To add VAT: multiply the base price by 1.13. For example, NPR 10,000 × 1.13 = NPR 11,300 (VAT = NPR 1,300). To remove VAT from an inclusive price: divide by 1.13. NPR 11,300 ÷ 1.13 = NPR 10,000 base, NPR 1,300 VAT. This calculator does both — just pick the mode.