Calculators you can actually trust with your numbers.

A small, carefully maintained set of calculators for pay, money, home projects and health — each one checked against official sources and explained step by step, so you understand the answer, not just see it.

Paycheck & Salary

Work out your take-home pay in any US state, see what a raise is really worth, and total up your work hours.

Personal Finance

Plan debt payoff, estimate dividend income, compare CDs and see what a mortgage recast saves you.

Business & Marketing

Price products with the right markup and margin, and plan ad spend with CPM, CPC, CTR and ROAS.

Home & DIY

Measure square footage, order the right amount of gravel, and find the pitch of any roof.

Everyday & Health

Averages, exact age, and A1C-to-glucose conversions explained in plain English.

Why use ConverterPortal?

Explained, not just computed

Every calculator comes with the formula, a worked example and answers to common questions, so you can check the result yourself.

Checked against official sources

Tax figures come from the IRS, SSA and state revenue departments; health formulas from the American Diabetes Association. Sources are listed on each page.

Kept up to date

We review pages whenever the underlying numbers change — tax brackets, wage bases, contribution limits — and show the review date on every page.