What this calculator does
A slicer works out the exact toolpath for a print, including every travel move, retraction and acceleration curve, and from that produces a fairly accurate time estimate. This calculator does the much simpler version: it takes the total filament length the slicer reports and divides it by a steady feed rate, giving a lower-bound estimate of how long the extrusion itself would take.
That simplification matters. Real prints spend meaningful time on moves where the nozzle is not extruding at all, on retraction and re-priming at every travel, and on ramping speed up and down at corners and small features. None of that is captured here, so this figure is a floor on the real print time, not a prediction of it.
The formula
Convert the feed rate from millimetres per second to metres per hour, then divide the total filament length needed by that rate to get hours.
| Term | Meaning |
|---|---|
| Filament length | The total length of filament the slicer will extrude for the whole print, as reported in its estimate summary. |
| Feed rate | How fast the printer extrudes filament during continuous printing, in millimetres per second. |
| Print time | Filament length divided by feed rate, converted to hours and minutes. |
The inputs explained
| Field | What to enter |
|---|---|
| Total filament length needed (from slicer) (m) | The total filament length the slicer reports for the complete print, usually shown in metres. |
| Filament feed rate (mm/s) | The steady extrusion feed rate for your printer and print settings, in millimetres per second. |
When to use it
Ballparking a print before slicing fully
If you already know roughly how much filament a similar model used, this gives a fast floor estimate without re-running a full slice.
Sanity-checking a slicer’s time estimate
If the slicer’s reported time is far below this floor estimate, something is off in the settings; a proper slicer estimate should always sit above the pure-extrusion figure.
Comparing feed rate settings
Trying a few feed rate values shows how much a faster print speed setting could shave off the extrusion time, before testing it for print quality.
Worked examples
Every figure in the tables below is produced by this page’s own calculator at build time, so the numbers and the tool always agree. Select any row to load that scenario.
How the time estimate changes with feed rate, at a fixed filament length
A fixed 12 m of filament, across a range of feed rates.
| Feed rate | Estimated print time |
|---|---|
| 40 mm/s | 0 h 5 min |
| 60 mm/s | 0 h 3 min |
| 80 mm/s | 0 h 2 min |
| 100 mm/s | 0 h 2 min |
| 120 mm/s | 0 h 1 min |
| 150 mm/s | 0 h 1 min |
How the time estimate changes with filament length, at a fixed feed rate
A fixed 80 mm/s feed rate, across a range of filament lengths.
| Filament length needed | Estimated print time |
|---|---|
| 5 m | 0 h 1 min |
| 10 m | 0 h 2 min |
| 20 m | 0 h 4 min |
| 40 m | 0 h 8 min |
| 60 m | 0 h 12 min |
| 100 m | 0 h 20 min |
Questions
Why is this estimate always shorter than what my slicer predicts?
Because it only counts time spent actually extruding filament at a constant speed. Slicers add travel moves between features, retraction and re-priming at each one, and acceleration and deceleration around corners, all of which take additional time this calculator ignores.
How much longer does a real print typically take?
It varies a great deal with model complexity: a simple, mostly-solid shape with few travel moves might come close to this estimate, while a highly detailed model with lots of small islands and retractions can take considerably longer than the pure extrusion time.
Where do I find the filament length figure?
Most slicers show it in the print summary alongside the estimated weight and time, usually labelled as filament length or filament used.
Does nozzle diameter or layer height affect this calculation?
Not directly here, since the calculation only uses filament length and feed rate. Those settings do affect how much filament length a given model needs in the first place, which is where their influence shows up.
To work out the weight and cost of that same filament length, use the filament weight and cost calculator. For how many layers the model will print in, see the layer count calculator.