frbaremekm (R)

Dependency-free R package published by MaCalculatriceEnLigne. Author: Rédaction MaCalculatrice.

French tax mileage allowance scale ("bareme kilometrique"), used to deduct professional travel costs ("frais reels") from French income tax.

• Tax returns 2022 to 2026 (income years 2021 to 2025)
• Cars, motorcycles (more than 50 cm3) and mopeds
• 135 rates, three distance bands per horsepower class
• 20 % increase for 100 % electric vehicles

Installation

R 4.0 or later, base R only.

# install.packages("remotes")
remotes::install_github("tresor4k/fr-bareme-km-r")

Usage

library(frbaremekm)

# 2026 tax return (2025 kilometres), 5 CV car, 4 000 km
bareme_amount(2026, "automobile", 5, 4000)          # 2544

# Same car, 100 % electric
bareme_amount_electric(2026, "automobile", 5, 4000) # 3052.8

# Vectorised: both sides of the 5 000 km band limit
bareme_amount(2026, "automobile", 5, c(5000, 5001)) # 3180 3180.36

bareme_class("motocyclette", 4) # "cv3_4_5"
bareme_income_year(2026)        # 2025
bareme_source(2026)             # official text of the 2026 scale
nrow(bareme_rates())            # 135

Vehicles are named as in the source: "automobile", "motocyclette", "cyclomoteur". Inputs outside the scale (year, vehicle type, horsepower, distance) signal an error of class baremekm_out_of_scale and baremekm_year, baremekm_vehicle, baremekm_horsepower or baremekm_km.

The same computation is available online, in French, with the detail of each band: French mileage allowance calculator.

The rates are a port of the Go package baremekm, itself a port of the SWI-Prolog pack fr_bareme_km 1.0.0. R/rates.R is generated from the Go source (tools/gen_data.mjs) and cross-checked rate by rate (tools/crosscheck.mjs, 135/135 required); the tests replay each of the 135 facts of the pack and its test cases (R CMD check). Official sources: BOFIP BOI-BAREME-000001 (2022, 2023), DGFiP brochures pratiques IR (2024 to 2026), service-public.gouv.fr A14686 (2026). Dataset: doi:10.17632/5s59m9wycw.1 (CC BY 4.0).

This package is an aid to calculation, not tax advice. The official texts prevail.

Licence

Code: MIT, see LICENSE.md. The scale values are official French tax data (DGFiP, Licence Ouverte / Open Licence Etalab 2.0).