Guides
Guides — guides, articles and tools from CalcaTools covering every topic in this category. Free, fast, browser-based explainers with no sign-up.
Chronological Age: What It Is & How to Calculate It
Defines chronological age and shows how to calculate years, months, and days from your birthdate to the current date.
Square Roots Made Simple: Simplify & Estimate
Learn to calculate square and cube roots on scientific calculators using √, ∛, or the general nth-root function for simplification and estimation.
How to Calculate MPG (Miles Per Gallon)
Calculate your car's MPG by dividing miles driven by gallons of gas used to measure fuel efficiency and help identify ways to save money on fuel.
How Many Hours Are in a Day, Week, Month & Year
Understand hours in common time spans: 24 hours a day, 168 hours a week, about 730 hours in an average month, and 8,760 hours in a common year.
Mulch, Gravel & Soil: How Much Do You Need?
Estimate mulch, gravel, or soil needed in cubic yards by multiplying length, width, and desired depth to plan landscaping purchases and budgets.
Ratios & Proportions: How to Solve Them
Master ratios and proportions to compare amounts and solve for unknowns; a ratio compares numbers while a proportion states two ratios are equal.
What Grade Do I Need? Final-Exam & GPA Math
Final-exam and GPA math that shows how to calculate the grade you need to hit a target GPA using a formula that weights your current grades by their value.
Percentage Difference vs Change: Formulas & Examples
Clear comparison of percentage difference versus percentage change, showing formulas and examples for comparing numbers, prices, growth, or shrinkage over time.
Days From Now & Days Ago: Counting Between Dates
Guide to counting days forward or backward from today to plan events and deadlines and calculate dates accurately.
What Time Will It Be in X Hours? Time-From-Now Guide
Time-from-now guide showing how to add hours and minutes to the current time and handle rollovers across hours and days.