Calculation playbook
Invoice Basics Glossary
Subtotal, discount, tax, due date and invoice total terms.
Quick definitions
Use this page as a plain-language reference while using the related tools. The goal is not to replace specialist advice; it is to make common calculation terms easier to recognize.
Why the terms matter
Most mistakes happen when two similar words are treated as the same thing. A rate is not the same as a total, a monthly number is not the same as a yearly number, and an estimate is not a guarantee. The linked tools show the formula so you can see which number is being used where.
Good checking habit
Change one input at a time, recalculate, and compare the result. That makes the most sensitive part of the calculation obvious.
Related tools
Paycheck EstimatorEstimate take-home pay from gross pay, tax percentage and deductions. This is not a tax filing calculator.Overtime Pay CalculatorEstimate regular pay, overtime pay and total pay for a work week.Time Card CalculatorCalculate paid work time from a start time, end time and unpaid break.Freelance Hourly Rate CalculatorTurn annual income goals, business costs and billable time into a target hourly rate.Meeting Cost CalculatorEstimate the people-cost of a meeting from attendees, hourly rate and duration.Invoice Total CalculatorCalculate line subtotal, discount, tax and final invoice total.