Because QuickBooks check envelopes are designed to improve security and work specifically with QuickBooks checks. Slightly smaller than standard #10 business envelopes, our check envelopes are 8 3⁄4” (w) x 3 9/16” (h) in order to fit more snugly and securely within the envelope, eliminating potential movement. And Like voucher checks, this means that checks printed on standard paper will fit securely in an envelope with dimensions of 3-5/8 in. x 8-11/16 in. as long as the windows are placed properly.
