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What does the Home office deduction estimate calculate?
What workspace share of eligible home costs is potentially deductible? This calculator uses dedicated office area, total home area, eligible annual home costs, and business-use share of office to estimate workspace share of eligible costs immediately in your browser.
With the values currently entered, the result is $2,880.00 — potential allocated expense. It also shows allocated home share, and unallocated eligible costs.
How to use the Home office deduction estimate
- Replace the example values with your own numbers.
- Review the result and supporting figures as they update automatically.
- Check the formula and assumptions before using the estimate for a decision.
Inputs used
- Dedicated office area — entered in m²
- Total home area — entered in m²
- Eligible annual home costs
- Business-use share of office — entered in %
Home office deduction estimate formula
Office area ÷ home area × business-use share × eligible home costs
Assumptions
- Eligibility and allocation rules vary by country.
- The office area and costs must satisfy applicable local requirements.
Verify the inputs
Authoritative sources
These sources explain the definitions, factors, or rules behind this tool. Their geographic scope is shown because an official source for one country is not automatically valid somewhere else.
Sources do not endorse Calculum. Check the source date, scope, and your own documents before making a financial, tax, insurance, or reporting decision.
Practical guide
Home office deduction estimate example and edge cases
What workspace share of eligible home costs is potentially deductible? Let's use a concrete example, then look at the assumptions that can move the answer.
Example: A practical home office deduction estimate scenario
For this example, use dedicated office area of 12 m², total home area of 100 m², eligible annual home costs of 24,000, and business-use share of office of 100 %. These are starting values, so replace them with numbers that match your situation.
- Dedicated office area
- 12 m²
- Total home area
- 100 m²
- Eligible annual home costs
- 24,000
- Business-use share of office
- 100 %
Calculated result$2,880.00potential allocated expense
Start with potential allocated expense. Then check allocated home share, and unallocated eligible costs to understand what sits behind the main result.
Example results use the default display profile. The calculator above follows your selected country and units.
How to read the result
- Read the main result first. The supporting figures for allocated home share, and unallocated eligible costs explain how the estimate is built.
- The method is Office area ÷ home area × business-use share × eligible home costs. Keep the units consistent and use values from the same time period.
Edge cases worth checking
When dedicated office area is unusual
Eligibility and allocation rules vary by country. Double-check this input before relying on the result.
When business-use share of office is uncertain
The office area and costs must satisfy applicable local requirements. Run a lower and higher value to see a useful range.
What changes the result most
Dedicated office area
Measure dedicated office area with the same unit shown beside the input. Convert first if your source uses another unit.
Total home area
Measure total home area with the same unit shown beside the input. Convert first if your source uses another unit.
Eligible annual home costs
Use a current amount for eligible annual home costs. Include fees or recurring costs that belong in the same figure.
Try a different scenario
Small changes show whether the answer is stable or sensitive.
Dedicated office area: 10% lower
11 m²$2,640.00potential allocated expense
Dedicated office area: 10% higher
13 m²$3,120.00potential allocated expense
Total home area: 10% higher
110 m²$2,618.18potential allocated expense
Common mistakes
Check dedicated office area
Eligibility and allocation rules vary by country. Make sure this matches the number you enter.
Keep business-use share of office consistent
The office area and costs must satisfy applicable local requirements. Use the same units and time period throughout the calculation.
Do not rely on one home office deduction estimate scenario
Run a cautious case and an optimistic case. The range is often more useful than one exact-looking number.
Use this result well
What workspace share of eligible home costs is potentially deductible?
It is not a tax return or payroll ruling. Check the current rules for your country.