# CamionDATA Dieselfloater Calculator

> A public German-language calculator for diesel surcharges and discounts in road freight. It supports a proportional fuel-cost-share model and a completed-price-band model.

- Interactive calculator: https://camion-data.com/rechner/dieselfloater
- Canonical documentation: https://camion-data.com/rechner/dieselfloater.md
- Language: German UI, English machine-readable documentation
- Currency: EUR
- Price basis: net amounts
- Diesel price unit: EUR per litre or EUR per 100 litres

## How to use the interactive calculator

1. Choose "Kostenanteil" for the proportional model or "Preisstaffel" for completed bands.
2. Enter the net freight price, base diesel price, and current diesel price.
3. Enter either the fuel-cost share or the band width and adjustment per band.
4. Record the contractual source and reference period.
5. Read the percentage adjustment, euro adjustment, and adjusted net freight price in the result panel.

The controls have accessible German labels. The calculator component performs the arithmetic in the browser and does not require an account.

## Shared inputs

- freightPrice: original net freight price in EUR
- basePrice: contractual base diesel price
- currentPrice: diesel price for the contractual comparison period
- referenceSource: source named in the contract, such as Destatis or another agreed series
- referencePeriod: month or period used for the current price

Base and current prices must use the same unit and price basis. The calculator normalizes litre values to EUR per 100 litres internally.

## Fuel-cost-share model

Additional input:

- fuelShare: contractual diesel share of the freight price as a percentage from 0 to 100

Formula:

```text
relativePriceChange = (currentPrice - basePrice) / basePrice
adjustmentRate = relativePriceChange * (fuelShare / 100)
adjustmentAmount = freightPrice * adjustmentRate
adjustedFreight = freightPrice + adjustmentAmount
```

Worked example:

```text
freightPrice = 1000.00 EUR
basePrice = 130.00 EUR/100 l
currentPrice = 150.00 EUR/100 l
fuelShare = 30%

relativePriceChange = 15.384615%
adjustmentRate = 4.615385%
adjustmentAmount = 46.153846 EUR
adjustedFreight = 1046.153846 EUR
displayed adjusted freight = 1046.15 EUR
```

## Completed-price-band model

Additional inputs:

- bandWidth: diesel-price change represented by one contractual band
- percentPerBand: freight-price adjustment for each completed band

Formula:

```text
priceDifference = currentPrice - basePrice
completedBands = truncateTowardZero(priceDifference / bandWidth)
adjustmentRate = completedBands * (percentPerBand / 100)
adjustmentAmount = freightPrice * adjustmentRate
adjustedFreight = freightPrice + adjustmentAmount
```

Worked example:

```text
freightPrice = 1000.00 EUR
basePrice = 130.00 EUR/100 l
currentPrice = 142.00 EUR/100 l
bandWidth = 5.00 EUR/100 l
percentPerBand = 0.5%

priceDifference = 12.00 EUR/100 l
completedBands = 2
adjustmentRate = 1.0%
adjustmentAmount = 10.00 EUR
adjustedFreight = 1010.00 EUR
```

The formula counts only completed bands and truncates toward zero for both increases and decreases. An agent must check that this matches the wording of the user's contract.

## Outputs

- direction: surcharge, discount, or no change
- diesel-price difference
- relative diesel-price change or completed band count
- freight adjustment in percent
- freight adjustment in EUR
- adjusted net freight price

The UI rounds displayed currency values to two decimal places. It calculates with unrounded values.

## Source and legal limits

Destatis publishes several monthly German producer-price series for diesel in EUR per hectolitre, each with defined delivery volumes and trading conditions. A contract may name a different source, price basis, period, rounding rule, or treatment of falling prices. The calculator performs arithmetic only. It does not verify the validity or interpretation of a price-adjustment clause and must not be described as legal advice.