Tax / VAT / GST Calculator
Add or remove VAT, GST or sales tax from any price. Works for any country and rate.
Loading calculator…
See how this fits your bigger picture → Get your free score
Like this number? Turn it into a goal and track it monthly
You might also like
📘 What is the Tax / VAT / GST Calculator?
GST calculations go in two directions that are easy to confuse: adding GST onto a base price to find the final amount, or extracting the original pre-tax price from a GST-inclusive total. This calculator handles both directions correctly, since the formula for removing GST is not simply the reverse percentage of adding it.
⚙️ How Tax / VAT is calculated
Adding GST — the straightforward direction
When you know the base price and need the final price including tax, GST is calculated as a straightforward percentage of the base price, then added to it.
Removing GST — the direction that trips people up
When you know the final, tax-inclusive price and need to find the original base price, you cannot simply subtract the tax percentage from the total — you need to divide by (1 + tax rate) first, since the percentage was originally calculated on a smaller base.
Common Indian GST slabs
India uses multiple GST slabs depending on the category of goods or services — commonly 5%, 12%, 18%, and 28% — so always confirm the applicable rate for your specific item before calculating, since picking the wrong slab is the most common source of GST calculation errors.
Removing GST from a final price
Original price = Final price × 100 ÷ (100 + GST rate)
Adding GST: Tax = Base price × rate ÷ 100
🧮 Worked examples
Example — adding 18% GST
A product with a base price of ₹1,000, GST rate 18%.
→ GST amount = ₹180, final price = ₹1,180
Example — removing 18% GST from a final price
An invoice shows a final price of ₹1,180 (GST inclusive) at the 18% rate.
→ Original base price = ₹1,000, GST portion = ₹180 — note this correctly reverses the addition example above
💡 Original insights & how to use this calculator
Why a common mistake is using the wrong direction
A frequent error is subtracting 18% directly from a GST-inclusive price (e.g. ₹1,180 × 0.82 = ₹967.60) instead of dividing by 1.18 — this gives a noticeably wrong base price. Always confirm whether your starting number already includes tax before choosing a direction.
Checking vendor invoices
If an invoice states a final price and a GST rate but not the breakdown, this calculator quickly verifies whether the implied base price and tax amount are correct, which is useful for catching billing errors.
Quoting prices to customers
Businesses can use the add-GST direction to quickly convert a base price list into customer-facing, tax-inclusive prices without manual recalculation for every item.
💡 Expert Tips
Check whether a quoted price includes or excludes tax before agreeing.
How to read your result
Adding vs. removing tax are inverse operations, but easy to mix up — 'add tax' answers 'what will this pre-tax price cost me,' while 'remove tax' answers 'what was the pre-tax price of this tax-inclusive amount I already paid.' Pick the mode that matches which number you actually have.
⚠️ Common Mistakes
✕ Assuming a quoted price already includes tax when it doesn't (or vice versa).
✓ Always confirm with the seller whether a quoted price is tax-inclusive or exclusive before calculating — this is the single most common source of GST calculation errors in practice.
✕ Using the wrong tax rate for the specific goods/service category.
✓ GST rates vary by category (essential goods, standard goods, luxury items often have different slabs) — double-check the rate that actually applies to what you're calculating.
Frequently Asked
What is VAT?▾
Value Added Tax — charged at each stage of production, ultimately paid by the consumer.
🔎 Explore related calculators
Compound Interest Calculator
Example 1 — Lump sum, no contributions
A = 1,00,000 × (1.10)^10 ≈ ₹2,59,374 — more than 2.5× growth