Compute your net VAT payable (or refund) before you click Submit on TaRMS. Inputs match the VAT 7 form: output VAT, input VAT, prior credit, optional apportionment.
Output = Standard supplies × 15.5% + reverse-charge VAT on imported services.
Direct input on taxable: 100%. Mixed input × (taxable / (taxable + exempt)). De minimis 90% → full claim.
Direct + apportioned mixed + reverse-charge input on imported services.
Net = Output − Input − Prior credit. Positive = pay. Negative = refund or carry-forward.
Refund > 30% of output? Recheck. Output VAT < 5% of supplies? Probably miscoded zero-rated as standard.