# CRA simplified logbook: 12-month base year plus 3-month sample

> How to keep a CRA-compliant logbook without logging every trip every year.

**Author:** Emily Thompson — Canadian Tax Specialist (CRA)  
**Published:** 2026-04-09  
**Updated:** 2026-04-28  
**URL:** https://quilometragem.com/blog/cra-simplified-logbook-12-month-base-year-plus-3-month-sample

**TL;DR:** How to keep a CRA-compliant logbook without logging every trip every year.

- The CRA recognises that asking sole proprietors and employees to log every business kilometre forever is heavy.
- Year 1: the full base-year logbook.
- In each subsequent year, log every business trip for a representative 3-month period (CRA suggests using the same calendar quarter as in the base year for stability).
- Base year (2024): - Q3 business-use %: 65%. - Full-year business-use %: 67%.
- Manual paper logs are accepted but rarely defensible at audit.

## The simplified method explained

The CRA recognises that asking sole proprietors and employees to log every business kilometre forever is heavy.[^cra-logbook-86] Their compromise: keep a **12-month base-year logbook** with every trip, then in subsequent years keep a **3-month representative sample** and extrapolate to the full year, provided the pattern is consistent (within 10% of the base year).

## Year 1: the full base-year logbook

For the first 12 consecutive months of business use of a vehicle (not necessarily a calendar year), record every business trip with:

- Date
- Destination
- Purpose (business reason)
- Kilometres

Also record total kilometres on the odometer at the start and end of the period to compute the business-use percentage:

**Business-use % = (Sum of business km) / (Total km in the period)**

This ratio becomes the baseline.

## Year 2 onwards: the 3-month sample

In each subsequent year, log every business trip for **a representative 3-month period** (CRA suggests using the same calendar quarter as in the base year for stability). Compute the sample's business-use % and apply this consistency check:

**| Sample % − Base-year same-quarter % | ≤ 10 percentage points**

If the difference is within 10 pp, you can extrapolate the sample's business-use % to the full year and deduct expenses on that basis. If outside 10 pp, you fall back to the full-year logbook.

## Worked example

Base year (2024):
- Q3 business-use %: 65%.
- Full-year business-use %: 67%.

2026 sample (Q3):
- Business-use %: 70%.

Check: |70% − 65%| = 5 pp → within 10 pp, so the sample is consistent. Apply 70% × (67% / 65%) = ~72.2% as the inferred 2026 full-year business-use %.

This 72.2% is then applied to total expenses (fuel, insurance, lease, maintenance, CCA) to compute the deductible portion.

## What CRA expects in an audit

- The full base-year logbook with every trip.
- The annual sample logbook(s) with every trip in the sample period.
- Odometer readings for the start and end of the base year and each sample period.
- A spreadsheet or system showing the consistency check and extrapolation.

## Tools that help

Manual paper logs are accepted but rarely defensible at audit. GPS-based digital tools — like Quilometragem — capture each trip with date, distance, route, business purpose and a tamper-evident hash, eliminating both data-entry error and integrity questions.

## When to switch back to full-year logging

- Major change in role (new territory, change from inside sales to outside sales).
- Major change in vehicle (much higher or lower mileage profile).
- A failed consistency check (gap > 10 pp).

After a 12-month full logbook is reset, the simplified method can resume.

## Bottom line

The simplified method is one of the few CRA accommodations that genuinely reduces compliance burden without sacrificing audit defence. Use it: one full base year, then 3-month samples thereafter. Total annual logging effort drops by ~75% with no loss of deduction.

## Sources

- [CRA — Motor vehicle records](https://www.canada.ca/en/revenue-agency/services/tax/businesses/topics/sole-proprietorships-partnerships/business-expenses/motor-vehicle-expenses/motor-vehicle-records.html) — Canada Revenue Agency (2026-04-28)