The bulk of transactional mail will increase $4.50 per 1000 pieces of mail this year. There are minor differences between the Mixed AADC, AADC, and Five-digit but for practical purposes $4.50 is the number to use.
Five-digit ZIP, automated area distribution center (AADC) and mixed AADC are the three primary presort methods that the Postal Service bases their postage pricing on.
Under the five-digit tray scheme, mailers have to present a minimum of 150 mail pieces being sent to the same five-digit ZIP code as part of one bundle to qualify for the lowest level of postage.
With AADC, you have mail that isn’t presorted as finely as the five-digit ZIP mail pieces; rather, it bundles together mail that’s addressed for delivery in areas that share a common postal distribution center. AADC mail was previously grouped together based on shared three-digit ZIP codes, until the USPS ended this practice in 2016 and merged three-digit and five-digit ZIP codes under one presort scheme.
Finally, there’s mixed AADC (MAADC), which covers a broader geography of destinations – namely, any mail pieces that didn’t fit into the five-digit or AADC trays. Unlike those options, this presort method doesn’t stipulate a minimum mail piece-per-tray requirement.