Filament Condition Drying Time Calculator
Adjust filament drying time based on how wet it already is.
Enter exposure history, ambient humidity, and drying method to get a precise drying recommendation.
The existing drying-time guides assume you know nothing about your filament’s current state. This calculator factors in how wet the filament already is, so you’re not guessing.
How moisture absorption works. Every filament has a safe relative humidity threshold. Above that threshold, moisture enters the polymer over time. The rate depends on temperature and how far above the threshold the humidity is. Nylon can reach its saturation point in 4-6 hours at 70% RH. PLA at the same humidity takes days to reach a similar state.
Estimating current moisture level. This calculator asks how long the filament has been exposed to elevated humidity and at what level. It then estimates the moisture saturation as a fraction from 0 (bone dry) to 1.0 (fully saturated). A lightly damp spool needs the minimum drying time. A fully saturated spool needs the maximum plus extra.
Environment during drying. Standard drying environments:
- Dedicated filament dryer: precise temperature, best airflow, fastest drying
- Food dehydrator: decent but often no internal fan; add 20% time
- Kitchen oven: temperature varies widely; use an oven thermometer, add 10% and stay at lower end of temp range
- Sun/outdoor in arid climate: only practical for PLA/PETG if temperatures stay safe (below 50°C for PLA)
Spool size matters. A 1 kg spool has roughly twice the cross-sectional depth of filament compared to a 500 g spool. A 2.5 kg or 3 kg spool can need 50-80% more time than the standard 1 kg reference.
After drying. Seal immediately in an airtight container with fresh desiccant. Filament reabsorbs moisture within minutes in a humid room.