Home office

Work out the home office claim and keep one journal per year up to date.

Financial year

Business use

30.43%

Floor area · 42 m² of 138 m² used for business

Floor area Time based

Office area (m²)

Garage used (m²)

Storage (m²)

Total home + garage (m²)

Business area 42 m² ÷ 138 m²

= 30.43%

Sole trader · Registered for GST GST is claimed at the business-use %. Rent and mortgage interest carry no GST.

Category	Account	Annual amount	Bus use %	Home office	GST	Net (deduction)
Mortgage interest	462 Interest	18,400.00	30.43	5,599.12	No GST	5,599.12
Council rates	445 Rates	3,250.00	30.43	988.98	128.99	859.99
Power	448 Light, power, heating	2,880.00	30.43	876.38	114.31	762.07
Gas	448 Light, power, heating	1,140.00	30.43	346.90	45.25	301.65
House insurance	433 Insurance	2,150.00	30.43	654.25	85.34	568.91
Internet	489 Telephone & internet	1,320.00	60.00	792.00	103.30	688.70
Mobile	489 Telephone & internet	960.00	90.00	864.00	112.70	751.30
Repairs & maintenance	473 Repairs & maintenance	780.00	30.43	237.35	30.96	206.39
Total		30,880.00		10,358.98	620.85	9,738.13

Amber % = overridden from the derived rate.

Journal posted One journal for FY2026, dated 31 Mar 2026 · updated when figures change.

Dr expenses $9,738.13 · Dr GST $620.85 · Cr Owner's funds $10,358.98 — GST claimed in your Jan–Mar 2026 return.