This worksheet focuses on reconciling the provisional estimate to final taxable income. For instalment dates, payment and the overall process, use the main provisional-tax guide. Main guide.
Work from taxable profit
Start with year-to-date management accounts and a realistic forecast for the remaining period. Adjust accounting profit for non-deductible expenditure, capital allowances, exempt income and available losses. Keep assumptions about unbilled work, bad debts and exceptional transactions visible.
A business with strong cash receipts can still have little taxable profit; another can owe tax while customers have not paid. Cash flow determines funding, while the tax computation determines the estimate. Reconcile the two instead of substituting one for the other.
Calculate a simple corporate example
Assume final taxable profit of €100,000 at the 2026 standard corporate rate of 15%, giving €15,000 tax. Provisional taxable profit was €60,000 and provisional tax €9,000. Because €60,000 is below €75,000, the illustrative additional charge is 10% × (€15,000 − €9,000) = €600.
The remaining ordinary tax is €6,000. The €600 is additional; separate late-payment consequences may also arise. The statutory test is “below” three quarters, so an estimate exactly at 75% is not below that boundary. This is not a recommendation to deliberately understate a forecast.
Revise using evidence
Compare the original forecast with actual trading and explain the changes. Record large contracts, asset disposals, year-end bonuses and deductible losses separately. The provisional-tax framework allows revision during the tax year; check the applicable filing instructions and payment dates before submitting it.
Ask the preparer to reconcile the revised total liability, instalments already assessed or paid and the remaining balance. Retain both submission and payment evidence. A transfer to the tax account alone may not amend the declared estimate.
Close the reconciliation
At finalisation, document the final taxable income, the last valid estimate, the 75% comparison and the tax-difference calculation. If no provisional estimate was submitted, section 26 treats the provisional amount as zero in the stated circumstances.
Use the loss schedule and capital-allowance register to support material adjustments. This makes the forecast reproducible when the final return is prepared.