Build your Percentage Calculator with AI in under 5 minutes
Build a percentage calculator that answers the everyday questions in plain language — what is X% of Y, X is what percent of Y, percentage change, and increase or decrease by a percent — all in the browser.
How it works
Step 1
Describe your idea
Write a plain-text prompt describing what you want.
Step 2
AI builds it
FloopFloop generates production-ready code instantly.
Step 3
Deploy & go live
Your project is hosted on its own subdomain in minutes.
Why build with AI instead of hiring a developer?
| FloopFloop | Traditional developer | |
|---|---|---|
| Time to launch | Under 5 minutes | 2-8 weeks |
| Cost | From $0 | $5,000 - $50,000+ |
| Maintenance | Included | Ongoing retainer |
What is a percentage calculator?
A percentage calculator handles the small bits of maths that come up constantly but are just annoying enough to want a tool for: working out a tip or a discount, checking what percent of a budget you've spent, figuring a grade, or seeing how much a price changed. The four core questions cover almost everything — what is X% of a number, what percent one number is of another, the percentage change between two values, and a number increased or decreased by a percent. It's among the most-searched calculators on the web precisely because the formulas are easy to forget and easy to get backwards. A good one states each question in plain language, fills in the answer as you type, and is careful about the edge cases — dividing by zero, negative changes, values over 100% — instead of quietly showing a wrong or broken result.
Common features
- What is X% of a number
- X is what percent of Y
- Percentage change between two values (up or down)
- Increase and decrease a value by a percent
- Plain-language, fill-in-the-blank layout
- Live results as you type
- Up/down direction shown for changes
- Safe handling of divide-by-zero (shows a dash)
- Copy any result; everything client-side
- Light and dark themes; inputs remembered
Real-world examples
A discount
Someone works out 25% off a $80 item by reading the 'decreased by' result — $60 — without reaching for a separate calculator.
A grade
A student types 'what percent is 46 of 60' and gets 76.6667% instantly.
A price change
A shopper checks the percentage change from $50 to $75 and sees a green ↑ 50% — and from $100 to $80, a red ↓ 20%.
Why FloopFloop fits percentage calculator projects
A percentage calculator is a tiny tool you want instant, ad-free, and yours. FloopFloop ships the calculator you want — the exact modes you use, VAT or sales-tax presets, your own wording — on your own domain, with every calculation running in the browser. The friendly 'sentence' cards that ship by default state each question in plain English with the answer right there, and the whole thing is one prompt away from being whatever fits your workflow.
Try these prompts
Copy any prompt below and paste it into FloopFloop to get started.
Build a percentage calculator with plain-language cards. Card 1: 'What is P% of N?' Card 2: 'X is what percent of Y?' Card 3: 'Percentage change from A to B?' with an up/down arrow and colour. Card 4: a value increased and decreased by P%, showing both. Inline number inputs inside the sentences, results that update live, and a copy button on each. Guard against dividing by zero (show a dash). Keep it deterministic so the first render is hydration-safe, and remember every input in localStorage. 100% client-side.
Create a percentage calculator like the popular ones: type two numbers and get the percent. Cover 'what is X% of Y', 'X is what % of Y', and percentage increase/decrease. Keep it in the browser.
Build a friendly percent calculator for everyday maths — discounts, tips, grade percentages, percentage change — with a clean card layout and a dark theme.
Build a tool to work out percentage change between two numbers, showing whether it went up or down and by how much.
Frequently asked questions
What can it calculate?
How do I work out a percentage of a number?
What's the difference between percentage change and percentage points?
What happens if I divide by zero?
Is anything sent to a server?
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Ready to build?
Start building your project now — no coding required.
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