Calculastic
Practical calculators for pay, pricing, loans, interest, and conversions.
Use fast browser-side calculators with visible formulas, examples, assumptions, FAQs, and shareable input URLs. No sign-in and no saved account data.
Choose a calculator family
Start from the category closest to the number you already know, then move to the related calculator when the next question changes.
Pay & Income
Convert salary, hourly pay, pay periods, overtime, commission, and freelance rates with schedule-based calculators.
Open Pay & Income CalculatorsBusiness & Pricing
Calculate margin, markup, gross profit, break-even volume, unit pricing, and cost-plus pricing for practical business decisions.
Open Business & Pricing CalculatorsLoan & Interest
Estimate fixed loan payments, total interest, personal loan payments, auto loan payments, and simple interest.
Open Loan & Interest CalculatorsConversions
Convert length, weight, temperature, volume, area, time, data, speed, and kitchen units with fast calculators, visible formulas, examples, and rounding notes.
Open Conversion CalculatorsChoose by task
These entry points cover the current calculator families without forcing you through a generic directory first.
Guides and comparisons
Use these pages when the question is about definitions, tradeoffs, or choosing the right calculator.
Salary vs Hourly Pay
Salary and hourly pay are different compensation structures, not just different ways to write the same number. The right comparison depends on hours worked, overtime rules, benefits, stability, and schedule expectations.
Markup vs Margin
Markup and margin both compare price, cost, and profit, but they use different denominators. Markup is based on cost. Margin is based on selling price or revenue.
Simple Interest vs Loan Payment
Simple interest and amortized loan payments use different logic. Simple interest calculates interest on principal over time, while loan payment calculators estimate scheduled monthly payments.
How Loan Payments Work
Fixed loan payments are based on loan amount, interest rate, term, and payment schedule. The monthly payment is designed to repay both principal and interest over the loan term.
Flagship calculators
Start with a broad calculator when you are not sure which variant fits yet.
Salary to Hourly Calculator
Convert annual salary into hourly pay using hours per week and paid or worked weeks per year.
Hourly to Salary Calculator
Estimate annual gross salary from hourly pay, weekly hours, and paid weeks per year.
Profit Margin Calculator
Calculate profit and margin percentage from revenue and cost.
Markup Calculator
Calculate markup amount, markup percentage, and the related margin percentage.
Loan Payment Calculator
Estimate amortized monthly payment, total paid, and total interest.
Total Loan Interest Calculator
Estimate total interest, total paid, and monthly payment for an amortized loan.
Inches to CM Calculator
Convert inches to centimeters with the exact 2.54 cm per inch factor.
Pounds to KG Calculator
Convert pounds to kilograms using the exact 0.45359237 kg per pound factor.
Fahrenheit to Celsius Calculator
Convert Fahrenheit to Celsius with the standard subtract 32, then multiply by 5/9 formula.
Why use Calculastic?
Clear formulasEvery ranking page shows the formula, variables, assumptions, and worked examples.
No sign-inCalculators run without accounts, dashboards, or saved profiles.
Shareable inputsCalculator inputs can be carried in the URL when you need to share a scenario.
Fast static pagesPages are built for quick loading and crawlable calculator content.