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percentagechangecalculator.co.uk

Header — Percentage Change Calculator
About Us — Percentage Change Calculator UK
About Us

Built to make percentage math effortless.

We're a small team of developers, maths enthusiasts and finance professionals who got tired of clunky calculators, confusing results, and tools that just spit out a number without explaining how it was reached. So we built our own.

United Kingdom Live since 2024 Trusted by 50k+ monthly users 100% free, no sign-up
Our Story

From frustration to a cleaner, smarter calculator.

It started with a simple frustration. One of our founders, while reviewing quarterly investment returns, noticed that three different "percentage change" calculators on the first page of Google gave three different answers for the same set of numbers — especially when negative values were involved.

The root cause? Most calculators skip the absolute value of V₁ in the denominator, which means they break the moment your starting value is negative. That's mathematically wrong, and it misleads students, investors, and business owners every day.

So in early 2024, we set out to build the percentage change calculator we wished existed — one that is always correct, shows every step, explains edge cases honestly, and looks good doing it.

"We don't believe a calculator should just hand you a number. It should show its work, handle the weird cases, and teach you something along the way."
Our Journey
JAN 2024
The Idea
Spotting inconsistency in popular percentage calculators while reviewing investment data.
MAR 2024
First Prototype
Built a working calculator with absolute-value handling and step-by-step breakdown.
JUN 2024
Public Launch
Released percentagechangecalculator.co.uk to the public — free, no sign-up, ad-light.
SEP 2024
10k Monthly Users
Crossed 10,000 monthly active users — students, investors, analysts and small business owners.
OCT 2026
Terms Refresh & Suite Expansion
Updated Terms of Use and committed to building a family of clean, accurate percentage tools.
What We Stand For

Our Mission & Values

Our mission is simple: make every percentage calculation transparent, correct, and effortless — for everyone, everywhere, forever free.

Accuracy First

Every result is mathematically rigorous. We handle negative values, zero edge-cases, and floating-point precision the way textbooks do — not the way shortcut code does.

Full Transparency

We show the formula, every intermediate step, and the exact numbers used. You should never have to wonder how a result was reached.

Speed & Simplicity

No pop-ups, no sign-up walls, no clutter. Open the page, type two numbers, get the answer. That's it.

Education Over Output

A calculator that just gives you a number teaches nothing. We include worked examples, common mistakes, and FAQs so users walk away smarter.

Always Free

Core tools will always be free, with no paywalls, no "premium tiers" for basic features, and no selling of personal data. Ever.

Accessible Everywhere

Built mobile-first, works on every modern browser, keyboard-navigable, and screen-reader friendly. Maths shouldn't have a device barrier.

What We Built

What Our Calculator Actually Does

Not just a number — a complete, educational calculation experience.

Instant Percentage Change

Enter two values and get the percentage increase or decrease immediately — no page reload, no waiting.

Step-by-Step Breakdown

See exactly how the result was reached — difference, division by |V₁|, and final multiplication shown clearly.

Negative & Zero Handling

Correctly computes results when the original value is negative, and clearly explains the undefined case when V₁ = 0.

Clickable Example Presets

Real-world scenarios (price drops, salary hikes, population growth) auto-fill the calculator so you can see it in action.

Formula & Worked Examples

Built-in reference for the percentage change equation, plus six fully worked examples covering every edge case.

Comprehensive FAQ

Ten detailed answers covering the most common percentage-change questions, including Excel formulas and percentage-point confusion.

50K+
Monthly Users
And growing every month
1.2M+
Calculations Run
Real computations, no caching
99.9%
Uptime
Always there when you need it
£0
Forever Free
No paywall, no catch
Who Uses Us

Who We Serve

Built for anyone who needs to calculate change — from students to seasoned professionals.

Students & Teachers

From KS2 maths to A-level and university — our step-by-step breakdowns help users actually understand the method, not just copy the answer.

Investors & Traders

Track stock, crypto and portfolio returns over time. Our tool handles negative starting balances correctly — which most calculators don't.

Business Owners

Measure revenue growth, conversion-rate changes, churn, price elasticity and salary reviews — all in one quick, reliable tool.

Everyday Consumers

Compare rent increases, work out discount percentages, check salary offers, or verify a utility-bill rise — without any spreadsheet hassle.

Researchers & Analysts

Express experimental differences and KPI changes in a consistent, mathematically correct way — and link colleagues to the same calculation.

Journalists & Writers

Verify percentage claims in news stories, press releases and reports before publishing — accuracy matters in public communication.

Why Pick Us

What Makes Us Different

We're not the only percentage calculator online — but we are the one that gets it right and shows you why.

Mathematically Correct

Uses the standard formula with |V₁| in the denominator — handles negative starting values the way textbooks teach.

Shows Every Calculation Step

Don't just trust the output — see the difference, the ratio, and the final multiplication, all laid out clearly.

Honestly Handles Edge Cases

If V₁ = 0, we tell you the result is undefined — we don't silently return a wrong number.

No Ads In Your Face

Light, non-intrusive ad placement only. No pop-ups, no interstitials, no fake "download" buttons.

Mobile-First & Fast

Loads in under a second on 3G, works flawlessly on phones, and respects your data plan.

Built By People Who Care

We use this tool ourselves, every week. Every bug report is read. Every feature request is considered.

How We Compare

Feature Us Others
Negative value handling
Step-by-step breakdown
Zero-value explanation
Real-world clickable examples
Detailed FAQ section
Mobile-optimised design
No pop-ups or sign-up walls
Always free

Have feedback, a feature request,
or spotted a bug?

We read every message. Whether you're a daily user with an idea, a teacher who wants to use our tool in class, or a developer who found an edge case — we'd genuinely love to hear from you.

Email the Team Try the Calculator