Deferred Tax Calculator
for Construction

IAS 12 deferred tax for Construction

Construction entities face deferred tax complexity primarily because of timing: IFRS 15 recognises revenue over time as the performance obligation is satisfied (typically using the input or output method), while many tax jurisdictions recognise income on a different basis (completion, invoicing, or cash receipt). A construction company recognising EUR 50M of revenue on a long-term contract under the input method may have taxable income of only EUR 30M if the tax authority taxes on an invoiced basis. The EUR 20M difference creates a contract asset on the balance sheet with a tax base of zero (the revenue hasn't been taxed yet), generating a taxable temporary difference and a deferred tax liability. Multiply this across a portfolio of contracts, and the deferred tax balance swings with the stage of completion of the contract book.

IAS 12 raises four technical issues specific to construction. First, IFRS 15 contract assets and contract liabilities create temporary differences where the tax treatment of revenue and costs differs from the accounting treatment. A contract asset (unbilled revenue recognised over time) typically has a tax base lower than its carrying amount because the tax system hasn't recognised the revenue. A contract liability (advance billing) may have been taxed when invoiced but not yet recognised as IFRS revenue, creating a deductible temporary difference. Second, retention receivables (amounts withheld by the customer until defects liability periods expire) create a timing question: is the retention included in taxable income when invoiced or only when released? If taxed on invoicing, the tax base equals the carrying amount and no temporary difference arises. If taxed on receipt, the carrying amount exceeds the tax base. Third, provisions for contract losses (onerous contracts under IAS 37 or loss-making performance obligations under IFRS 15.47) create deductible temporary differences where the tax deduction follows actual expenditure. Fourth, heavy construction equipment depreciates at different rates for accounting and tax, creating the same taxable temporary differences seen in manufacturing, but construction equipment often crosses borders between projects, which may change the applicable tax jurisdiction.

Audit findings in construction deferred tax focus on the interaction between IFRS 15 and local tax. The FRC identified cases where construction entities failed to recognise deferred tax on contract assets because the preparer assumed the tax treatment matched the accounting treatment. This assumption is often wrong: the UK taxes construction contracts broadly in line with accounting (UITF 40 was superseded by IFRS 15, and HMRC generally follows the accounting), but many European jurisdictions tax construction income on completion or billing rather than on a percentage-of-completion basis. A second finding involves joint operations (common in construction), where the entity's share of contract assets and liabilities held through a joint operation under IFRS 11 generates temporary differences that the entity must include in its own deferred tax computation. Auditors sometimes miss these because the joint operation's accounts are not consolidated line by line.

For a construction entity, set up the calculator with these categories: contract assets (revenue recognised but not yet invoiced), contract liabilities (amounts invoiced but not yet recognised as revenue), retention receivables, provisions for contract losses or defects, heavy equipment (with separate accounting and tax depreciation schedules), and right-of-use assets for leased equipment. For each contract asset and liability, check the local tax treatment to determine the tax base. The calculator will compute the temporary difference and deferred tax per item.