Everyday Calculators
Quick answers to common daily calculations. Percentages, dates, discounts, and more. The math tools you actually use.
Simplify Your Daily Math
Some calculations come up again and again in daily life. What is 15% of this bill for a tip? How many days until that deadline? What is the sale price after this discount? How many square feet is this room? These are not complex problems, but they are tedious to do in your head and easy to get wrong. Our everyday calculators handle these common tasks instantly, so you can focus on more important things.
The beauty of these calculators is their simplicity. You do not need to remember formulas or worry about making arithmetic mistakes. Just enter your numbers and get accurate results immediately. Whether you are shopping, planning an event, measuring a space, or checking your math, these tools save time and eliminate errors.
Percentage Calculations Made Easy
Percentages appear everywhere: discounts, tips, taxes, grades, statistics, and financial returns. Yet many people find percentage calculations confusing. What is 18% of 47? If something went from 80 to 92, what percent increase is that? Our percentage calculator handles three common scenarios: finding what percent one number is of another, calculating a percentage of a number, and finding percent change between two values. No more second-guessing your mental math.
Date and Time Calculations
Date math is surprisingly tricky. How many days between two dates? What date is 90 days from now? Varying month lengths, leap years, and time zones make these calculations error-prone. Our date calculator handles it all, showing the duration between dates in days, weeks, months, and years. You can also add or subtract days from any date to find future or past dates. Perfect for project deadlines, event planning, or calculating how long until your vacation.
Shopping and Discount Math
Sales and discounts are designed to make you feel like you are getting a deal, but the actual savings can be hard to calculate quickly. Is 30% off a $149 item a better deal than $40 off? What will the final price be after the discount and tax? Our discount calculator shows the sale price, your savings in dollars, and can even factor in sales tax to show the true final cost. Shop smarter by knowing exactly what you will pay before you reach the checkout.
Area and Space Measurements
Whether you are buying carpet, planning furniture layout, or estimating paint coverage, knowing the square footage of a space is essential. Our square footage calculator handles rectangular rooms easily, but also supports circles, triangles, and L-shaped areas. You can calculate in feet, inches, or yards and convert to square meters or acres. The calculator accounts for the most common real-world measurement scenarios.
Why Simple Tools Matter
In an age of complex apps and overwhelming features, there is value in tools that do one thing well. Our everyday calculators load instantly, work on any device, and give you answers without distractions. No accounts to create, no ads covering your results, no upsells to premium versions. Just clean, fast, accurate calculators for the math you encounter every day.
All Everyday Calculators
Percentage Calculator
Percentages, changes & comparisons
Square Footage Calculator
Area for any shape in sq ft
Date Calculator
Days between dates & add/subtract
Discount Calculator
Sale price & savings instantly
Quick Math Shortcuts
Finding 10% Quickly
To find 10% of any number, just move the decimal point one place left. 10% of 85 = 8.5. Use this as a base for other percentages.
20% Tip Shortcut
Find 10% (move decimal), then double it. For a $47 bill: 10% = $4.70, doubled = $9.40 for a 20% tip.
Days in Each Month
Knuckle trick: make fists, count months on knuckles and valleys. Knuckles = 31 days, valleys = 30 (except February).
Square Feet to Yards
Divide square feet by 9 to get square yards. Useful when buying carpet or other materials sold by the square yard.
Everyday Calculator FAQs
How do I calculate percent change?
Percent change = ((New Value - Old Value) / Old Value) x 100. If a stock went from $50 to $65, the change is (65-50)/50 = 0.30, or 30% increase. Our percentage calculator handles this automatically, you just enter the two values.
How do I figure out days between two dates?
Our date calculator handles this instantly. Just enter the start and end dates, and it shows the duration in days, weeks, months, and years. It automatically accounts for varying month lengths and leap years.
How do I calculate the sale price after a discount?
Multiply the original price by (100 - discount percent) / 100. For 25% off a $80 item: $80 x 0.75 = $60. Our discount calculator does this instantly and can also add tax to show your true final cost.
What is the difference between percent of and percent change?
Percent of finds a portion: what is 20% of 150? (Answer: 30). Percent change compares two values: if something changed from 150 to 180, what percent increase is that? (Answer: 20%). Different questions, different calculations.
How do I calculate square footage of an irregular room?
Break the room into regular shapes (rectangles, triangles), calculate each area separately, then add them together. Our square footage calculator supports L-shaped areas directly, which covers the most common irregular room layouts.
Can I use these calculators on my phone?
Yes, all CalcOnce calculators are fully responsive and work great on smartphones and tablets. No app download needed. Just visit the site in your mobile browser and start calculating.
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