Fuel Price Breakdown Simulator: What a Litre Costs in France

On a litre of French fuel, more than half the price does not depend on the barrel: the excise is a fixed amount per litre, and the 20% VAT applies to the product and to the excise itself. This simulator makes that mechanism something you can handle. Set Brent, the euro-dollar rate and the refining and distribution margins, and watch the litre bar rebuild segment by segment, for diesel or SP95 gasoline (E5/SP98).

The default values reproduce the 3 July 2026 decomposition documented in our analysis of the French pump price, decomposed: a litre of SP95 at €1.873, of which 53.5% is tax.

What the tool computes

The pre-tax product adds three components: Brent converted into euros per litre (one barrel = 159 litres), the refining margin, and distribution costs (transport, retailer margin, energy-savings certificates, biofuel blending). On top sits the energy excise, fixed per litre: €0.6075 for diesel, €0.6902 for SP95 (the E5/SP98 rate), 2026 schedules outside Corsica (DGEC). The 20% VAT then applies to the sum of product and excise: a tax levied on a tax. At the defaults, SP95 comes to €1.873 per litre (53.5% tax) and diesel to €1.863 (49.3%), the UFIP national averages of 3 July 2026.

One methodological point: no official weekly series isolates the refining margin from the rest of the price. The default shown is therefore estimated as a residual, so the total matches the observed average price. How that margin forms, and why it weighs more than the barrel in oil profits, is covered in the dedicated analysis of refining margins.

What the Brent slider shows

Push Brent to $150: a litre of SP95 rises to €2.409, but the tax share falls to 45.3%. Bring it down to $20: diesel drops to €1.542 and the fiscal share climbs to 56.1%. The tax share rises when the barrel falls, a proportion effect, not a tax increase: the fixed floor simply weighs more in a smaller total. This is also why a move in crude never passes through in full: it only acts on the “product” fraction, less than half the price. For contrast, the US retail price, where taxes are about 18%, tracks the barrel far more closely; the underlying series are in the US regular gasoline retail price and US diesel retail price datasets.

Limits

The tool works on national average prices: differences between stations come from distribution and competitive density, not from taxation, which has been national and uniform outside Corsica since the regional modulation was abolished on 1 August 2025. E85 and LPG, subject to specific reduced excise rates, are out of scope. And the decomposition is accounting-based and instantaneous: it says nothing about how fast a move in crude reaches the pump; that pass-through asymmetry is measured in our test on French data.

Frequently asked questions

Why does the pump price fall less than the barrel?

Because the component that tracks crude (the refined product) is less than half the French price. The excise, fixed per litre, does not move; only the VAT levied on the product varies at the margin. A 10% drop in Brent therefore cuts the litre by only a few percent, which the slider makes directly visible.

Does the state collect more when the barrel rises?

Not through the excise, which is an amount per litre rather than a share of the price: a more expensive barrel leaves its revenue unchanged, or lower if consumption falls. Only VAT, which is proportional, rises mechanically with the pre-tax price: a distinction the public debate frequently conflates.

Go deeper

• The full decomposition of the French litre and the US comparison: where your fuel money goes.
• Do pump prices rise faster than they fall? The asymmetry measured on French data.
• Upstream mechanics: refining margins as the hidden driver of oil profits.
• Your own exposure: fuel burden calculator.
• The framework: commodity price formation.

Last updated — 6 October 2026