Percentage Calculators
Kitchen Worktops
Percentage Calculation & Conversions
Percentages are arguably the most common piece of math we use every day—from figuring out discounts at a store to calculating sales tax or return on investment. But the way they’re calculated changes depending on the question: Are you finding a part of a whole, or are you trying to find the whole itself?
While the concept behind a percentage is simple (a part out of 100), the calculation changes dramatically depending on whether you’re looking for the size of a part, the rate of change, or the original whole you started with.
To make sure you nail every single calculation, I’ve created a percentage calculator tool. Designed to be simple, cool, and eliminate any confusion.

Percentage Conversion Calculators
This simple dashboard is designed to solve any percentage problem you encounter, covering all the core calculations needed for finance, school, and daily life.
Find the Part of a Whole Amount
How much is a certain percentage of a total amount? (e.g., finding tax or tip)
Determine the Percentage Rate Between Two Values
What percentage does one number represent of a total number? (e.g., test scores)
Measure Increase or Decrease
Calculate the percentage growth or reduction between two values. (e.g., tracking stock price changes)
Apply a Percentage Markup or Increase
Quickly add a percentage to a base amount. (e.g., calculating sales total before discounts)
Calculate Common Proportions Instantly
Find the value of frequent percentages like 10%, 25%, or 50% of any number.
Find the Original Amount Before Tax or Discount
Work backward to find the value before a percentage was added or removed. (e.g., removing VAT from a final price)
The Three Elements of Percentage Calculations
Every percentage problem involves three main components, and your goal is always to find the missing one.
The Whole (or Base)
This is the original amount that everything is measured against. If you’re calculating a 15% tip, the Whole is the restaurant bill. If you’re tracking investment growth, the Whole is your starting balance.
The Part
This is the portion of the Whole represented by the percentage. If a shirt is £100 and you get a 20% discount, the Part is the £20 you save. Finding the Part is the most straightforward calculation:
Part = Whole × 100 Rate
The Rate
The Rate is the percentage itself, which shows the relationship between the Part and the Whole. It’s the “out of 100” metric. If you want to know what percentage your £20 profit is on a £100 investment, you’re looking for the Rate.
Ready to find the perfect stone surface for your home?
Whether you’re calculating the percentage of savings on a sale item or planning the precise worktop joints for a large kitchen island, the quality and colour of the material is paramount. At Stone Synergy, we provide premium kitchen surfaces that combine lasting beauty with exceptional performance.
Click on any of the material or colour links below to see our full ranges, detailed product specifications, and find the perfect match for your kitchen design:
Worktop Materials
- Quartz Worktops
- Granite Worktops
- Ceramic Worktops
- Porcelain Worktops
- Dekton Worktops
- Silestone Worktops
- Kitchen Worktops
Worktop Colours
- White Worktops
- Light Grey Worktops
- Grey Worktops
- Dark Grey Worktops
- Black Worktops
- Cream Worktops
- Green Worktops
- Blue Worktops
- Brown Worktops
- Matt Black Worktops
Need help deciding? Use our percentage calculator to compare the cost of different upgrades or check your budget against our fitting costs before you book your templating appointment.
Percentage Calculations & FAQs
What is a percentage, and how is it calculated? 💡
Think of a percentage as a way to say 'out of 100'. It's just a handy score!
The Calculation: You take the 'part' you're interested in, divide it by the 'whole' (the total amount), and then multiply by 100.
Example: If £20 is the part of a £100 whole, the calculation is (20 ÷ 100) × 100 = **20%**. Easy peasy!
How do I calculate the percentage saving on a sale worktop? 💰
Want to brag about your savings? Just calculate the discount amount as a fraction of the original price.
The Calculation: (Discount Amount ÷ Original Price) × 100
Example: Original Price £2,000, Sale Price £1,600. Discount is £400.
(£400 ÷ £2,000) × 100 = **20% saving**!
How do I calculate the percentage increase for a custom upgrade? ✨
Customizing is great, and it's easy to see how much more you're investing. We calculate the upgrade cost as a percentage of the base worktop price.
The Calculation: (Upgrade Cost ÷ Original Worktop Price) × 100
Example: A £300 upgrade on a £1,500 worktop is (£300 ÷ £1,500) × 100 = **20% increase**.
This calculation is vital when upgrading features! See why 'made-to-measure' is the only way to go >
What percentage of my kitchen worktop surface is non-porous? 💧
If you choose a modern engineered material like quartz, your worktop is a phenomenal **100% non-porous**!
This means it resists moisture and stains (unlike some natural stones), making it the ideal hygienic choice for busy kitchen areas.
How much money can I save with worktop offcuts? 💎
Savings can often reach **50% to 70%** off the original slab price, making them perfect for smaller projects like islands, utility rooms, or vanity tops!
The percentage discount depends on the material, size, and current demand, but the savings are always significant.
Is there a difference between standard and made-to-measure worktops? 📐
Absolutely! Standard worktops come in fixed sizes (often with a high percentage of waste). Made-to-measure means your worktop is templated and cut to perfectly fit the unique contours of your kitchen.
While the cost percentage might be higher upfront, the long-term value, precision, and perfect finish are 100% worth it.
What's the cost of getting a worktop estimate? 💸
Our estimate process is **100% free of charge**, with zero commitment from you! You can get a clear breakdown of the cost before spending a single penny.
You can't beat that percentage!