Significant Figures and Rounding Checker with LOD/LOQ Reporting
Turn measured values, instrument resolution, standard deviation, and rounding rules into notation you can use in reports.
Quick Examples
Check the main cases before you startRound from resolution
Below LOD
Round from standard deviation
How To Use It
- Enter the measured value and add a unit if you need one in the final text.
- Enter either instrument resolution or standard deviation, then choose the rounding rule.
- If LOD or LOQ matters, enter the threshold and pick the reporting style you want to compare.
- Copy the recommended notation and share the short reason or full analysis report when needed.
Glossary
Significant figures
Digits that can be justified by the precision of the measurement.
Measurement resolution
The smallest readable increment from the instrument or display. It becomes one candidate basis for reporting precision.
Standard deviation (σ)
The spread of repeated measurements. Round σ to 1 or 2 digits first, then align the reported value to the same place.
LOD
Limit of detection. If the value is below this threshold, the tool prioritizes non-quantitative reporting candidates.
LOQ
Limit of quantification. Values below this threshold may be detectable but not suitable as reported quantitative values.
Decision Logic
- Resolution basis = the resolution value you enter
- Sigma basis = the last significant place after rounding σ to 1 or 2 digits
- Recommended quantum = chosen from resolution, sigma, or the coarser requirement
- Rounded value = input value rounded to the recommended quantum with the selected rule
- If value < LOD, show below-LOD candidates. If value < LOQ, show below-LOQ candidates.
FAQ
Can I save settings for our reporting standard?
Yes. You can save rule presets in the browser and export or import them as JSON.
How does the tool report values below LOD?
It offers common candidates such as less-than-LOD notation, ND, and below-LOQ wording. Use the wording required by your standard.
Can I change the number formatting style?
Yes. You can follow the browser default, switch to Japanese style, European style, or remove grouping entirely.
What if I enter both resolution and standard deviation?
You can prioritize resolution, prioritize standard deviation, or use the coarser requirement. The default is the coarser requirement.
Does the tool send data to a server?
No. Calculation, presets, and recent history stay in your browser.
Important Notes
- This tool suggests notation from common rounding and reporting practices.
- If your internal standard, customer requirement, regulation, test method, or SOP says otherwise, follow that first.
- LOD and LOQ reporting practices differ widely by field and standard, so the tool presents candidates instead of claiming a single correct answer.