Hi Roger

This depends where you are doing the VAT calculation and the structure of your site but in theory for global properties...

You could create a property on the very top node of you Umbraco Content tree - usually your homepage document type (perhaps on a Site Settings tab) - if you called the property 'VATRate'; you could then read this value in a template View using:

@Model.Content.GetPropertyValue("VATRate",true)

(where true, means recurse up the content tree until you find a property called 'VATRate')

or

@Umbraco.Field("VATRate", recursive: true)

will do the same.

If your calculations are in a Macro you can create a parameter on the macro called VATRateParam and pass this in from the doc type property when you render your macro like so:

@Umbraco.RenderMacro("AliasOfMacro", new {VATRateParam = "[$VATRate]"})

the $ syntax here means recurse up the tree until you find the VATRate property, you would then access this value in your macro via:

var vatRate = Model.MacroParameters.GetValue("VATRateParam")

if that helps ?

You might want to Cache the retrieved value for a period of time to prevent the work associated in accessing it from happening on each calculation; and also consider storing the rate at which VAT was calculated against each order - ie so historical orders or orders in progress don't have their VAT changed after the purchaser has committed to buy when the rate is changed globally...