VAT Calculator (Any Rate)

Enter any rate to add VAT, GST or sales tax to a price, or remove it from a tax-inclusive total. Works for any country.

Bookkeeping Formula Reference

Every formula used by these calculators. They match the FNSACC323 Perform financial calculations unit.

Tax
GST: Add
Price inc GST = Price ex GST × 1.1
e.g. $100 × 1.1 = $110
GST: Remove
Price ex GST = Price inc GST ÷ 1.1
e.g. $110 ÷ 1.1 = $100
GST: Find Amount
GST = Price inc GST ÷ 11
e.g. $110 ÷ 11 = $10
Business
Markup
Selling Price = Cost + (Markup% × Cost)
e.g. Cost $50, Markup 20% → SP = $50 + ($50 × 0.20) = $60
Profit Margin
Selling Price = Cost ÷ (1 − Margin%)
e.g. Cost $50, Margin 20% → SP = $50 ÷ 0.80 = $62.50
Sales Commission
Commission = Rate% × Total Sales
e.g. $10,000 sales at 5% → Commission = $500
Simple Interest
Simple Interest
Interest = Principal × Rate × Number of Periods (T)
I = P × R × T
e.g. $300 at 2% for 1 year → I = $300 × 0.02 × 1 = $6
Total Value / Total Repayable
Total = Principal + Interest
e.g. $300 + $6 = $306
Compound Interest
Future Value (Compound)
FV = PV × (1 + i/n)^(n×t)
PV = present value, i = annual rate, n = periods/year, t = years
Present Value
PV = FV × (1 + i/n)^(−n×t)
How much to invest now to reach a future target
Loan Repayment
Repayment = P × [rp × (1 + rp)^N] ÷ [(1 + rp)^N − 1]
rp = rate per period, N = total periods
Depreciation
Straight Line: No Residual
Depreciation = Total Cost ÷ Effective Life
e.g. $11,000 ÷ 5 yrs = $2,200 per year (same each year)
Straight Line: With Residual
Depreciation = (Total Cost − Residual) ÷ Effective Life
e.g. ($11,000 − $1,000) ÷ 5 = $2,000 per year
Diminishing Value: Rate
Rate % = 200% ÷ Effective Life
e.g. 200 ÷ 12 yrs = 16.67%
Diminishing Value: Depreciation
Depreciation = Rate % × Carrying Amount
Applied to the reducing book value each year, bigger early, smaller later

GST Calculator (Australia)

GST Rate: 10%
$

Results

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Markup / Profit Margin

Markup calculates profit as a percentage of the cost price. Profit Margin calculates profit as a percentage of the selling price.

SP = Cost + (Markup% × Cost)
$
%

Results

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Sales Commission

Commission = Rate% × Total Sales
$
%
$

Results

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Break-Even Point

Units = Fixed Costs ÷ (Price − Variable Cost)

Fixed Costs stay the same no matter how much you sell (e.g. rent, insurance). Variable Cost is what it costs to make or deliver one single unit (materials, packaging, per-item shipping) — it goes up and down with sales, unlike fixed costs. Selling Price is what you charge per unit.

$
$
$

Results

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Simple Interest

I = P × R × T
$
%

Results

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Compound Interest

FV = PV × (1 + I)ᴺ
$
%
$

Results

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Present Value

PV = FV × (1 + I)⁻ᴺ
$
%

Results

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Depreciation

Depn = (Cost − Residual) ÷ Life
$
$

Results

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Time to Decimal

Decimal Hours = Hours + (Minutes ÷ 60)
hrs
min

Results

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Pay Calculator (Before Tax)

Gross Pay = (Rate × Ord. Hours) + (Rate × OT × OT Hours)
$

Results

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GST / VAT / Sales Tax Calculator

Rate: 15%
%
$

Results

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The two formulas that work for every rate

Price including tax = Price excluding tax × (1 + rate)
Price excluding tax = Price including tax ÷ (1 + rate)

Write the rate as a decimal: 20% is 0.20, 7.5% is 0.075. So at 20% you multiply or divide by 1.2, and at 7.5% by 1.075.

Example at 19%. A 300.00 net price becomes 300 × 1.19 = 357.00. The tax is 57.00.

A 357.00 total including tax is 357 ÷ 1.19 = 300.00 before tax.

Finding the tax inside a total

Tax = Total × rate ÷ (1 + rate)

At 20% that is one sixth of the total. At 10% it is one eleventh. At 15% it is three twenty-thirds.

The common mistake

Subtracting the percentage from a tax-inclusive price always takes off too much, because the percentage is being applied to a bigger number than the one the tax was originally calculated on. Divide instead.

Frequently asked questions

How do I add VAT to a price?

Multiply the price by 1 plus the VAT rate as a decimal. At 20%, multiply by 1.2.

How do I remove VAT from a price?

Divide the VAT-inclusive price by 1 plus the rate. At 20%, divide by 1.2.

Is VAT the same as GST?

They work the same way. Both are a percentage added to the price at each sale; the name depends on the country.

Tax calculators for other countries