Percentage Calculator that gives you a decision, not just a number
Pick what you're actually working out — a discount, GST, a salary hike, exam marks, a price change, or reversing back to the original. Each mode shows the full breakdown, not a bare figure.
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A percentage is a question in disguise — pick the right one
Type 55000*1.18 into a search bar and you'll get 64,900 in a heartbeat. What you won't get is the part that matters: how much of that is tax, what the base was, and whether the figure on your invoice is even calculated the right way. Almost every "percentage" you deal with in real life is one of a handful of specific situations — a discount, GST, a pay revision, an exam aggregate, a price move, or working backwards to an original. Get the situation right and the arithmetic is trivial. Get it wrong and you'll under-pay a vendor, over-state a discount, or miscount your own marks. This tool is built around those situations, not a single generic box.
Discounts: the "50% + 10%" trap
Two discounts stacked are never simply added. A "50% then 10%" offer on a ₹1,000 item is not 60% off. The first cut takes ₹1,000 to ₹500; the second 10% applies to that ₹500, removing ₹50 and leaving ₹450 — an effective discount of 55%, not 60%. The Discount mode above does this in the right order and shows the effective rate so you always know the real saving.
GST: adding is easy, removing is where people slip
Adding GST is straightforward — ₹55,000 plus 18% is ₹55,000 × 1.18 = ₹64,900, of which ₹9,900 is tax. Removing GST from a tax-inclusive total is the step that trips people up. You cannot subtract 18%, because the 18% was charged on the smaller base, not on the inclusive total.
Salary hikes: what the percentage does and doesn't tell you
A hike percentage always sits on your current figure. A 30% hike on a ₹12,00,000 CTC is ₹12,00,000 × 1.30 = ₹15,60,000 — an extra ₹3,60,000 a year, roughly ₹30,000 a month on paper. The honest caveat: a CTC hike is not the same as a take-home hike. A higher gross can push you into a higher slab, and components like variable pay or employer PF inflate CTC without landing in your bank account. Use the hike % to compare offers; use the salary calculator to see what actually reaches you.
Marks: aggregate is a ratio, not an average of percentages
For an aggregate across subjects, add every mark you obtained, add every maximum, and divide — don't average the individual percentages unless every paper is out of the same total. With six papers each out of 100 it happens to be the same thing; the moment one subject is out of 50 or 150, averaging the percentages gives the wrong figure.
GPA, CGPA and percentage — three different scales
A semester GPA (sometimes SGPA) covers one term; the CGPA is the cumulative figure across every semester. The cumulative value is not a plain average of the semester GPAs unless every semester carried identical credits — it is credit-weighted. Add up each semester's GPA multiplied by its credits, then divide by the total credits.
Converting CGPA to percentage — there is no single formula
This is the step where most online calculators quietly mislead. The multiplier depends entirely on your board or university, and using the wrong one can move your percentage by more than ten points:
- CBSE: Percentage = CGPA × 9.5. It is CBSE's official conversion (and endorsed by AICTE for comparability), but CBSE itself calls the result an indicative percentage — a CGPA of 8.6 maps to 81.7%, not 86%. CBSE now reports marks directly, so this mainly matters for older CGPA marksheets.
- Many universities (e.g. Anna University): a flat CGPA × 10.
- VTU (2015/17/18 schemes): Percentage = (CGPA − 0.75) × 10 — the 0.75 is deducted because VTU's scale starts at 4.0, not 0. An 8.0 CGPA is therefore 72.5% at VTU, not 80%.
Percent vs percentage points — a genuinely costly confusion
Where each mode earns its keep
- Students: aggregate marks across subjects, and converting a single paper's score to a percentage for cut-offs.
- Shoppers: the true price after stacked festive and bank offers, and spotting inflated "discount" claims.
- Salaried professionals: comparing offers by hike %, and reversing back to a pre-raise figure.
- Small business: adding GST to a quote and stripping it out of an inclusive total before reconciliation.
Official sources & references
GST rate slabs used in the GST and Reverse modes (5%, 12%, 18%, 28%) are the notified rates under the CBIC. Verify the exact rate for a specific good or service before relying on it — rates are revised by GST Council notification.
How do I calculate the percentage of marks for 6 subjects?
Add the marks you obtained across all six subjects, add the maximum marks for all six, then divide the first total by the second and multiply by 100. For 482 out of 600 that is (482 ÷ 600) × 100 = 80.33%. Only average the six individual percentages if every subject is out of the same maximum.
How do I remove GST from an inclusive amount?
Divide the inclusive total by 1 plus the rate as a decimal. For 18%, divide by 1.18 — so ₹1,180 ÷ 1.18 = ₹1,000 base, with ₹180 GST. Subtracting 18% directly is wrong because the tax was charged on the base, not on the inclusive total.
Is a "50% + 10%" discount the same as 60% off?
No. The second discount applies to the already-reduced price. On ₹1,000, 50% off gives ₹500, then 10% off that gives ₹450 — an effective 55% discount, not 60%.
How do I calculate my salary hike percentage?
Subtract your old figure from the new one, divide by the old figure, and multiply by 100. From ₹10,00,000 to ₹12,50,000 that is (2,50,000 ÷ 10,00,000) × 100 = 25%. Remember it is a CTC percentage — take-home changes differently after tax.
What is the difference between percent and percentage points?
A move from 5% to 7% is two percentage points, but a 40% increase relative to the starting 5%. Percentage points measure the absolute gap; percent measures the change relative to the starting value.
How do I find the original price before a discount?
Divide the final price by (1 minus the discount as a decimal). A price of ₹800 after 20% off was originally ₹800 ÷ 0.80 = ₹1,000. Use the Reverse mode and choose "reduced by %".
How is CGPA calculated from semester GPAs?
CGPA is the credit-weighted average of your semester GPAs: multiply each semester's GPA by its credits, add those up, and divide by the total credits. Only take a plain average of the GPAs if every semester carried the same number of credits.
How do I convert CGPA to a percentage?
It depends on your institution. CBSE uses Percentage = CGPA × 9.5 (an indicative figure). Many universities use a flat CGPA × 10, while VTU's 2015/2017/2018 schemes use (CGPA − 0.75) × 10 — so 8.0 CGPA is 76% under CBSE, 80% under ×10, and 72.5% under VTU. Always confirm the formula on your board or university's official site.
