Free Percentage Calculator
A free percentage calculator finds X% of a number, adds or subtracts a percentage from an amount, and extracts tax from tax-inclusive totals using reverse tax calculation. Enter values and get instant results — no signup, runs in your browser.
Solve everyday percentage problems: what is 15% of 200, add 18% to a price, subtract a discount, or split tax out of a tax-inclusive total. The reverse tax method is widely used for GST invoices — enter an 18% rate on ₹5,90,000 and get ₹90,000 tax with ₹5,00,000 base. Six modes, free, no signup, instant local results.
What is X% of Y?
Example: 15% of 200 → 30
Runs 100% in your browser. Your data never leaves your device.
Standard percentage formulas in JavaScript — simple arithmetic with no server round-trips.
How to Use Percentage Calculator
- Choose a calculation mode — percent of, add/subtract percent, or tax from inclusive total
- Enter the percentage and amount in the input fields
- The result updates instantly as you type
- Use tax from inclusive total when the price already includes tax — the standard GST invoice method
When Would You Use This?
Shoppers comparing sale tags use percent change mode to see if '30% off then extra 20% off' beats a flat discount — the math is easy to get wrong mentally.
Retailers marking up wholesale prices add a margin percent to cost in one step before rounding for display.
Accountants and business owners in India use reverse tax calculation daily for GST: when an invoice shows ₹5,90,000 inclusive of 18% GST, the tax portion is not 18% of 5,90,000 — it is 5,90,000 × 18 ÷ 118 = ₹90,000, leaving ₹5,00,000 as the taxable value. That split is required for GSTR filings and input tax credit reconciliation. The tax from inclusive total mode applies this formula automatically so you do not have to remember ÷1.18 or build a spreadsheet for every line item.
Frequently Asked Questions
- Is this percentage calculator free to use?
- Yes, completely free. No signup, no login, no payment ever.
- Do I need to create an account?
- No account needed. Open the tool and start using it immediately.
- Is my data safe?
- Everything runs in your browser. Nothing is uploaded to our servers. We cannot see your data.
- How do I calculate a percentage increase?
- Use percent change mode. Enter the original value and the new value — the tool shows the percentage increase or decrease.
- How do I calculate GST from a tax-inclusive amount?
- Use the Tax from inclusive total mode. Enter the GST rate (e.g. 18 for 18% CGST+SGST) and the inclusive total (e.g. 590000). The tool applies reverse tax calculation: tax = total × rate ÷ (100 + rate). For 18% on ₹5,90,000, GST is ₹90,000 and the base amount is ₹5,00,000.
- What is the reverse tax calculation formula?
- When tax is already included in the total, tax amount = inclusive total × (tax rate ÷ (100 + tax rate)). Base amount = inclusive total × (100 ÷ (100 + tax rate)). This is the standard method for splitting GST, VAT, or sales tax out of a gross price — not simply multiplying the total by the rate.