Free Online Calculator Hub
A collection of 15 free online calculators for finance (SIP, EMI, GST, compound interest), date and time, unit conversions, and everyday math. Built for Indian users with ₹ formatting and live currency rates. No signup required.
Financial Calculators
6 toolsDate & Time Calculators
4 toolsMath Calculators
3 toolsUnit Conversion Calculators
3 toolsFrequently Asked Questions
Common questions about using these calculators.
How is SIP return calculated?
SIP returns are calculated using the future value of annuity formula: FV = P × [((1 + r)^n − 1) / r] × (1 + r), where P is the monthly investment, r is the monthly rate of return (annual rate ÷ 12 ÷ 100), and n is the total number of months.
For example, a ₹10,000 monthly SIP at 12% annual return over 10 years (120 months) grows to approximately ₹23.2 lakhs — of which ₹12 lakhs is your invested amount and ₹11.2 lakhs is estimated returns.
How is EMI calculated on a loan?
EMI uses the formula: EMI = [P × r × (1 + r)^n] / [(1 + r)^n − 1], where P is principal, r is monthly interest rate, and n is tenure in months.
For a ₹10 lakh home loan at 9% for 20 years, the monthly EMI works out to roughly ₹8,997, with total interest of about ₹11.6 lakhs over the full tenure.
How do I calculate GST on a product in India?
To add GST to a base price: multiply the amount by (1 + GST rate / 100). A ₹1,000 item with 18% GST becomes ₹1,180.
To remove GST from an inclusive price: divide by (1 + GST rate / 100). A ₹1,180 inclusive price at 18% GST has a base of ₹1,000 and GST of ₹180.
Indian GST slabs are 0%, 5%, 12%, 18%, and 28%, applied based on the HSN/SAC code of the product or service.
What's the difference between simple and compound interest?
Simple interest is calculated only on the original principal: SI = P × r × t.
Compound interest is calculated on principal plus accumulated interest: A = P × (1 + r/n)^(n×t), where n is the compounding frequency per year. Compound interest grows faster, especially over long periods with frequent compounding.
Example: ₹1 lakh at 8% for 10 years gives ₹80,000 as simple interest, but ₹1.22 lakhs as compound interest (quarterly compounding).
Is this calculator free to use? Do I need to sign up?
Yes, all 15 calculators are 100% free, with no signup, no login, and no usage limits. Calculations run entirely in your browser, so nothing is stored or sent to any server — except the currency converter, which fetches live rates from a free public API.
Does the Global Time Converter handle daylight saving time?
Yes. The converter uses the browser's Intl.DateTimeFormat API with IANA timezone data, which is continuously updated by browser vendors. Cities that observe DST — like New York, London, Sydney, Chicago, and Berlin — automatically show the correct offset for the date you select.
Which is the best SIP investment period for long-term wealth?
A longer SIP horizon harnesses the power of compounding more effectively. Most financial planners recommend a minimum of 7 to 10 years for equity-oriented SIPs, with 15+ years being ideal for goals like retirement or a child's higher education. Use the SIP calculator above to model different time horizons.
How accurate are the currency conversion rates?
Rates are fetched live from exchangerate-api.com's free open endpoint, which updates every 24 hours. For indicative conversion this is accurate, but for actual transactions (remittance, forex card, international purchases) always check with your bank as the real rate includes markup, TCS, and processing fees.
About the SIP Calculator
A Systematic Investment Plan (SIP) lets you invest a fixed amount in a mutual fund at regular intervals — typically monthly. Over time, rupee-cost averaging and compounding help grow wealth steadily without timing the market.
Formula used
FV = P × [((1 + r)^n − 1) / r] × (1 + r) — where P is monthly SIP amount, r is monthly rate (annual ÷ 12), and n is total months.
Tips for using this calculator
- For equity mutual funds in India, 12% is a reasonable long-term expected return assumption.
- For debt or hybrid funds, use 6–8% instead.
- Step-up your SIP by 10% annually to accelerate wealth creation.
About the Compound Interest Calculator
Compound interest is often called the eighth wonder of the world because interest earns interest. This calculator shows how a lump-sum investment grows when interest is reinvested at a chosen frequency.
Formula used
A = P × (1 + r / n)^(n × t) — where P is principal, r is annual rate, n is compounding frequency, and t is years.
Use this for fixed deposits, PPF, EPF, bonds, or any investment where interest compounds over time.
About the EMI Calculator
EMI (Equated Monthly Installment) is the fixed amount you pay every month toward a loan, covering both principal and interest. This calculator works for home loans, car loans, personal loans, and education loans.
