Pro Calculators and Guides
How to Calculate Gratuity in India: Formula and Examples
Understand the gratuity formula (last salary × 15 ÷ 26 × years of service), who is eligible and how part years are rounded.
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Pro Calculators and Guides
Specialist calculators are only useful when you understand the rules behind the numbers. These guides explain what each professional calculator does, which inputs matter, how to read the result and where the official rules come from, covering payroll and tax, immigration and visas, housing, business compliance, engineering and science. Every guide links to a free tool that runs in your browser and keeps your figures private.
318 guides
Pro Calculators and Guides
How to Calculate Hours Worked, Breaks and Pay From Start and End Times
Enter start, end and break to get hours per day, week and month, add an hourly rate to see pay, and handle shifts that cross midnight.
Pro Calculators and Guides
How to Calculate How Much Paint a Room Needs (Litres, Coats and Waste)
Work out wall area minus doors and windows, add coats and coverage per litre, and buy the right amount of paint.
Pro Calculators and Guides
How to Calculate HRA Exemption Under the Old Tax Regime (India)
Find the part of your house rent allowance that is exempt from tax, using the lowest of three amounts: HRA received, rent minus 10 percent of salary, and 50 or 40 percent of salary.
Pro Calculators and Guides
How to Calculate Permutations and Combinations (nPr, nCr and Factorials)
Learn the difference between ordered and unordered selections and compute nPr, nCr and n! with examples for lotteries, schedules and passwords.
Pro Calculators and Guides
How to Calculate PPF Maturity Amount in India (With Example)
Estimate the maturity value of a Public Provident Fund account from yearly deposit, years and interest rate, with yearly compounding.
Pro Calculators and Guides
How to Calculate Speed, Distance and Time (With Examples)
Find speed, distance or time from the other two using the simple triangle formula, with unit tips for travel and running.
Pro Calculators and Guides
How to Calculate UK Take-Home Pay With Pension and Student Loan (2026/27)
See what you really keep from a UK salary after income tax, National Insurance, pension contributions and student loan plans 1, 2, 4, 5 and postgraduate.
Pro Calculators and Guides
How to Calculate Zakat on Cash, Gold, Silver, Investments and Business Assets
Add up your zakatable wealth, subtract debts, compare with the nisab (612.36 g of silver) and find the 2.5 percent due, with a simple method.