Free online calculators for students, employees and everyday use
Work out your SGPA, attendance, exam score, DA, expected 8th Pay Commission salary, age or work experience in seconds. Every calculator on CalcShala shows the formula behind the answer and a worked example, so you can check the result yourself instead of just trusting a number.
Last reviewed: October 2026
Education & Exam Calculators
Tools for college students and exam aspirants: grades, attendance, admission scores and marking schemes. Enter your numbers and get an instant result without manual calculation.
SGPA & CGPA Calculator
Find your semester grade point average from subject credits and grade points, and combine semesters into a CGPA.
Free • No signup
Open Tool →SRM CGPA Calculator
Calculate your SRM cumulative GPA by entering grades and credits for each subject.
Free • No signup
Open Tool →Attendance Calculator
Check your attendance percentage and see how many classes you can miss or must attend.
Free • No signup
Open Tool →Negative Marking Calculator
Estimate your exam score from correct answers, wrong answers and the negative marking scheme.
Free • No signup
Open Tool →NUST Aggregate Calculator
Estimate your NUST admission aggregate from your test and academic marks.
Free • No signup
Open Tool →Salary & Government Employee Calculators
Useful for central and state government employees who want to understand allowances and plan for pay revisions.
DA Calculator
Work out your Dearness Allowance from basic pay and the current DA percentage.
Free • No signup
Open Tool →8th Pay Commission Salary Calculator
Estimate your expected salary after the 8th Pay Commission from basic pay, pay level and fitment factor.
Free • No signup
Open Tool →Money Calculators
Quick helpers for everyday cash handling.
Cash Denomination Calculator
Split any amount into the fewest notes and coins, or total your cash by denomination.
Free • No signup
Open Tool →Career & Date Calculators
Helpful when filling job applications, resumes and service records, or when you need an exact gap between two dates.
Experience Calculator
Get your total work experience in years, months and days between any two dates.
Free • No signup
Open Tool →Age Calculator (Between Two Dates)
Find the exact gap between two dates in years, months and days, for age on a given date or any date range.
Free • No signup
Open Tool →All calculators at a glance
A quick comparison to help you pick the right tool.
| Calculator | You enter | You get | Best for |
|---|---|---|---|
| SGPA & CGPA | Credits and grade of each subject | Semester and cumulative GPA | College students |
| SRM CGPA | Grades and credits across semesters | Cumulative GPA | SRM students |
| Attendance | Classes attended and total classes | Percentage, classes to attend or skip | School and college students |
| Negative Marking | Correct, wrong, marking scheme | Expected exam score | Competitive exam aspirants |
| NUST Aggregate | Test and academic marks | Admission aggregate | NUST applicants |
| DA | Basic pay and DA % | Dearness Allowance amount | Government employees |
| 8th Pay Commission | Basic pay, pay level, fitment factor | Estimated revised salary | Government employees |
| Cash Denomination | An amount or note counts | Notes and coins breakdown | Shops, banks, households |
| Experience | Start and end date | Years, months, days | Job applicants |
| Age (Between Two Dates) | Two dates | Years, months, days between them | Forms, eligibility checks |
How our calculators work: formulas, steps and examples
Each calculator is built on a standard formula. Below you will find the formula, how to work it out by hand, and a worked example. Universities, employers and exam boards can have their own rules, so use these as the standard method and check your official guidelines for the final figure.
SGPA and CGPA
SGPA = Σ (Credit × Grade Point) ÷ Σ Credits
SGPA is the credit-weighted average of grade points in one semester. CGPA uses the same idea across all semesters together, so subjects with more credits count for more.
How to calculate
- Multiply each subject's credits by its grade point.
- Add up all these products.
- Divide by the total credits of the semester.
Good to know: A common 10-point scale is O = 10, A+ = 9, A = 8, B+ = 7, B = 6, C = 5. Your university may use different points or exclude audit subjects, so check your grade sheet.
