How long a letter takes: cycle times from our own logs
A4 letters take 8.5 minutes, envelopes about a minute. These are the medians from our logs, what one machine can do with them, and which numbers we only assume.
Draft for review. Not yet approved for publication.
Before you buy a handwriting machine, you want to know how much it writes. Maker figures are given in characters per minute. For planning you need minutes per letter and per envelope, on your paper, with your text. These are ours.
What we measured
| Piece | Time | Runs |
|---|---|---|
| A4 letter, written by pen | 510 seconds (median). One run in ten took longer than 704 seconds. | 262 |
| DIN long envelope, address in pen | 63 seconds (median) | 197 |
| A5 booklet, printed | 96 seconds from one booklet to the next | 162 |
The maker states about 145 characters a minute. Early single tests of an addressed envelope took 47 to 50 seconds. The median over 197 production runs is 63 seconds, and that is the figure we plan with. A median tells you what a normal run takes. The slow tail is why a stack of 80 letters still needs a plan for the bad night.
What that means for one machine
- One hour: about 7 letters or about 57 envelopes.
- The feeder holds about 80 sheets, which is 11 hours and 20 minutes of letters. Fifty envelopes take 52 minutes. The feeder takes about 30 envelopes at a time, so that is two loads.
- Our best day so far was 63 letters, with the machine active for 14 hours.
- Writing 100 letters and 100 envelopes a day takes almost 16 hours of pure writing. One machine cannot do that in an office day.
How we fit it into a day
In our plan one person is in the room for six hours. Letters are slow and need no attention, so they run unattended from the end of the working day: 80 sheets go in, the machine writes until early morning. The next morning the person refills a few sheets, swaps to envelopes, and the machine writes them while the person packs the previous day's post. In this plan the machine writes about 16 of 24 hours.
The weak point is a jam in the night stack. It can cost up to 80 letters. We planned a reserve of about 85 minutes in the day to win some of it back, and we plan a test stack before the first full night.
What we have not measured
- Packing, stamping and filing. We assume two to three minutes per piece. This is an assumption. At two minutes, 100 pieces take 3 hours and 20 minutes. At three minutes they take 5 hours. For a single person, this decides whether the plan works.
- Pen life. We have no figure yet for how long one refill lasts. We decided to count them.
- Reply rates. We do not predict them, and the planner leaves the field for your own assumption.
Use the numbers
The planner on the home page uses these medians. Replace the cost fields with your own, and keep the packing assumption as long as you have no stopwatch figure of your own.