Reverse HST calculator

How to reverse HST from a total

To reverse HST, divide the total by 1 plus the HST rate and subtract: the result of the division is the price before tax and the difference is the HST.^[cra_rates] The rates are 13% in Ontario, 14% in Nova Scotia since April 1, 2025 and 15% in New Brunswick, Newfoundland and Labrador and Prince Edward Island.

• Price before tax = total ÷ (1 + rate)
• HST = total − price before tax

Worked examples. $113.00 paid in Ontario: 113 ÷ 1.13 = $100.00, so the HST is $13.00. $114.00 paid in Nova Scotia: 114 ÷ 1.14 = $100.00, HST $14.00. $1,150.00 paid in New Brunswick: $1,000.00 plus $150.00 HST.

The common mistake is taking 13% of the total. 13% of $113 is $14.69, $1.69 too much, because the total already contains the tax and 13% of it is tax on tax. The divisor method is exact: the price and tax always add back to the receipt total.

Reverse GST calculator for every province

A reverse GST calculation divides by 1.05 where only the 5% GST applies, in Alberta, Yukon, the Northwest Territories and Nunavut: $105.00 paid in Alberta is $100.00 plus $5.00 GST.^[cra_rates] Where a provincial tax is charged next to GST, divide by the combined rate and then split the tax: $112.00 paid in British Columbia is $100.00 + $5.00 GST + $7.00 PST, and $114.98 in Quebec is $100.00 + $5.00 GST + $9.98 QST, because Quebec charges 9.975% QST on the price before GST.^[rq_rules] The calculator does this split for all 13 provinces and territories.

Why the receipts are split one by one

Tax is rounded to the cent on each receipt, so the tax inside several receipts is the sum of each receipt's tax, not the tax removed from their grand total. Five $10.00 purchases in New Brunswick each hold $1.30 of HST, $6.50 in all; removing 15% from the $50.00 grand total in one step gives $6.52. The calculator shows both and flags any difference, so the figure you record matches the receipts.

Claiming the tax back: input tax credits

A business registered for GST/HST can claim the GST or HST it paid on purchases used in its commercial activities as an input tax credit on its return; tax on personal purchases cannot be claimed.^[cra_rc4022] In Quebec the QST is claimed separately from Revenu Québec as an input tax refund.^[rq_itr] Provincial sales taxes in British Columbia, Saskatchewan and Manitoba are not part of the GST/HST return, so the calculator lists them apart.

The receipt has to carry enough detail for its total: under $100, the supplier's name, the date and the total; from $100 to $499.99, also the supplier's GST/HST number and the tax charged; from $500, also your name, the payment terms and a description of what was bought.^[itc_regs] The full table of GST receipt requirements is on the GST calculator page, and the sales tax calculator for Canada shows one total in every province at once.

Common reverse tax mistakes

• Multiplying the total by the rate (113 × 13%) instead of dividing by 1.13.
• Using 15% for a Nova Scotia receipt dated after March 31, 2025; choose the "before April 1, 2025" row only for older receipts.
• Claiming PST paid in BC, Saskatchewan or Manitoba on the GST/HST return.
• Reversing tax from a total that includes zero-rated items, such as basic groceries, as if the whole receipt were taxed.
• Recording one tax figure from a grand total when the receipts were taxed and rounded one by one.

Low and modest income households get part of the sales tax back through the quarterly benefit that replaced the GST/HST credit; see the GST payment dates.