Percentages, averages, fractions, ratios, and practical number tools.
Percentage Calculator
25% of 240 is 60. Formula: Result = (Percentage ÷ 100) × Number. See the substitution and rounded result.
Kinetic Energy Calculator
KE calculator for kinetic energy from mass and velocity, or the missing mass or speed, with visible ½mv² steps.
Percentage Change Calculator
80 to 100 is a 25% increase. Change % = ((New − Original) ÷ Original) × 100. Also covers decrease and unsigned difference.
Average Calculator
Add a list of numbers and divide by how many you entered to get the arithmetic mean.
Weighted Average Calculator
Combine values that should not count equally by dividing the weighted sum by the total weight.
Ratio Calculator
Simplify a ratio, scale it by a factor, or solve a missing term in a proportion a:b = c:d.
Fraction Calculator
1/2 + 1/3 = 5/6. Add, subtract, multiply, or divide two fractions, including mixed numbers, and reduce.
Decimal to Fraction Calculator
Convert a terminating decimal, or a repeating decimal, into a reduced fraction and explain the error if you stop early.
Scientific Notation Calculator
Rewrite a number as c × 10^e, expand scientific form, or add, subtract, multiply, and divide two scientific numbers.
Grades
Grade & GPA Calculators
Plan finals, combine category weights, and calculate college, high-school, and cumulative GPA.
Final Grade Calculator
Find the score you need on a final exam to reach your target course grade.
GPA Calculator
Calculate a college semester GPA on a standard unweighted 4.0 scale from letter grades and credits.
High School GPA Calculator
High school GPA calculator for unweighted 4.0 and weighted Honors, AP, and IB. A Regular A, Honors B+, AP A−, and Regular B (1 credit each) is 3.5 unweighted and 3.875 weighted.
Cumulative GPA Calculator
Merge a previous GPA with a new semester, or find the semester GPA needed to reach a target cumulative GPA.
Weighted Grade Calculator
Combine homework, quizzes, tests, and other category scores by weight to get a course percentage.
Semester Grade Calculator
Combine term and exam percentages into a semester grade, then compare two complete-semester scenarios.
Date & Time
Date & Time Calculators
Count days, compare dates, calculate work hours, and plan schedules.
Date Difference Calculator
Count the exact calendar days and elapsed weeks between two dates.
Convert Hours to Decimal Calculator
Convert hours to decimal, or change a decimal back into hours and minutes. 7:45 is 7.75; 1 hour 15 minutes is 1.25.
Hours Calculator
Find hours between two clock times, including overnight shifts, then subtract an unpaid break.
Business Days Calculator
Count weekdays between two dates, optionally excluding a versioned US federal holiday set.
Date Calculator
Add or subtract days, weeks, months, or years from a calendar date, including month-end and leap-year clamping.
Business
Business Calculators
Advertising, pricing, ROI, pay, commissions, and productivity decisions.
CPM Calculator
Calculate advertising cost per thousand impressions and compare campaign efficiency.
Markup Calculator
Calculate markup, margin, gross profit, and selling price from cost and price.
ROI Calculator
Calculate return on investment and net profit from the amount spent and the amount returned.
Pay Raise Calculator
Find the new pay after a raise, or reverse a new salary into a raise percent.
Commission Calculator
Calculate a flat-rate sales commission and optional total pay when a base salary is included.
Pro Rata Calculator
Allocate an amount across part of a period, such as a partial-month salary or a shared fee.
Productivity Calculator
Measure output per hour and, optionally, labor cost and labor cost per unit.
Everyday
Everyday Calculators
Quick tools for tips, discounts, unit prices, and daily buying decisions.
Tip Calculator
Calculate the tip, total bill, and per-person split in one step.
Discount Calculator
25% off $80 is $60. Sale price = Original × (1 − Discount % ÷ 100). Stacked rates multiply remaining price, not percents.
Unit Price Calculator
Compare two packs by price per unit so the lower unit price is obvious.
Questions
About this list
Which calculators are live?
There are 30 published tools. Finance calculators such as interest and savings are not published.
Do the calculators upload my numbers?
No. The current tools calculate in your browser and do not send inputs to KE Calculator.