Storage losses build up gradually over time from moisture, pests, and temperature conditions specific to how and where a commodity is kept — distinct from the one-time losses that happen during harvest or transport. This calculator estimates the percentage and value of product lost specifically during the storage period based on storage type, duration, moisture level, and pest control measures.
Loss rate increases with storage duration (longer storage means more cumulative exposure to spoilage risk), moisture content above the safe threshold for the commodity, inadequate storage type for the product, and absence of pest control measures. These factors compound — wet grain stored long-term without pest control faces substantially higher risk than any single factor alone would suggest.
| Storage Condition | Typical Monthly Loss |
|---|---|
| Good (dry, sealed, pest-controlled) | 0.3-0.8% |
| Fair (basic storage, some pest risk) | 1-2% |
| Poor (open storage, high moisture, no pest control) | 3-6%+ |
For 8,000 kg of maize stored for 6 months at 14% moisture (slightly above the 13% safe threshold) in a basic warehouse with occasional pest control: this falls in the "fair" range at roughly 1.5%/month, compounding to approximately 8-9% total loss over the 6-month period — around 640-720 kg. At PKR 55/kg, that represents a loss value of PKR 35,000-40,000, which better moisture control and consistent pest management could have substantially reduced.
Even 1-2 percentage points above the safe moisture threshold can double or triple mold and insect risk during extended storage, since most storage pests and fungi thrive specifically in that slightly-elevated moisture range rather than at very low or very high extremes.
Generally yes for the same conditions — cumulative exposure to pests, temperature fluctuation, and any moisture migration within the storage mass increases with time, which is why this calculator scales expected loss with storage duration rather than treating it as a fixed one-time percentage.
Proper sealing to exclude insects and rodents, combined with either fumigation or approved storage protectants, are the most effective measures — physical exclusion alone (a well-sealed structure) can cut pest-related losses substantially even without chemical treatment.
It matters as a baseline — hermetic (airtight) storage bags and metal silos inherently limit pest access and moisture exchange better than open sacks or traditional mud structures, but even good storage type can't fully offset grain that goes in wet or already infested.