Free Online Calculators

Calculators that explain the answer

CalculatorWorld is a free library of 41 online calculators and converters for everyday decisions in India: planning a home loan, comparing the old and new tax regimes, checking an exam age limit, working out a CGPA, or converting a recipe from cups to grams. You get the answer instantly, and the page also shows how that answer was reached.

Each calculator page includes:

• The formula in plain notation, so you can check the result or do it by hand in an exam.
• Worked examples with realistic Indian numbers: rupees, lakhs, FY 2026-27 tax slabs, the 75% attendance rule, RBI loan-to-value limits.
• Reference tables: EMI by tenure, healthy weight by height, cm-to-feet charts, margin-to-markup conversions and more.
• Honest limitations. We say what a calculator doesn’t cover, such as surcharge marginal relief, BMI for athletes or bank forex markups, so you know when to ask a professional.

Up to date with Indian rules

Rules change, and a calculator built on last year’s rules gives wrong answers. Our Income Tax Calculator uses the FY 2026-27 slabs (tax-free income up to ₹12 lakh under the new regime, and up to ₹12.75 lakh for salaried people). The GST Calculator reflects the 5% / 18% / 40% structure in force since 22 September 2025. The Salary Calculator works through PF caps, gratuity and professional tax. When a Budget or notification changes the rules, we update the tools and record the date on each page.

Private by design

Every calculation happens in your own browser. Your date of birth, salary, loan amount or health details are not sent to our server or stored. The pages are lightweight and fast on mobile data, and the calculators keep working even if your connection drops after the page has loaded.

Who uses CalculatorWorld?

• Students checking attendance, marks percentage, CGPA and practising percentage, fraction and speed problems for competitive exams.
• Salaried professionals comparing tax regimes, decoding CTC offers and planning SIPs and loan prepayments.
• Small businesses and freelancers adding or removing GST, pricing for margin and setting payment deadlines in business days.
• Families tracking a child’s age in months, planning a home purchase, or converting heights and weights.
• Developers formatting JSON, decoding Base64 and converting Unix timestamps without pasting data into unknown servers.

How we build and check each tool

Each calculator is built from a published formula or official rule, tested against hand-worked examples and independent references, and reviewed again whenever the underlying rules change. Read more in our editorial policy. Found something that looks wrong? Tell us on the contact page. We fix confirmed errors quickly and note the update on the page.

Frequently asked questions