ROI Calculator

Return on investment (ROI) compares profit with the money put in, expressed as a percentage. It answers: for every £100 invested, how many pounds came back above the original stake?

ROI is widely used for equipment purchases, marketing campaigns, stock trades, and project approvals. It is a snapshot — it does not alone capture risk, cash timing, or how long capital was tied up.

Pair ROI with payback period and annualised return when comparing options with different time horizons.

ROI = (gain from investment − cost) ÷ cost × 100. It expresses profit relative to money put in — useful for comparing unlike projects on one scale.

ROI ignores time unless you add duration context — £10k return in one year beats the same return in five years.

Use with cost per feature calculator for product bets and CAC calculator for acquisition.

Invest £1,000 and receive £1,500 after one year. Profit is £500. ROI = (£500 ÷ £1,000) × 100 = 50%.

Because the period is one year, annualised ROI is also 50%. Over two years with the same final value, total ROI stays 50% but annualised ROI is roughly 22.5% — compounding means the yearly rate is lower when the same gain is spread over longer.

A 50% headline return sounds strong, but context matters: risk, liquidity, and opportunity cost of tying up £1,000 elsewhere.

Gain £15,000, cost £10,000 → net £5,000. ROI = 5,000 ÷ 10,000 × 100 = 50%.

If gain is £8,000, ROI = 30% — still positive but weaker priority versus other uses of £10,000.

Negative ROI when gain £7,000 → −30% — you lost £3,000 net on the investment.

ROI (%) = (final value − initial investment) ÷ initial investment × 100. Negative ROI means the investment lost money.

Annualised ROI uses compound growth: ((final ÷ initial)^(1 ÷ years) − 1) × 100. Use it when comparing a three-year project with a one-year campaign.

ROI % = (gain − cost) ÷ cost × 100. Gain should include all measurable returns; cost all-in spend.

Annualised ROI adjusts for time when comparing long projects.

ROI does not capture risk — two projects with same ROI may have very different uncertainty.

Prioritising marketing channels, equipment, training, or inventory buys.

When stakeholders need a common language for approve/defer/kill.

After the fact — compare planned vs actual ROI for learning.

Increase measurable gain — conversion, price, retention.

Cut all-in cost including hidden labour.

Shorten payback so capital turns faster.

Kill low-ROI spend early.

Measure so ROI is based on data not narrative.

Two projects both showing 40% ROI are not equal if one pays back in 8 months and the other in 3 years. Note duration beside ROI when presenting to stakeholders, or annualise returns for long capex.

Include staff time at loaded cost in the investment side for internal projects — a £5,000 tool spend with £15,000 of engineering time is a £20,000 bet, not a £5,000 line item.

Pair ROI with strategic fit: compliance, platform stability, or retention moats may justify sub-threshold ROI if kill criteria are documented upfront.

Counting gross revenue lift without subtracting incremental COGS or support cost — use contribution or gross profit in the gain figure when margin is material.

Attributing 100% of a revenue increase to one initiative when multiple changes happened in the same quarter — holdout groups or before/after cohorts reduce fantasy attribution.

Ignoring opportunity cost — money in a 25% ROI project cannot also earn elsewhere; rank against your next-best use of the same capital.

Rank initiatives by ROI and strategic fit — kill or defer the bottom quartile when capital is constrained even if ROI is positive.

Log planned vs actual ROI after 90 days for marketing and tooling spend — learning compounds when assumptions are written down.

Large bets should also run through cost per feature calculator or capex review if they change product or ops materially.

Document assumptions at approval — expected revenue lift, cost, and timeline — then schedule a 90-day post-launch review against actuals. ROI learning compounds when teams cannot hide behind vague "brand" benefits forever.

Use the same discount or hurdle rate across marketing, tooling, and hiring bets so committees compare apples to apples rather than championing the project with the prettiest spreadsheet.

This page should target ROI calculator, return on investment calculator, investment return percentage, project ROI, and annualized ROI searches.

It calculates profit, ROI percentage, and annualized ROI from initial investment, final value, and years. It does not calculate NPV, IRR, payback schedules, tax, risk-adjusted return, attribution, or multi-cash-flow project finance.