Corporation Tax Calculator
Estimate your corporation tax, post-tax profit and effective tax rate based on profit, allowable deductions and tax rate.
Overview
This corporation tax calculator helps you estimate how much tax a company may owe based on profit before tax, allowable deductions, loss relief and the tax rate you enter. It can also show taxable profit, post-tax profit and the effective tax rate for planning purposes.
How it works
The calculator starts with profit before tax and subtracts allowable deductions and any loss relief to estimate taxable profit. It then applies the corporation tax rate and any additional surcharge percentage to that taxable profit. The result is the estimated corporation tax due, along with post-tax profit and an effective tax rate based on profit before tax.
How to use this calculator
- 1Enter your profit before tax.
- 2Add any allowable deductions.
- 3Enter any loss relief brought forward you want to offset.
- 4Type in the corporation tax rate for your jurisdiction.
- 5Add any extra surcharge if one applies.
- 6Review the estimated tax due, taxable profit and post-tax profit.
Example Calculation
Profit before tax
$100,000
Allowable deductions
$10,000
Corporation tax rate
21%
Loss relief brought forward
$5,000
Additional surcharge
2%
Estimated corporation tax
$19,550
With profit before tax of $100,000, deductions of $10,000, loss relief of $5,000, a 21% tax rate and a 2% surcharge, taxable profit is $85,000 and estimated total corporation tax is $19,550, leaving post-tax profit of $80,450.
Frequently asked questions
What does this corporation tax calculator estimate?
It estimates taxable profit, corporation tax due, post-tax profit and your effective tax rate based on the figures you enter.
Does this calculator use country-specific corporation tax bands?
No. It uses a flat tax rate and optional surcharge that you enter, so it is best for quick estimates rather than full tax computations.
Should I enter profit before or after tax?
Enter profit before corporation tax. The calculator then estimates the tax amount and the remaining post-tax profit.
What counts as allowable deductions?
Allowable deductions generally include qualifying business expenses and reliefs, but exact treatment depends on local tax rules. Check the rules that apply to your company.
Can I include prior year losses?
Yes. Use the loss relief field to estimate the effect of losses brought forward, if they can be used in your situation.
Why is my taxable profit shown as zero?
If your deductions and loss relief are equal to or greater than profit before tax, the calculator sets taxable profit to zero rather than a negative amount.
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Assumptions and warnings
Assumptions
- Results are estimates based on the profit, deductions, loss relief and tax rates you enter.
- The calculator applies a simple flat tax rate and any surcharge directly to taxable profit.
- Taxable profit cannot fall below zero in this calculation.
- The calculation does not include detailed jurisdiction-specific rules, thresholds, credits or group relief arrangements.
Warnings
- This calculator provides an estimate only and is not tax advice.
- Corporation tax rules, rates and reliefs vary by country and accounting period.
- Check current official rules or speak to a qualified tax professional before filing or making major decisions.