Rounding on Shopify orders

Why an order can be a few cents off

Shopify holds one unit price per line, in whole cents, and multiplies it by the quantity. When the exact unit price isn't a whole cent, Shopify rounds it, so each unit can be up to half a cent off and a line can be off by up to half a cent times its quantity. That happens when:

Your prices include tax. When Include sales tax in product price and shipping rate is on in Shopify, SparkLayer sends each net price with tax added. A net price of 14.45 at 10% GST is 15.895, which Shopify can only hold as 15.90. For 30 units, Shopify comes to 477.00 with 43.36 tax, instead of 476.85 with 43.35.
A percentage discount applies. 10% off 10.97 is 9.873 a unit, so 107 units are charged 1,056.09 instead of 1,056.41.
A line is priced at more than one rate. 21 at 8.40 by the case and 2 at 11.99 each come to 200.38, but Shopify needs one unit price for the 23: 8.7122, held as 8.71, so the line comes to 200.33.
A price has more than two decimals, for example from a pricing CSV, a currency conversion or an automatic price list's percentage.

How SparkLayer handles it

The Exact net + tax totals on Shopify orders setting decides what happens:

Setting	What happens
Off (the default)	SparkLayer shows what Shopify will charge: each unit price is rounded to the nearest cent. In the tax example, the customer pays 477.00.
On	The SparkLayer cart keeps exact prices. On the Shopify order each unit price is rounded up, and a discount titled Rounding adjustment brings the order total back to the cart. In the tax example, the order shows 477.00 less a 0.15 adjustment, and the customer pays 476.85.

Our team sets it at SparkLayer Wholesale,Settings,Configurations,Pricing and cart (in your Shopify admin): contact our support team to turn it on.

With it on, two things can still be slightly off:

Shopify spreads the adjustment across the order's lines by value, so the order total is right but a single line on the Shopify order can be a few cents from its unit price × quantity.
On a store whose prices exclude tax, an order that mixes taxed and tax-free products can come out slightly high, because part of the adjustment lands on the tax-free lines. It grows with quantity: about 0.70 on an order of 1,000 units at 20%.

Avoid rounding with whole-cent prices

Choose prices that land on a whole cent

When your prices include tax, choose net prices whose price including tax is a whole cent: 10-cent steps at 10% GST, such as 14.40 or 14.50; 5-cent steps at 20% VAT; 20-cent steps at 15%. The Price Editor warns while you edit a price that won't land on a whole cent.