Free online calculators for your everyday hisaab
Calculator Sathi brings 32 simple, accurate calculators in one place — age, EMI, SIP, GST, percentage, CGPA, kundli and more. Results in seconds, on any phone, without signup.
All calculators
Pick a category and open any calculator. New tools are added every week.
Finance & Investment 12 tools
EMI, SIP, GST aur savings ke saare hisaab.
Monthly SIP se kitna fund banega, expected return ke saath dekho.
Home, car ya personal loan ki monthly EMI aur total interest.
GST add ya remove karo, CGST/SGST split ke saath (5%, 18%, 40%).
15 saal ke PPF ka maturity amount aur saal-wise interest.
Fixed deposit ka maturity amount aur interest kamai.
Har mahine RD jama karne pe maturity value.
Retirement pe NPS corpus aur monthly pension ka andaza.
Mutual fund se har mahine nikaalne pe fund kitne din chalega.
Ek baar ke investment ki future value.
Alag price pe khareede shares ka average buy price.
Simple aur compound interest (byaj) dono ek jagah.
Last salary aur service ke saal se gratuity amount.
Education & Math 6 tools
Marks, CGPA, attendance aur daily math.
Percentage, increase/decrease aur marks ka percent.
Semester ke SGPA se overall CGPA.
CGPA ko percentage mein badlo (9.5 formula).
Kitne bhi numbers ka average, median aur mode.
75% attendance ke liye kitni classes chahiye ya chhod sakte ho.
Trigonometry, log, power ke saath full scientific calculator.
Date & Time 5 tools
Age, dates aur time ka exact hisaab.
Date of birth se exact age saal, mahine aur din mein.
Do logon ki umar mein exact farak.
Do dates ke beech din, ya date mein din jodo-ghatao.
Hours aur minutes jodo-ghatao, working hours nikalo.
Poore saal ka calendar, 17 gazetted holidays ke saath.
Astrology & Numerology 6 tools
Kundli, rashi, nakshatra aur numerology.
Janam kundli: Lagna, rashi, nakshatra aur grah sthiti chart ke saath.
Janam ke samay Chandrama ki rashi (Moon sign) jaano.
Apna janma nakshatra, pada aur nakshatra swami.
Kundli mein Mangal dosh hai ya nahi, Lagna aur Chandra se.
Birthday se sun sign, element aur Chinese zodiac.
Naam aur DOB se mulank, bhagyank aur name number.
Health & Fun 3 tools
BMI aur doston ke saath share karne wale fun tools.
Why people use Calculator Sathi
Calculator Sathi is a free collection of online calculators made for Indian users. Each tool answers one clear question — "What will my EMI be?", "How old am I exactly?", "What is 8.4 CGPA in percentage?" — and shows the answer instantly with a simple explanation.
Every calculator uses the same standard formulas used by banks, universities and government offices, and shows the formula on the page so you can check the math yourself.
What makes it different
- Built for India: amounts in ₹, lakh/crore format, Indian rules such as GST slabs and the 9.5 CGPA formula.
- Private: calculations run on your device. Nothing you type is stored.
- Fast on any phone: light pages that open quickly even on slow internet.
- Explained: every tool has steps, a worked example and FAQs.
How to choose the right calculator
For loans and investments
Use the EMI calculator before taking a home, car or personal loan to see your monthly payment and total interest. For investing, the SIP calculator shows how monthly investments can grow, the lumpsum calculator handles one-time investments, and the PPF, FD and RD calculators cover fixed-return savings. Businesses use the GST calculator for the new 5%, 18% and 40% slabs.
For students
The percentage calculator converts marks to percent, the CGPA to percentage tool uses the common 9.5 × CGPA formula, and the attendance calculator tells you how many classes you need to reach 75% — or how many you can skip safely.
For dates and everyday use
The age calculator gives your exact age in years, months and days — useful for government job forms and school admissions. The date and time calculators help with deadlines, notice periods and working hours, and the 2026 calendar lists all gazetted holidays.
For astrology
Make a free janam kundli from your date, time and place of birth, or find just your rashi, nakshatra or Mangal dosh. All charts use the Lahiri ayanamsa followed by most Indian astrologers.
Frequently asked questions
Are the calculators on Calculator Sathi free?
Yes. Every calculator is 100% free. You do not need to sign up, log in or install any app.
Is my data safe when I use these calculators?
Yes. All calculations run inside your own browser. The numbers and dates you enter are not sent to or saved on our server.
Do the calculators work on mobile phones?
Yes. Every tool is built mobile-first and loads fast even on slow 3G/4G connections.
How accurate are the results?
The calculators use standard formulas used by banks and institutions, so results are accurate for planning. For final loan, tax or investment decisions, please confirm with your bank or advisor, because actual rates and charges can differ.
Which calculators are most popular in India?
EMI, SIP, GST, age, percentage and CGPA to percentage calculators are among the most used tools by Indian users.
Can I suggest a new calculator?
Yes. Write to us at contact@calculatorsathi.com or use the contact page. We add new tools every week.