    Compare rates instantly
    Inflation-adjusted view

    Best for: Savers, new investors, and anyone wanting to feel viscerally how compounding accelerates wealth.

    Try Compound Interest Calculator
  2. 02

    Runner-up

    Investment Return Calculator

    Calculate the total return on an investment including capital gains and reinvested dividends. Shows annualised returns and total profit over your chosen period.

    Total return calculation
    Annualised return rate
    Dividend reinvestment
    Multiple time periods

    Best for: Active investors tracking portfolio performance, and anyone reviewing past returns.

    Try Investment Return Calculator
  3. 03

    Highly rated

    Savings Growth Calculator

    Project how your savings will grow with regular deposits and interest. Ideal for setting savings targets and timing big purchases.

    Goal-based projections
    Regular deposit modelling
    Rate comparisons
    Time-to-target calculation

    Best for: People building an emergency fund, saving for a deposit, or planning medium-term goals.

    Try Savings Growth Calculator
  4. 04

    Pick 4

    Retirement Savings Calculator

    Estimate how much you need for retirement and whether you are on track. Factors current savings, monthly contributions, expected returns and target retirement age.

    Retirement pot projection
    Income in retirement
    Contribution gap analysis
    Inflation-adjusted figures

    Best for: Anyone planning for retirement, from early career to those approaching the finish line.

    Try Retirement Savings Calculator
  5. 05

    Pick 5

    Dividend Yield Calculator

    Calculate the dividend yield on a stock or fund. Helps compare income-generating investments side by side.

    Yield percentage
    Annual income projection
    Compare multiple stocks
    Dividend cover assessment

    Best for: Income investors, dividend portfolio builders, and anyone comparing yields.

    Try Dividend Yield Calculator
  6. 06

    Pick 6

    ISA Calculator

    Project the tax-free growth of your ISA. Accounts for annual contribution limits and shows how much you save by avoiding tax on returns.

    Annual allowance tracking
    Tax-free growth
    Cash vs S&S ISA comparison
    Long-term wealth modelling

    Best for: UK savers and investors using stocks-and-shares ISAs or cash ISAs.

    Try ISA Calculator
  7. 07

    Pick 7

    Index Fund Calculator

    Model the long-term growth of regular investments into index funds. Uses historical averages and accounts for fund fees.

    Fee impact analysis
    Historical return benchmarks
    Regular investment modelling
    Lump sum vs drip-feed

    Best for: Passive investors, those new to index funds, and anyone comparing funds.

    Try Index Fund Calculator
  8. 08

    Pick 8

    SIPP Calculator

    Calculate projected growth of a Self-Invested Personal Pension. Factors in tax relief, growth and projects retirement income.

    Tax relief calculations
    Retirement income projection
    Contribution limit guidance
    Growth net of fees

    Best for: Self-employed workers, freelancers, and employees building additional pension savings.

    Try SIPP Calculator

Investing principles to remember

  • Start early: Compound interest rewards time in the market more than timing the market.

  • Diversify: Spread investments across asset classes to reduce risk without sacrificing return.

  • Use tax wrappers: ISAs and SIPPs let your investments grow tax-free or tax-deferred.

  • Keep fees low: Even small percentage fees compound significantly over decades.

  • Stay consistent: Regular monthly investing smooths out market volatility through pound-cost averaging.

Frequently asked

Investment calculators provide reliable projections based on the inputs you provide. However, actual returns depend on market conditions, fees, and timing. Use them for planning and comparison rather than as guaranteed predictions.

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