Failed print and waste allowance calculator
Enter what one attempt costs and how often prints fail to see what each good print really costs and what to add to your price.
Working it out…
How this is worked out
If a share of attempts fails and is thrown away, you must print more than you sell. On average you need one good print for every 1 ÷ (1 − failure rate) attempts, and the extra attempts are paid for by the good ones.
Attempts per good print = 1 ÷ (1 − failure rate)
Failed attempts per good print = attempts per good print − 1
Added to each good print = cost of one attempt × failed attempts per good print × share wasted
Cost per good print = cost of one attempt + added cost
Attempts for a batch = good prints wanted × attempts per good print
Assumptions
- The cost of an attempt, the failure rate and the share wasted are examples, not research. No reliable published failure rate for 3D print sellers could be found, so use your own record.
- Failures are spread evenly at random. A bad week of failures costs more than the average in that week.
- Your own time is not counted here. The labor calculator adds it.
Questions sellers ask
How much does a 5% failure rate add to the cost of a print?
It adds about 5.3% when each failed print is wasted in full. At a 5% failure rate each good print takes 1.05 attempts, so a print that costs $1.30 to make once costs $1.37 per good print, 7 cents more.
Why is the allowance more than the failure rate?
Because the failures are paid for by the prints that succeed. At a 10% failure rate you do not add 10%: you need 1 ÷ 0.9 = 1.11 attempts per good print, so the cost rises by 11.1%. The gap grows quickly, and a 50% failure rate doubles the cost.
How do I find my failure rate?
Count the prints that had to be thrown away or reprinted out of your last 50 or 100, including ones you stopped early. Do not guess from memory; the bad ones are the ones you remember. If you track nothing yet, start with a tally on your printer.
Should failed prints be in the price or in my costs?
Both are fine as long as they are counted once. The price calculator already adds failed prints from your failure rate, so use this tool to see how much that is, or to quote a batch, not to add it twice.