SGPA example (one semester)
| Subject | Credits | Grade | Grade point | Credits × GP |
|---|---|---|---|---|
| Mathematics | 4 | A+ | 9 | 36 |
| Physics | 3 | A | 8 | 24 |
| Programming | 3 | B+ | 7 | 21 |
| Total | 10 | 81 |
SGPA = 81 ÷ 10 = 8.1
CGPA example (two semesters)
| Semester | Credits | SGPA | Credits × SGPA |
|---|---|---|---|
| Semester 1 | 22 | 8.2 | 180.4 |
| Semester 2 | 24 | 7.9 | 189.6 |
| Total | 46 | 370.0 |
CGPA = 370.0 ÷ 46 = 8.04 (rounded to two decimals). A plain average of 8.2 and 7.9 would give 8.05, so the credit weighting matters.
Attendance percentage
Attendance % = (Classes attended ÷ Total classes) × 100
Most colleges ask for a minimum attendance, and 75% is very common. These shortcuts work for a 75% requirement:
How to calculate
- Divide classes attended by total classes and multiply by 100.
- Classes you must attend to reach 75% = 3 × Total − 4 × Attended.
- Classes you can still miss = (4 × Attended − 3 × Total) ÷ 3, rounded down.
Good to know: Medical and duty leave are treated differently by different institutions. Check your rulebook before relying on any figure.
Where do you stand against 75%?
| Attended / Total | Current % | What it means |
|---|---|---|
| 30 / 50 | 60.00% | Attend the next 30 classes without a miss |
| 40 / 60 | 66.67% | Attend the next 20 classes without a miss |
| 45 / 60 | 75.00% | Exactly on the line, you cannot miss any |
| 45 / 55 | 81.82% | You can miss up to 5 more classes |
Negative marking
Score = (Correct × Marks per question) − (Wrong × Negative marks)
Negative marks are deducted only for wrong answers. Questions you leave unattempted score zero.
How to calculate
- Multiply correct answers by the marks for each question.
- Multiply wrong answers by the negative marks per wrong answer.
- Subtract the second figure from the first.
Good to know: With 4 options and ⅓ negative marking, a blind guess is worth exactly zero on average. If you can eliminate even one option, guessing starts to pay off.
Same answers, different schemes
| Scheme | Marks lost | Final score |
|---|---|---|
| ¼ per wrong answer | 5.00 | 65.00 |
| ⅓ per wrong answer | 6.67 | 63.33 |
| ½ per wrong answer | 10.00 | 60.00 |
100 questions, 1 mark each: 70 correct, 20 wrong, 10 unattempted.
Expected value of a blind guess (4 options)
| Scheme | Expected marks per guess |
|---|---|
| ¼ negative | +0.0625 |
| ⅓ negative | 0.0000 |
| ½ negative | −0.1250 |
Dearness Allowance (DA)
DA = Basic Pay × DA % ÷ 100
DA is an allowance that helps government employees offset rising living costs. It is calculated as a percentage of basic pay.
How to calculate
- Take your current basic pay.
- Multiply by the current DA percentage and divide by 100.
- Add the result to basic pay to see pay plus DA.
Good to know: DA is usually revised twice a year, with effect from January and July. Announcements often come later and may include arrears. Always use the latest rate. The table uses an illustrative 50%.
DA at an illustrative 50%
| Basic pay (₹) | DA at 50% (₹) | Basic + DA (₹) |
|---|---|---|
| 30,000 | 15,000 | 45,000 |
| 50,000 | 25,000 | 75,000 |
| 80,000 | 40,000 | 1,20,000 |
8th Pay Commission salary estimate
New Basic Pay ≈ Current Basic Pay × Fitment Factor
A pay commission revises salaries by applying a fitment factor to existing basic pay. The calculator lets you try different factors to see the range of outcomes.
How to calculate
- Note your current basic pay.
- Multiply it by the fitment factor you want to test.
- Compare the new figure with your current pay to see the increase.
Good to know: The final factor and pay matrix will be decided and notified by the government. These figures only show how the factor changes the result. They are not predictions.
