What date do I use for converting an invoice from Euro to USD?

We order regularly with companies in Europe, often in the $100K+ range per order. With the Euro going up so much between the date we quoted our customers and sent a purchase order (Aug 1) and the date we received the goods (Nov 15), our profit is almost wiped out.

Example: We place an order at EU€100,000 on August 1, quoting our customer based on a cost of USD$136,800. The vendor ships the goods on Oct. 1, when the order is now costing us USD$142,300. We receive the goods on Nov 15 with the invoice for EU€100,000, but now our cost is USD$146,400. (We pay in USD$)

What is the generally accepted date to use for determining the conversion from Euros to USD$?

Options:

Date order was placed with supplier?
Date order was confirmed by supplier?
Date order shipped by supplier?
Date order received by us?
Date on the invoice we received?


Thanks for your help.

We order regularly with companies in Europe, often in the $100K+ range per order. With the Euro going up so much between the date we quoted our customers and sent a purchase order (Aug 1) and the date we received the goods (Nov 15), our profit is almost wiped out.

My question is what is the generally accepted date to use for determining the conversion from Euros to USD$?

Options:

Date order was placed with supplier?
Date order was confirmed by supplier?
Date order shipped by supplier?
Date order received by us?
Date on the invoice we received?


Thanks for your help.
The date the costumer order and agree to pay an amount for the products or services you provide

I appreciate the response, Student 101, but I'm not sure that gets at the heart of my question. I need to be able to convince the vendor I'm buying from that I should pay them in USD based on the Euro exchange rate at the time I placed my order with them.

Since they bill me in Euros, but I pay in USD, I need some back-up to show why I am paying them USD$136,000 vs. USD$146,000 as their invoice would require.

I appreciate the response, Student 101, but I'm not sure that gets at the heart of my question. I need to be able to convince the vendor I'm buying from that I should pay them in USD based on the Euro exchange rate at the time I placed my order with them.

Since they bill me in Euros, but I pay in USD, I need some back-up to show why I am paying them USD$136,000 vs. USD$146,000 as their invoice would require.


I'll jump in here with my thoughts.
No vendor that bills in Euros is going to buy your argument, and if you send them $136,000 they will probably reinvoice you some difference.
They want to be paid in Euros and frankly, don't care what the FX rates have done.
You basically have three choices, 1. find an American supplier or a supplier who will bill in USD, 2. pay the vendor his Euros and in the future, make sure that you charge enough to cover the additional costs that the Euro might cost you, or 3. buy Euros in advance on the date that you put your order in.

Regards, herman