What is Orden FOM/1882/2012?

It is the Spanish regulation that establishes the methodology for adjusting road transport prices based on diesel fuel price variation. It applies to all road freight transport contracts in Spain.

Where do the diesel prices come from?

The prices are pre-tax (PAI — Precio Antes de Impuestos) weekly averages published by the Ministry of Transport (MITMA). They reflect the actual cost of diesel before taxes and are the official reference for transport price adjustments.

What does the 5% threshold mean?

The regulation establishes that price adjustments below a 5% variation may not be mandatory. However, parties can agree to apply adjustments for any variation level in their contracts.

Which vehicle factor should I use?

The factor depends on the vehicle's maximum authorized weight (PMA). Heavier vehicles (> 20 Tn) use a 0.30 factor because fuel represents a larger share of operating costs. Lighter vehicles (≤ 3.5 Tn) use 0.15.

Can the adjustment be negative?

Yes. If diesel prices decrease between the contract date and the transport date, the adjustment is negative — meaning the final transport price is lower than the original.

Orden FOM/1882/2012

Diesel Price Variation Calculator

Calculate how changes in diesel prices affect your transport costs, based on Spain's official methodology (Orden FOM/1882/2012) and weekly pre-tax prices published by MITMA.

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What is the Diesel Price Variation Clause?

The Orden FOM/1882/2012 establishes an official methodology for adjusting road freight transport prices based on changes in diesel fuel costs. This mechanism protects both carriers and shippers from fuel price volatility.

The formula calculates the percentage change in diesel prices between the contract date and the transport date, then applies a vehicle-type-specific factor to determine the price adjustment.

How Does the Calculation Work?

The adjustment uses three inputs: the pre-tax diesel price (PAI) at contract time, the PAI at transport time, and a factor that depends on the vehicle category. The regulation defines four vehicle categories with different fuel cost weightings.

Adjustment = ((Effective Price − Contract Price) ÷ Contract Price) × Vehicle Factor × Transport Price

Diesel Price Variation Calculator

What is the Diesel Price Variation Clause?

How Does the Calculation Work?

Frequently Asked Questions