Bookkeeping Calculator

Pay Calculator (Gross Pay Before Tax)

Enter an hourly rate, ordinary hours and overtime to get gross pay before tax.

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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How gross pay is calculated

Gross Pay = (Rate × Ordinary Hours) + (Rate × Overtime Multiplier × Overtime Hours)

Example. $30 an hour, 38 ordinary hours and 4 hours of overtime at time and a half.

Ordinary pay = $30 × 38 = $1,140. Overtime = $30 × 1.5 × 4 = $180. Gross pay = $1,320.

Overtime rates

Time and a half is 1.5 times the ordinary rate and double time is 2 times. Which one applies, and after how many hours, depends on the award or agreement covering the job. The Fair Work Ombudsman has pay guides for each award.

What gross pay does not include

Gross pay is the amount before anything comes out. PAYG withholding tax is deducted from it to get net (take-home) pay. Superannuation is paid by the employer on top of ordinary time earnings, at 12% from 1 July 2025.

If the timesheet is in hours and minutes, convert it first with the time to decimal calculator.

Frequently asked questions

What is gross pay?

Total pay before tax and other deductions. Net pay is what is left after PAYG withholding and any other deductions are taken out.

How do I calculate time and a half?

Multiply the ordinary hourly rate by 1.5. At $30 an hour, time and a half is $45 an hour.

Does this calculator work out tax?

No. It calculates gross pay only. Tax withheld depends on the pay period and the employee’s circumstances; the ATO publishes tax tables for this.

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