What is the percentage change from 40 to 30?

Master percentage calculations with our intuitive calculator. Whether you need to find percentages for business analysis, academic work, or everyday calculations, get precise results instantly. Features step-by-step explanations and supports decimal precision for professional-grade accuracy.

Calculate discounts instantly with our smart calculator. Whether you're shopping for deals or running a sale, quickly determine the final price after any percentage discount. Perfect for retailers, shoppers, and business owners who want accurate discount calculations in seconds.

This calculation helps consumers to determine the amount they will be able to save on a product or service, and to make informed decisions about whether or not to buy it.

When you have a fraction, it represents a part of a whole. For example, the fraction 3/4 means that you have 3 parts out of a total of 4 equal parts. To convert this fraction to a percentage, you need to express it as a proportion of 100. This as percent calculator will save your time.

BMI (Body Mass Index) is a simple and universally applied method for assessing the weight status of adults internationally.

Instantly calculate total prices including sales tax for any US state. Our calculator features up-to-date tax rates and lets you include local taxes for precise calculations. Perfect for businesses and consumers who need accurate total costs including all applicable taxes.

Simply enter your zipcode to instantly find local tax rates and calculate sales tax. Our calculator helps you determine exact tax amounts for any purchase in the US. Look up state and local tax rates by zipcode, calculate total costs including tax, and get accurate results in seconds.

Use our reverse sales tax calculator to easily find the original price from a tax-inclusive amount. Simply enter the total price with tax and the tax rate, and our calculator will instantly compute the pre-tax price and tax amount. This tool is perfect for shopping, business calculations, and everyday use, allowing you to easily convert between tax-inclusive and tax-exclusive prices. Our calculator provides detailed step-by-step explanations to help you understand the calculation process.

Calculate tips for restaurants, delivery, bars, and more. Split bills among friends and get instant results.

Calculate your potential earnings from Certificate of Deposit investments. See how different interest rates, terms, and compounding frequencies affect your returns.

Calculate your Cost Per Mille (CPM), required impressions, or advertising budget. The perfect tool for all digital marketing campaigns.

Choose your state to calculate monthly mortgage payments with accurate local property tax rates and insurance estimates.