I'm US based and do some work for company in Canada. I sent them an invoice for, say, $1,000. They paid it but the check it was for $950. When I called they told me that Canadian tax laws require them to withhold for work done in Canada, but not for work done on the project in the US. Their rules are arcane so I can't predict how much they withhold. For example, they withhold based on how long the flight is over Canadian territory, so any guess on my invoice for taxes is just a guess.
Does anyone know how to handle the withholding? I tried creating an account for it but I couldn't get my underpayment into it.
Thanks.
James