What is engineering logbook software?

Engineering logbook software is a digital replacement for a paper engineering notebook. It keeps dated entries organised by project, holds calculations and attachments beside the notes, and makes the whole record searchable and exportable.

Is a general notes app good enough for an engineering logbook?

It can be, with discipline. General notes apps do not enforce dates or project structure, do not evaluate calculations, and make it easy to edit old entries without trace. Dedicated logbook software builds those properties in.

Engineering logbook software

An engineering logbook is the dated record of how a design came to be. This page covers what a good one contains, where software does the job better than paper or general-purpose notes, and what to look for in a tool.

By the FactaLog team · Updated 4 October 2026

What is an engineering logbook?

An engineering logbook is a dated, chronological record of an engineer's work on a project: what was done, what was decided and why, the calculations and evidence behind those decisions, and what is still open. You write it as the work happens, while the details are fresh.

The habit comes from the bound laboratory notebook, and the purpose is the same. Anyone who reads the log later should be able to follow the reasoning that led to the design as well as the result. That reader might be you in eighteen months, a colleague taking over, a checker, a client or an expert witness.

What should an engineering logbook contain?

A useful entry answers six questions. Not every entry needs all six, but the decisions should.

Context: Date, project, who wrote it, and what prompted the work.
Work done: What you actually did: tested, modelled, measured, discussed, reviewed.
Decisions: What was decided, in one sentence a non-specialist could follow.
Rationale: Why: the requirement, constraint, calculation or test result that drove it, and the alternatives you rejected.
Evidence: The calculation, sketch, photo, datasheet or email that supports it, either attached or referenced precisely enough that anyone can find it again.
Open items: Assumptions still to verify, risks, and next actions.

The free engineering logbook template lays this out as a copyable structure, with a filled-in mechanical engineering example.

Why use software rather than paper or a general notes app?

Paper notebooks are hard to alter without leaving a trace, which is why they have lasted. They are much less useful once the page is written. You can't search them or share them easily, a 40-page datasheet won't fit, and finding the entry about the gearbox mount in notebook seven takes a while.

General-purpose notes apps (OneNote, Notion, Evernote, Word) make search easy but lose the logbook's structure. Pages are not tied to a date, projects blur together, calculations end up in a separate spreadsheet, and an old entry can be quietly rewritten. Many engineers make them work through personal discipline; we compare the approach in OneNote for engineering.

	Paper notebook	General notes app	Engineering logbook software
Dated, chronological by default	Yes	No, up to you	Yes
Organised by project	One notebook per project, or mixed	Up to you	Yes
Full-text search	No	Yes	Yes
Calculations that evaluate	No	Rarely	Should
Attachments with the entry	Stapled in	Yes	Yes
Evidence of later changes	Visible crossings-out	Usually none	Should, through version history or sealing
Time recorded against the work	Separately	Separately	Ideally built in

Design decisions and engineering rationale

The most valuable thing in a logbook is the reasoning behind decisions. Drawings and models record what the design is, and almost never why. When the why is lost, the next engineer either repeats the analysis or, worse, changes something that was the way it was for a reason.

A good decision record states the decision, the requirement or constraint that drove it, the alternatives considered and why they were rejected, the assumptions made, and the evidence. Our guide to recording engineering design decisions properly covers this in depth, including what is not worth recording.

Calculations, sketches and supporting evidence

A decision can only be checked against the evidence behind it. Keep the hand calculation, the FEA screenshot, the test photo and the supplier's datasheet with the entry that relied on them. If the calculation lives in a spreadsheet, record which file and revision. Better still, put the working in the entry itself so the two can't drift apart.

Chronological project history

Because each entry is dated, the logbook doubles as the project's history. That matters for variations and claims ("when did the client tell us about the higher duty cycle?"), for lessons learned, and for your own timesheets. Write on the day, and don't go back and tidy old entries. If something needs correcting, add a new entry that refers to the old one.

Consultancy and project handover

For consultancies, the logbook is also a business record. It shows the client what was done for the hours billed, lets another engineer pick up a project part-way through, and is where people look first when a job is questioned years later. If the logbook can be filtered to one project and exported as a PDF, a handover that used to take a week of digging can be done in an afternoon.

Example engineering logbook entry

2026-03-12 · Acme Conveyors · Drive end redesign · A. Engineer

Work done
  Reviewed bearing failures on Line 2 drive (3 failures in 14 months).
  Checked L10 life for current 6208 deep-groove bearing at revised load.

Decision
  Change drive-end bearing from 6208 to 22208 spherical roller.

Rationale
  Measured radial load 6.1 kN (was specified 3.5 kN) after the 2025 belt upgrade.
  6208 L10 at 6.1 kN, 255 rpm ≈ 9,800 h, which matches the observed failures.
  22208 E: same bore and OD (40 × 80), L10 well over 100,000 h, and tolerates the
  0.5° shaft misalignment we measured (deep-groove limit ~0.15°).
  Rejected: 6308 (90 mm OD needs a new housing, and only ~2× life); realigning shaft alone
  (doesn't address the higher load).

Assumptions / open
  Load taken from one day's measurement. Confirm over a full shift (action: JB, 19 Mar).
  22208 is 23 mm wide vs 18 mm. Check housing width and cover with workshop.

Evidence
  Load log 2026-03-10.csv · bearing calc (math block) · manufacturer datasheet 22208 E

Values above are illustrative.

How FactaLog approaches the problem

FactaLog is engineering logbook software for Windows, built by an engineer for engineers. Each day is a page; each entry belongs to a client and project. Calculations are written inline and evaluate as you type, with units. Images live with their entry, and links lead to the documents behind it. Everything is full-text searchable with Ctrl+K, and time is recorded against the entry you are working in.

It is local-first: your logbook is an SQLite database on your own computer, the free version needs no account or sign-up, and the app collects no telemetry. Entries can be sealed so that FactaLog can show later whether they have changed.