Math & Numbers
Calculate sample and population skewness to measure distribution asymmetry
skewness-calculatorMath & Numbers
Calculate sample standard deviation from sample variance using the n - 1 denominator
sample-standard-deviation-calculatorMath & Numbers
Calculate sample variance with the n - 1 denominator for estimating spread from a sample dataset
sample-variance-calculatorMath & Numbers
Calculate sample and population standard deviation, variance, coefficient of variation, and sigma intervals
standard-deviation-calculatorMath & Numbers
Sum arithmetic series, geometric series, or a custom list of terms
sum-of-series-calculatorMath & Numbers
Calculate arithmetic, geometric, and Fibonacci sequences, including the nth term, the first terms, and the partial sum
sequence-calculatorAI Tools
Convert scanned or image-heavy PDFs into Markdown with OpenDataLoader hybrid OCR, with a graceful fallback when the hybrid backend is unavailable
scanned-pdf-ocr-to-markdownMath & Numbers
Count significant figures and round numbers to a target number of significant digits
sig-fig-calculatorMath & Numbers
Calculate square roots, check whether a value is a perfect square, and verify the squared result
square-root-calculatorMath & Numbers
Add, subtract, multiply, and divide values written in scientific notation, then return standard, scientific, and engineering forms
scientific-notation-calculatorMath & Numbers
Convert numbers between standard decimal format and scientific notation, with optional engineering notation output
scientific-notation-converterDeveloper Tools
Compare StructTree-enabled and plain PDF extraction to see whether a document behaves like a tagged PDF and how much semantic structure it exposes
tagged-pdf-inspector