Meet the Author
Daniel Carter
I built SigFigLab because I spent years watching students get sig fig questions wrong, not because the concept is hard, but because every tool they found online either only counted, only rounded, or buried the rule explanation where nobody would read it. I wanted one clean calculator that counts, rounds, and calculates, and shows the reasoning behind every answer. That is what SigFigLab is.
Expertise
What I Know and Why It Matters Here
Every article and guide on SigFigLab is written from real teaching experience and direct knowledge of how significant figures are taught in science classrooms. These are the areas I draw on when I write about sig fig rules, rounding, and measurement precision.
Significant Figure Rules
I understand the full ruleset — non-zero digits, captive zeros, leading zeros, trailing zeros after decimals, ambiguous whole-number zeros, and scientific notation — and the edge cases teachers and students encounter most often.
Rounding to Significant Figures
Rounding errors are one of the most common reasons students lose marks on lab reports and homework. I know how rounding precision differs between decimal places and sig figs and where that distinction causes most confusion.
Sig Figs in Calculations
Addition, subtraction, multiplication, division, and mixed expressions each apply sig fig logic differently. I understand these rules at a level that lets me explain why an answer has a certain number of significant figures, not just what the number is.
Scientific and E Notation
Scientific notation is the clearest way to remove ambiguity in sig fig counting. I use it throughout the guides on this site to show students exactly where precision is and is not defined in a written number.
Chemistry and Physics Lab Standards
Sig figs exist because measurements have limits. Understanding that context — from analytical balances to ruler precision to stoichiometry — is what makes the rules on this site feel grounded rather than arbitrary.
Educational Tool Design
A calculator that gives an answer without an explanation teaches nothing. SigFigLab is built around the idea that every result should come with the rule that produced it — so students understand the method, not just the number.
Written by this author
Guides and Articles on SigFigLab
Every guide on this site is written from scratch based on direct knowledge of significant figures, measurement, and how these concepts are taught in science education. No content is published without expert review.
How I Write
Editorial Standards
Every guide starts from a question a real student or teacher would have when working with significant figures. I write the answer based on what I know from direct experience with science education, then structure it so the rule and the reason come first — not a long preamble.
I do not pad articles. If a rule has a short accurate explanation, the article is short. If a concept like ambiguous trailing zeros needs careful treatment, it gets the depth it deserves.
Accuracy Policy
How I Handle Corrections
Significant figure rules are well-established, but edge cases — especially whole-number trailing zeros and logarithms — can depend on classroom or lab convention. Where that is the case, I say so explicitly rather than giving a single answer as if it were universal.
If you find an error, an outdated explanation, or a case the guide does not cover, please use the contact page. Every article shows a last-updated date so you can tell when it was last reviewed.
Process
How Content Is Created on This Site
Knowing how an article was produced helps you decide how much to trust it. Here is the process behind every guide published on SigFigLab.
Start with a question students actually ask
Every article begins with a genuine question from the sig fig topic area — the kind a chemistry or physics student would type into a search bar during homework or before a lab report is due.
Write the answer from direct knowledge
I draw on firsthand knowledge of how significant figures are taught and applied in science education. I do not rewrite other explanations or copy examples from secondary sources.
Verify with the calculator itself
Where possible, I confirm the explanation against the SigFigLab calculator’s output. If the written guide and the tool give different results, I investigate and correct before publishing.
Flag convention-dependent cases clearly
Some sig fig decisions depend on teacher or lab convention — especially ambiguous trailing zeros and logarithm rounding. I always say so explicitly rather than presenting one answer as universally correct.
Review and update articles over time
Articles include a last-updated date. If the calculator changes, a convention is clarified, or a reader points out an error, the article is updated to match. No guide is published and ignored.
Transparency
What This Site Is and Is Not
SigFigLab is an independent educational tool site built and maintained by one person. It is not affiliated with any school, university, curriculum board, or testing organisation. There are no paid partnerships that influence how rules are explained, which examples are used, or which topics the guides cover.
The site earns revenue through display advertising. Ads are served automatically and have no effect on editorial decisions. The content of every guide is determined by what is accurate and useful for students, teachers, and science learners — not by advertising interest.
All guides and articles on SigFigLab are written by the site’s creator based on firsthand knowledge of significant figures and science education. Content is not outsourced, generated automatically without review, or assembled from other websites. Where scientific convention varies, that is stated in the article.
For questions about how this site works, how content is produced, or how to report an error, use the contact page. You can also read the privacy policy, terms of use, and disclaimer for full details.
Try the tool
Try the Calculator I Built
SigFigLab exists to make significant figures less confusing. Count sig figs, round to sig figs, or solve an expression — and read the rule behind every answer so you understand it, not just see it.