Formula used
EMI = [P × r × (1 + r)^n] / [(1 + r)^n − 1] — where P is principal, r is monthly interest rate, and n is tenure in months.
Typical interest rates in India
- Home loan: 8.5% – 10%
- Car loan: 9% – 12%
- Personal loan: 11% – 18%
About the GST Calculator
Goods and Services Tax (GST) is India's unified indirect tax system. This calculator lets you add GST to a base price or extract the base price from a GST-inclusive amount.
Indian GST slabs
- 0% — essential goods (fresh vegetables, milk, educational services)
- 5% — household essentials, small restaurants, transportation
- 12% — processed food, business class air travel
- 18% — most goods and services (default rate)
- 28% — luxury items, tobacco, aerated drinks
About the Discount Calculator
Quickly find the final price after a percentage discount and the exact amount you save. Useful during sales, Black Friday, festival offers, or when comparing deals across retailers.
Formula used
Final Price = Original Price × (1 − Discount / 100)
Live rates via the free exchangerate-api.com endpoint. No API key required.
About the Currency Converter
Convert between 30+ world currencies including US Dollar (USD), Euro (EUR), British Pound (GBP), Indian Rupee (INR), Japanese Yen (JPY), UAE Dirham (AED), Singapore Dollar (SGD), Australian Dollar (AUD), and more.
Rates refresh every 24 hours from a free public API. For live forex trading rates or actual remittance, check with your bank as applied rates include spreads and TCS.
About the Age Calculator
Calculate exact age in years, months, and days from any date of birth. Also shows total days lived, total months, and total weeks. Works for any date — past, present, or a future target date.
Useful for: age proof, retirement planning, pension eligibility, passport applications, or just curiosity.
About the Date Calculator
Two tools in one: find the number of days, weeks, months, or years between any two dates — or add/subtract a specific number of days from a start date to find a future or past date.
Useful for: project deadlines, pregnancy due dates, loan maturity dates, contract expiry, notice period calculations, and travel planning.
About the Time Calculator
Add or subtract two time durations expressed in hours, minutes, and seconds. Useful for timesheets, workout logs, cooking prep, video editing cuts, and shift scheduling.
About the Global Time Converter
Convert a time in one city to the equivalent time in any number of other cities worldwide. Includes 48+ major cities across India, USA, UK, Europe, Middle East, Asia Pacific, Australia, and Americas.
Common conversions covered
- IST to EST / PST / CST (India to USA)
- IST to GMT / BST (India to UK)
- IST to AEST (India to Australia)
- IST to GST (India to UAE / Dubai)
- IST to SGT (India to Singapore)
Daylight saving time (DST) is handled automatically based on the date you select, so summer and winter offsets are always correct.
About the Standard Calculator
A classic four-function calculator supporting addition, subtraction, multiplication, division, and percentage. Full keyboard support — use number keys, operators, Enter for equals, Backspace for CE, and Escape for AC.
About the Percentage Calculator
Three common percentage calculations in one tool:
- X% of Y — find a percentage of a number (e.g., 25% of 200 = 50)
- X is what % of Y — find what percentage one number is of another (e.g., 50 is 25% of 200)
- % Change — calculate the percentage increase or decrease between two values
Type in any field — the others update live.
About the Numeral System Converter
Convert numbers between decimal (base 10), binary (base 2), octal (base 8), and hexadecimal (base 16) in real-time. Essential for programmers, computer science students, and anyone working with low-level data.
Common conversions: 255 (decimal) = 11111111 (binary) = 377 (octal) = FF (hex).
About the Data Storage Converter
Convert between bytes, kilobytes (KB), megabytes (MB), gigabytes (GB), and terabytes (TB) using the binary standard (base 1024). Useful for file sizes, RAM capacity, storage drives, and network transfer estimates.
Reference: 1 KB = 1,024 bytes · 1 MB = 1,024 KB · 1 GB = 1,024 MB · 1 TB = 1,024 GB.
Type in any field to convert live.
About the Temperature Converter
Instantly convert between the three major temperature scales: Celsius (used globally), Fahrenheit (common in the US), and Kelvin (used in science).
Quick reference
- 0°C = 32°F = 273.15 K (water freezes)
- 100°C = 212°F = 373.15 K (water boils at sea level)
- 37°C = 98.6°F (normal human body temperature)
Type in any field to convert live.
About the Speed Converter
Convert between km/h, mph, m/s, and knots. Useful for driving abroad, comparing vehicle specs, aviation, sailing, and physics problems.
Reference: 100 km/h ≈ 62.14 mph ≈ 27.78 m/s ≈ 53.996 knots.
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