Use this phosphine fumigant calculator to estimate label-based aluminum phosphide requirements for stored grain, grain bins, silos, warehouses, railcars, shipping containers and labeled rodent burrow fumigation. Calculate fumigant quantity, minimum exposure period and order quantities for Weevil-Cide®, Fumitoxin® and Phostoxin®, then submit a purchase request to FSS.
Calculate Your Fumigant Requirements
Select your product, site and conditions to estimate dosage, minimum exposure period and order quantity.
Supported fumigants include Weevil-Cide® and Fumitoxin® pellets and tablets, plus Phostoxin® pellets, tablets, tablet prepacs and prepac ropes.
Need pallet quantities? Email orders@fsszone.com for bulk availability, freight coordination and volume pricing on qualifying orders.
Calculator Sources & Important Label Information
Calculator rates reviewed: August 2026
Important: Calculator results are planning estimates only and may contain errors. Do not rely on this calculator as a substitute for the current product label or Applicator’s Manual. FSS does not warrant that calculator results are error-free or appropriate for every fumigation. Always independently verify the product, application site, application rate, exposure period and safety requirements before use. The current product labeling governs application, and it is a violation of Federal law to use a pesticide in a manner inconsistent with its labeling.
Metal phosphide fumigants release toxic phosphine gas and can present serious inhalation, fire and handling hazards. Follow the current product label and Applicator’s Manual for all requirements involving temperature, moisture or water contact, application procedures, monitoring, personal protective equipment, respiratory protection and the Fumigation Management Plan.
No RUP License? Consider Grain Protectants
Grain protectants are non-fumigant insect-control products that can be applied directly to labeled stored grains to provide long-term residual protection against stored-product insects. Unlike metal-phosphide fumigants, they do not release phosphine gas, and many provide protection for months after application. They are a practical option for farmers, elevators, mills, feed facilities and other grain handlers looking for long-term insect protection without performing a fumigation.
What Happens Next
Your calculated product and quantity are carried into Shop FSS, where you submit your applicator-license, shipping and intended-use details. No payment is taken.
We verify the applicator license, confirm product availability and shipping requirements, and contact you if anything is needed.
We follow up with order details, pricing and next steps before shipment.
Phosphine & Aluminum Phosphide Calculator FAQs
How much aluminum phosphide fumigant do I need?
The amount depends on the product, fumigation type, volume or commodity quantity, temperature and the label rate you select. The FSS calculator provides a label-based planning estimate and order quantity. Always verify the calculation against the current product label and Applicator’s Manual before application.
What is the difference between Phostoxin®, Fumitoxin®, Weevil-Cide® and phosphine?
Phosphine is the fumigant gas. Phostoxin®, Fumitoxin® and Weevil-Cide® are brand names for aluminum phosphide fumigant products that release phosphine gas when exposed to atmospheric moisture. Customers sometimes use “Phostoxin” generically when referring to phosphine fumigation, but packaging, formulations and label directions can differ. Always use the specific product’s labeling.
Do I need a pesticide license to purchase aluminum phosphide fumigants?
Yes. These products are Restricted Use Pesticides. FSS verifies the certified applicator and applicable certification information before the sale is completed.
Can this calculator be used for rodent burrow fumigation?
Yes. The calculator includes a Rodent burrows mode under Type of fumigation. Verify the target pest, use site and current label directions before treatment, and follow all label restrictions and applicable state requirements.
How does temperature affect phosphine fumigation and exposure time?
Temperature affects how quickly aluminum phosphide releases phosphine gas and how long the commodity or space must remain sealed. Lower temperatures generally require longer exposure periods, and labels set minimum temperatures below which fumigation must not begin. The product labeling controls — always confirm against the current label and Applicator’s Manual.
Do I need phosphine monitoring and safety equipment?
Fumigant labels specify monitoring, personal protective equipment and respiratory-protection requirements based on the product and the conditions of use. Phosphine measurements may be required for worker safety and are also useful for understanding gas concentrations during treatment. Follow the current label and Applicator’s Manual for your situation. FSS carries phosphine monitors, respiratory protection and related fumigation safety equipment.
Why do I still have live insects after a phosphine fumigation?
Live insects after fumigation can indicate that an adequate phosphine concentration-time exposure was not achieved throughout the treated space. Possible causes include leakage from inadequate sealing, uneven gas distribution, application problems or other treatment conditions. Phosphine resistance is also an increasing concern in some stored-product insect populations. High-range phosphine monitoring during a fumigation can help determine whether effective gas concentrations were reached and maintained at monitored locations. If a fumigation did not perform as expected, contact FSS for help evaluating the treatment.
What if I am not sure which fumigant or application rate to use?
If you are unsure which fumigant, formulation or labeled application rate is appropriate for your situation, contact FSS before treatment. Our fumigation specialists and entomologists can help you review the application, product options and current labeling. Ask an FSS Entomologist →
Our Product Lineup
Whether you are performing structural fumigation, grain bin treatment, trailer fumigation, or export treatments, we provide the products, documentation, and technical support needed to do the job correctly and safely. Check out our extensive product lineup.
