Finance Tools
Finance Tools — guides, articles and tools from CalcaTools covering every topic in this category. Free, fast, browser-based explainers with no sign-up.
The Psychology and Math of Budgeting: How the 50/30/20 Rule Transforms Personal Finance
Analysis of the 50/30/20 budgeting rule and the math behind it to transform personal finances by allocating needs, wants, and savings in a clear framework.
$20 an Hour Is How Much a Year? (Convert Any Hourly Wage)
Convert hourly pay to annual salary using rate×hours×52 or rate×2,080; includes a conversion table and gross vs take-home notes.
Sales Tax 101: How to Calculate, Reverse-Calculate, and A…
Sales Tax 101 covers how sales tax works for retail pricing, tax filing, or budgeting groceries, including how to calculate and reverse-calculate tax.
Compound vs. Simple Interest: The Math That Quietly Doubl…
Compound vs simple interest: with the same rate and principal the outcomes differ; what compound interest does to money and when simple interest still wins.
The Mortgage Payment Formula Explained: How Lenders Reall…
Mortgage payment formula explained: the PMT formula, the four numbers that move your monthly payment most, and how to model it in two minutes.