SwiftFree Online Calculators
with Formula Guides
Check a semester’s GPA, count working days, or coordinate across time zones. Simple calculators, with the reasoning right beside them.
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Popular grade, math & date calculators
GPA calculator
Combine grades and credits, with an optional previous GPA.
Open calculator GPA & Grade CalculatorsFinal grade calculator
Find the final-exam score needed for your course target.
Open calculator Percentage CalculatorsPercentage calculator
Find a percentage, a share, or a percentage change.
Open calculator Date & Time CalculatorsWork days calculator
Count work days with your own weekends and holidays.
Open calculator Date & Time CalculatorsAge calculator
Find completed years and elapsed days on a chosen date.
Open calculator Date & Time CalculatorsTime zone converter
Convert a dated time between named time zones.
Open calculatorCalculator formulas & step-by-step guides
Read the assumptions, follow an example, and check that the model fits your situation.
Our calculation methods →Will a 120-point project drop you a letter grade? Before-and-after math
Add one 120-point project to both sides of the fraction and see exactly when an assignment moves your letter — and when it cannot.
Read the guide ↗What letter grade is 1,073.5 out of 1,240 points? (and the 5.3 points to the next one)
Convert points earned and points possible into a percentage and letter grade — and find the exact points needed for the next letter up.
Read the guide ↗