How to keep a lab notebook
By the Vara team · Updated 2026-10-21
In short: a lab notebook is written for you a year from now and for whoever takes over your project. A good entry shows what you did that day, which reagent lots you used, the parameters you actually used, where you departed from the plan, and where the raw data lives, well enough that someone could repeat it. Below are the eight things to record each time, the writing rules, paper vs digital, and the most common mistakes. To start filling one in, use the lab notebook template.
Why it matters
- When an assay suddenly stops working, a thin record means you cannot tell which step changed.
- Details that felt unimportant at the time, such as cell passage number, freeze-thaw history, antibody lot and dilution, or exposure time, are often the only clue two weeks later.
- Calculations done on scrap paper get lost; if a decimal point slipped, there is no way to trace where the error came from.
- Unpublished methods and lab know-how live in people's heads; when a postdoc leaves and the notebooks cannot be found, nobody can reproduce the result.
- An entry that only says "as before" is close to useless a year later, even to the person who wrote it.
What to record for every experiment
| Item | What to write | Example |
|---|---|---|
| Date and ID | Today's date, experiment ID, page number; for multi-day work, a new entry each day | 2026-10-21, WB-014, page 37 |
| Aim | The question this experiment is meant to answer, in one or two sentences | Check whether target protein drops after 24 h treatment |
| Materials and lot numbers | Reagent name, supplier, catalog number, lot number, date opened or made; passage number for cells | Primary antibody lot, BSA lot, HeLa passage 12 |
| Actual parameters | The amounts, concentrations, temperatures, times, and speeds you actually used, not just "as per protocol" | 20 µg loaded, primary 1:1000, 4 °C overnight (16 h) |
| Deviations | Anything that differed from the plan, why, and what it might affect | Blocking ran 1.5 h instead of 1 h while waiting for the imager |
| Raw data location | Instrument file names, folder path, photo numbers | NAS/WB/2026-10-21/WB-014_exp30s.tif |
| Results and observations | What you saw, observation first and interpretation second; record failed and negative results too | Target band fainter in treated lanes, loading control even |
| Next steps | What to change, which controls to add, how many repeats | Add a 48 h time point; compare new antibody lot before switching |
Examples are illustrative; use the values from your own experiment. For a fill-in version, see the lab notebook template.
Writing rules
- Record the same day: note numbers and times at the bench and write them up that day. Mark late entries as late, with the date.
- Never tear out pages or leave blanks: keep page numbers continuous and cross out unused space. A bound book loses fewer pages than loose sheets.
- Correct with a single line: keep the original readable and add the correction, date, and initials. No correction fluid, no scribbling out.
- Use permanent ink: many institutions require black or blue, never pencil. Follow your institution's rules.
- Write units in full: µL vs mL, µM vs mg/mL, rpm vs ×g. Replace "RT" and "overnight" with the actual temperature and duration where you can.
- Use one sample ID scheme: the same IDs on tubes, plates, and pages, with the scheme written at the front of the book, so anyone can match a tube to a page.
- Do the math in the notebook: write dilution and solution calculations on the page, not on scrap paper. You can work them out with the free lab calculators and copy the formula and result into the entry.
- Define abbreviations: keep a list at the front so someone else can read your notes.
Paper or digital
| Aspect | Paper notebook | Digital lab notebook |
|---|---|---|
| At the bench | Works with gloves on, survives splashes | Gloves off or a dedicated tablet; easy to skip when busy |
| Finding things | Hard to find one experiment from six months ago across several books | Search by name, date, or reagent |
| Reusing parameters | Copied by hand each time; copy errors are hard to spot | Copy last run's values, change what you need, and see what changed |
| Backup and handover | One copy; lost book means lost record, and books often leave with people | Depends on the tool and your backups; export matters |
| Institutional rules | Some universities require a bound notebook to be handed in | Regulated work needs a system your institution has validated |
Check your institution's rules first. Where there are none, a common setup is both: quick notes on paper or a phone at the bench, written up digitally the same day, with raw files filed by date and ID. For free digital options, see electronic lab notebooks compared.
Common mistakes
- Writing "as per protocol" without the actual amounts and times. After the protocol changes a few times, nobody knows which version you followed.
- Not recording changes made at the bench, such as a different antibody dilution or an extra 30 minutes of incubation. These are the first things to check when results differ.
- Copying "room temperature" or "overnight" from a paper instead of what actually happened.
- Switching reagent lots without noting it, then blaming technique when results shift.
- Naming raw files with a string of numbers, or keeping them only on a laptop or flash drive with no backup.
- Recording only experiments that worked, so the same failure gets repeated.
- Writing entries days later from memory, when the details no longer match.
Keeping digital records in Vara
Vara is one way to keep digital records, covering running and recording experiments:
- It turns a plan, protocol, or paper's methods into steps and parameters, and labels each parameter's source: from the source, AI inferred, or missing from the source. You review them before the experiment is created.
- Each run gets a run record with results, observations, and deviations. If you change an amount or time at the bench, tap "Changed this time" on the current step and add a line; the steps and parameters themselves stay the same.
- You can compare a run with the last one and see which parameters, steps, and notes changed.
- A sub-experiment can be exported as a Word or PDF run sheet to print as a bench record; see export a run sheet.
- It runs on the web and Mac; on a phone, open it in the browser.
To be clear: Vara has no electronic signatures and is not 21 CFR Part 11 compliant, so it does not replace a compliant electronic record system your institution requires. For regulated work, use the system your institution specifies. Vara also does not judge your experimental design; the conclusions are yours.
FAQ
What should I write in a lab notebook?+
For every experiment, record at least eight things: date and ID, aim, materials with lot numbers (and passage number for cells), the parameters you actually used, deviations from the plan, where the raw data files are, results and observations, and next steps. The test is whether you in a year, or the person who takes over, could repeat the work from that page alone.
How do I correct a mistake in a lab notebook?+
Draw a single line through it so the original stays readable, then write the correction next to it with the date and your initials. No correction fluid, no scribbling out, no torn pages. The same applies to digital records: a change should keep the old value and the time it changed.
Can I fill in my lab notebook later?+
Record on the same day whenever you can. If you are short on time, jot the key numbers and times down at the bench and write them up that day. If you add something later, mark it as a late entry with the date instead of making it look contemporaneous.
Can a digital lab notebook replace a paper one?+
It depends on your institution. Some universities require a bound notebook to be handed in, and regulated work (GLP, GMP, clinical) needs a validated system with electronic signatures and audit trails. Where there is no rule, many people use both: quick notes on paper at the bench, written up digitally the same day.
Should raw data go into the notebook?+
Key images such as gels or micrographs can be printed, dated, and taped in, but keep the original files separately. Write the file name and folder path in the notebook, and name files with the date and experiment ID so they can be found after a computer or a person changes.
Can I use Vara as a lab notebook?+
As one way to keep digital records, yes: Vara turns a protocol into steps and parameters, shows the source of each parameter (from the source, AI inferred, or missing from the source), records results, observations, and deviations for every run, and compares a run with the last one. Vara has no electronic signatures and is not 21 CFR Part 11 compliant, so it does not replace a compliant system your institution requires. Experimental design and conclusions are your call.