Effect of different fitment factors (illustration)
| Current basic (₹) | Factor | New basic (₹) | Increase (₹) |
|---|---|---|---|
| 50,000 | 1.80 | 90,000 | 40,000 |
| 50,000 | 2.00 | 1,00,000 | 50,000 |
| 50,000 | 2.50 | 1,25,000 | 75,000 |
Work experience
Experience = End date − Start date (in years, months and days)
Useful for job applications, resumes and service records where you need exact experience instead of an approximate number.
How to calculate
- Count full years from the start date.
- From there, count full months.
- The remaining days make up the last part.
Good to know: Some employers also count the last working day. If yours does, add one day to the result.
Experience examples
| Start date | End date | Experience |
|---|---|---|
| 01 Apr 2021 | 01 Apr 2026 | 5 years, 0 months, 0 days |
| 15 Jan 2022 | 20 Mar 2026 | 4 years, 2 months, 5 days |
| 10 Aug 2018 | 05 Oct 2026 | 8 years, 1 month, 25 days |
Age between two dates
Age = Later date − Earlier date (in years, months and days)
The method is the same as for work experience: whole years first, then whole months, then the leftover days. Use it for your age on a particular date, such as the cut-off date in a form or exam notification.
How to calculate
- Add whole years to the earlier date until adding one more would pass the later date.
- Add whole months in the same way.
- Count the remaining days.
Good to know: Eligibility rules often say "age as on" a fixed date. Use that date as the later date, not today's date.
Age examples
| Earlier date | Later date | Age / gap |
|---|---|---|
| 12 Mar 2000 | 31 Oct 2026 | 26 years, 7 months, 19 days |
| 05 Jun 1995 | 31 Oct 2026 | 31 years, 4 months, 26 days |
| 20 Dec 2010 | 15 Aug 2026 | 15 years, 7 months, 26 days |
Cash denominations
Start with the largest note, then move down to smaller ones
Using the largest notes first gives the fewest notes for any amount. This is handy for cash counting, bank deposits and payouts.
How to calculate
- Divide the amount by the largest note and keep the whole number.
- Take the remainder and repeat with the next smaller note.
- Continue until the remainder is zero.
Breaking down ₹3,780
| Note | Count | Amount (₹) |
|---|---|---|
| ₹500 | 7 | 3,500 |
| ₹200 | 1 | 200 |
| ₹50 | 1 | 50 |
| ₹20 | 1 | 20 |
| ₹10 | 1 | 10 |
| Total | 11 notes | 3,780 |
Common calculation mistakes to avoid
Most wrong answers come from using the right formula on the wrong inputs. These are the slips we see most often with these calculations.
Averaging SGPAs without credits
If semesters carry different credits, a plain average of SGPAs gives a slightly wrong CGPA. Weight each SGPA by that semester's credits.
Ignoring how leave is counted
Colleges treat medical and duty leave differently. Check whether such classes are removed from the total before you trust any attendance figure.
Guessing blindly under ⅓ marking
With four options, a blind guess earns nothing on average. The gain comes only when you can rule out at least one option.
Using an old DA rate
DA changes with each revision. Using last year's percentage gives an outdated allowance, so confirm the latest rate from your office order.
Treating a pay estimate as final
A fitment factor you try out is only a scenario. The notified factor and pay matrix are what decide the real figure.
Using today's date for eligibility
Forms usually ask for age or experience "as on" a fixed cut-off date. Enter that date as the end date, not today's date.
How we keep CalcShala accurate
- Formula and example on the page. Every result can be checked by hand using the steps and tables above.
- Rules that differ are flagged. Grade scales, attendance limits and rounding vary by institution, so we say so instead of assuming one rule fits everyone.
- Estimates are labelled as estimates. Pay commission figures are scenarios, not official calculations, and are never presented as final.
- Mistakes get fixed. If you spot an error, tell us through the Contact Us page and we will review and correct it.
Frequently asked questions
Quick answers about our calculators, the formulas behind them and how to use the results.
