Enter the total part count printed on the runner chart along with the parts you have already attached, then add how many parts you finish in an hour and how long one sitting usually runs. The tool returns how many sittings the rest of the build will take, which is handy when you are working out how many weekend evenings a box will swallow.
Total time is the remaining parts divided by your hourly rate. The sitting count is that total time divided by the length of one sitting, rounded up. Parts per sitting is the hourly rate multiplied by the sitting length; since half a part cannot be attached, the running total is rounded up to whole parts so earlier sittings take the larger share, so a figure such as 6.5 shows as 6β7 parts, with only the leftover parts assigned to the final sitting. No official standard exists for build speed, so the rate comes from your own measurement. Current as of October 2026.
The figures are a straight extension that assumes every part takes the same time. Fiddly sections such as inner frames run slower. The order of assembly steps in the instructions, paint and decal time, and cement curing waits are not covered. Treat the figures as a reference and leave slack in your schedule.
Frequently Asked Questions
No. Which part goes on first differs with every instruction sheet and no official standard order exists. This calculator only divides a part count into working time and sittings.
Count the parts you attached in 30 minutes on your last kit and double it. Include gate clipping and sanding in the count so the figure matches real work.
The sitting count is total time divided by sitting length, rounded up, so only the leftover parts land in the final one. When the total time divides evenly by the sitting length, the last sitting is about the same as the others.