Envelope Addressing Layout Calculator
Center an address block on any envelope size, with the exact top offset for every rule line.
| Line | Top offset from envelope edge |
|---|---|
| 1 | 36.5 mm |
| 2 | 56.5 mm |
| 3 | 76.5 mm |
Not sure what line height to use? Work it out for your nib and hand with the guideline calculator. Optical center sits slightly above true center, so shifting the whole block up 3 to 5 mm from these numbers often looks better, and keep the top right corner clear for the stamp.
How it works
A centered address block on an envelope is really just one measurement: how far down from the top edge the first rule line should sit. The calculator multiplies your line count by your line height to get the total block height, then finds the gap left over above and below that block on the envelope and splits it in half. That half-gap is your top offset. From there, each following line sits one line height below the last, so the tool lists the offset for every line in the block, not just the first.
Worked example: a 3-line address on an A7 envelope (133 mm tall) with a 20 mm line height. The block itself comes out to 60 mm (3 lines × 20 mm), leaving 73 mm of empty space above and below it on the envelope. Split that in half and the first rule line lands 36.5 mm down. The second line sits one line height below that, at 56.5 mm, and the third at 76.5 mm. Rule those three lines and the whole block sits dead center on the envelope before you write a single letter.
FAQ
What line count should I use for a typical mailing address?
Most US addresses fit comfortably on 3 lines: name, street address, and city/state/zip. A longer address with an apartment or unit number, or an international address with a country line, often needs 4. Set the line count here to match whatever you're actually writing.
Where do I get the line height number?
Line height depends on your nib width and hand, the same way it does inside a full page of writing. Use the guideline calculator to work out the line height for your nib and hand, then bring that number here.
Why shift the block up from true mathematical center?
A block sitting at exact vertical center reads as slightly low to the eye, an effect called optical center. Nudging the whole block up 3 to 5 mm from the calculated offset usually looks more balanced on the envelope, especially once a stamp and postmark are added to the top right.
Does this work for square or oddly sized envelopes?
Yes. Pick "Custom size" and enter the envelope's height in millimeters (an inch is 25.4 mm, if you're converting). The centering math only depends on height, not width, so any envelope works as long as you know that one number.
For more on laying out an envelope and the lettering behind it, see how to address envelopes in calligraphy, how to lay out a balanced lettering composition, and letter and word spacing in calligraphy and lettering.