> ## Content Index
> Fetch the complete content index at: https://blog.tsd.digital/llms.txt
> Use this file to discover other available public pages before exploring further.

# 1p rounding issue on Ucommerce products/discounts
- URL: https://blog.tsd.digital/1p-rounding-issue-on-ucommerce-productsdiscounts/
- Published: 2023-03-07T12:02:15.000Z
- Updated: 2023-03-07T12:02:15.000Z
- Author: Tim Gaunt
- Tags: Ucommerce, Useful Script, #Import 2025-04-01 05:39

We've been hitting an issue over the past few years where the product's price is \`1p\` out in certain circumstances e.g. £2 off 2 £30 items -it should equal £56.00 but often results in £55.99.

The fix is surprisingly (annoyingly) simple -you need to alter the precision of the amount off award columns in Ucommerce, which are set to 2dp:

![](https://storage.ghost.io/c/64/5b/645b11c2-b436-444c-a523-58dca4ca7bd8/content/images/38805/2023-03-07_11-51-14.png)

Changing these to \`decimal(18,6)\` means Ucommerce calculates everything with sufficient precision to result in correct rounding.

You can do that like this:

```
ALTER TABLE [dbo].[uCommerce_AmountOffUnitAward] ALTER COLUMN AmountOff decimal(18,6);
ALTER TABLE [dbo].[uCommerce_AmountOffOrderLinesAward] ALTER COLUMN AmountOff decimal(18,6);
ALTER TABLE [dbo].[uCommerce_AmountOffOrderTotalAward] ALTER COLUMN AmountOff decimal(18,6);
```

Sometimes you will need to update the \`NumberOfDigitsPrecision\` setting in \`www/umbraco/Ucommerce/Configuration/Settings/Settings.config\` and change it to \`5\`.

The Math

VAT in the UK is 20% and Ucommerce requires all prices to be input excluding VAT.

£30.00 exc VAT: £25.00 (this is what’s entered in Ucommrece)£2.00 exc VAT: £1.66667 (but we can only enter £1.67 in Ucommerce due to the precision)The desired/expected total when ordering 2 is: £56.00.When calculating it out at 2dp:Unit Price: 25.00 – 1.67 = 23.33Line Total: 23.33 \* 2 = 46.66Order Total: 46.66 \* 1.2 = 55.992That then rounds down to £55.99If you calculate it to 5dp:Unit Price: 25.00 – 1.66667 = 23.33333Line Total: 23.33 \* 2 = 46.666666Order Total: 46.66 \* 1.2 = 55.99992That then rounds to £56.00