How do I work out GST backwards?

Asked by: Prof. Willy Reynolds  |  Last update: June 27, 2026
Score: 4.9/5 (25 votes)

To work out GST backwards (extract GST from a total price), divide the total GST-inclusive amount by 11 to find the GST component ( Total / 11 = GST T o t a l / 1 1 = G S T ). To find the original price excluding GST, divide the total amount by 1.1 ( Total / 1.1 = Price without GST T o t a l / 1 . 1 = P r i c e w i t h o u t G S T ).

How to find original price before GST?

For example, if the cost of a product after GST of 18% is Rs. 118, its original cost is 118 – [100/(100 + 18%)}], which equates to Rs. 100.

How to calculate sales tax backwards from total?

To calculate sales tax backwards from a total, divide the total price by (1 + the tax rate as a decimal) to get the pre-tax price, then subtract that pre-tax price from the total to find the actual tax amount. For example, for a $108 total with 8% tax, you'd calculate $108 / 1.08 = $100 (pre-tax), and then $108 - $100 = $8 (tax).
 

How do I remove 18% GST from my total amount?

Example

  1. GST Amount = ₹1,180 - (₹1,180 / (1 + (18/100))) = ₹180.
  2. Amount Excluding GST = ₹1,180 - ₹180 = ₹1,000.

How to find reverse charge in GST?

Reverse Charge Mechanism under GST is a mechanism under which the usual cycle of tax payment is reversed. Under Reverse Charge, the recipient pays to the supplier an amount exclusive of GST, the recipient then pays the GST directly to the Government. RCM is a complex concept that works in select scenarios only.

Reverse GST Calculator - How to Calculate Reverse GST?

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How to calculate GST reverse calculation?

Reverse Charge Mechanism & Calculation

  1. Formula: Base Amount = Inclusive Amount ÷ (1 + GST Rate/100)
  2. RCM: Recipient pays GST instead of supplier.
  3. Split: For intra-state: CGST + SGST | For inter-state: IGST. Our reverse GST calculator automatically handles RCM compliance calculations.

How to backwards calculate GST?

Subtracting GST:

To calculate how much GST is included in a price, just divide by 11. To calculate how much the price was before GST, just divide by 1.1. That's a lot of manual work for small-business owners to do every time they want o calculate GST—use our calculator instead.

Is a reverse GST calculator accurate?

Calculating reverse GST is important because it allows you to determine the GST-exclusive price from a GST-inclusive amount and arrive at an accurate tax amount.

How do you calculate reverse tax?

Formula Behind Financial Sales Tax Reverse Calculator

The formula is: Base Price = Total Price / (1 + (Tax Rate ÷ 100)). Total Price is the tax-inclusive amount; Tax Rate is the applicable percentage. This calculation instantly gives you both the pre-tax price and the actual tax paid.

What is the formula to take GST out of total amount?

If you only have G.S.T, which is 7%, then you would calculate the price after taxes by multiplying by 1.07. So a $200 item would cost 1.07 x $200 = $214 after G.S.T. To calculate how much G.S.T. was paid on a $214 item, simply reverse the calculation by dividing by 1.07, as $214/1.07=$200.

What is the formula for reverse GST calculation in Excel?

Using Excel to Reverse Calculate GST

Here's how to do it: Use the Formula: To reverse calculate GST, the formula is =Total Price / (1 + GST rate). For example, if the total price is ₹118 with an 18% GST, the person would type =118 / 1.18' in Excel to find the original price of ₹100.

Why use a reverse sales tax calculator?

This is especially useful when you're trying to break down a total sales price that includes the tax, but you don't have the original pre-tax amount. Why Would I Need to Calculate Reverse Sales Tax? When you only have the final total amount, including tax, and need to know the pre-tax price.

What is the formula for GST calculator?

The GST Calculator operates based on a straightforward formula: GST Amount = (Selling Price x GST Rate) / 100.

Why do we divide by 11 to get GST?

GST (Goods and Services Tax) is a 10% tax applied to most goods and services sold in Australia. Think of it as the government's slice of the pie—exactly one-eleventh (1/11th) of the total price including GST.

How to reverse calculation GST?

So, if the final price of a good is ₹1000 and GST is charged at 18%, then the base price before GST will be: ₹1000 / (1 + 0.18) = ₹1000 / 1.18 = ₹847.46 (round off) and the total GST charged is ₹152.54.

What is GST reversal with an example?

The reversal is calculated using the following formula. Example: If the buyer claimed ₹50,000 as ITC on a purchase, and the supplier failed to pay GST for 2 months out of 12 months, the ITC reversal would be calculated proportionately. As a result, the buyer must reverse ₹8,333 of the claimed ITC.

Is a reverse tax calculator free to use?

Reverse Sales Tax Calculator - Calculate Original Price Before Tax | Free Tool.

How to calculate GST backward?

You can quickly work out the cost of a product excluding GST by dividing the price of the product including GST by 11. This will give you the amount of GST applied to the product. You then multiply that figure by 10 to calculate the value of the product excluding GST.

How do you calculate $18 GST from a total?

The different slabs for GST are 5%, 12%, 18% and 28%. GST calculation can be explained by a simple illustration : If a goods or services is sold at Rs. 1,000 and the GST rate applicable is 18%, then the net price calculated will be = 1,000+ (1,000X(18/100)) = 1,000+180 = Rs. 1,180.

What is the reverse tax rule?

Under GST, the Reverse Charge Mechanism (RCM) is a system that transfers the responsibility for paying taxes from the seller to the buyer of goods or services. In most cases, the seller collects GST from the buyer and pays it to the government. However, with RCM, this process is reversed.

How to manually calculate GST?

GST is a broad-based tax of 10% on most goods, services and other items sold or consumed in Australia. To work out the cost of an item including GST, multiply the amount exclusive of GST by 1.1. To work out the GST component, divide the GST inclusive cost by 11.

What are common reverse GST calculation mistakes?

7 Common Mistakes to Avoid in Calculating GST Backwards

  • Manual Input Error. ...
  • Incorrect ITC Claims. ...
  • Not Filing Nil Returns. ...
  • GST Payment Under an Incorrect Head. ...
  • Inaccurate RCM Categorisation and Filing. ...
  • Not Reconciling GSTR-1 with GSTR-3B. ...
  • Accurate Tax Slab Calculation.