1 April 1879 to ca April 1888
US foreign surface letter rate 5 c US Conversion rate 1 US cent = 5 goldcentimes
Swedish conversion rate 1 goldcentime = 0.72 öre for letters, 1 goldcentime=1 öre for postcards and printed matters
US marking shows the amount missing in goldcentimes.
In Sweden the indicated amount was doubled and multiplied by 0.72 for letters and 1 for postcards and printed matters. The UPU intention was
probably that 0.80 should be used for letters but Sweden normally used the commercial rate 0.72 until about 1888. The amount due was paid by affixing postage due stamps.
Letter with
4 cent. Correct rate 5 cent, Shortpaid 1 cent. US due handstamp indicates
amount missing 1x5=5 centimes. Doubled and converted to öre at the
rate 0.72; 2x5x0.72=7. 7 öre in postage dues affixed on back.