About Us
Built for students, researchers, and educators who need fast, accurate, verifiable unit conversions — not estimates. Every value traces back to an international standard.
Our foundation
ISO · NIST · SI System
We don't approximate. Every conversion factor on this site is derived directly from ISO 80000 or NIST Special Publication 811 — the two definitive references recognized across scientific and engineering disciplines worldwide.
Primary Standard
ISO 80000 Series
International Organization for Standardization. Quantities, units, and symbols across physics, chemistry, mathematics, and engineering.
Primary Standard
NIST SP 811 (2008)
Guide for the Use of the International System of Units. Published by the National Institute of Standards and Technology, U.S. Dept. of Commerce.
Unit System
SI (Système International)
The modern metric system adopted by 60+ national metrology institutes. The global language of science since 1960.
Verification
Cross-referenced values
All conversion factors are verified against both source documents. Discrepancies trigger manual review before any value is published.
Accuracy & scope
Precision and Accuracy
Many online converters round values or use informal sources. We preserve the full precision specified in each standard — which matters when you're checking derivations, writing lab reports, or verifying published results.
100%
Values sourced from
official standards
0
User-submitted or
crowd-sourced data
SI
All base units conform
to the SI 2019 redefinition
Who this is for
Designed for the academic context
Fast check for a first-year student checking your homework or a researcher validating a manuscript.
Students
University & high school
Physics, chemistry, and engineering coursework. Lab reports that demand correct significant figures and standard units.
Researchers
Academic & industrial R&D
Data-checking against published tables. Replication of results across different unit conventions used in literature.
Educators
Lecturers & instructors
A reliable reference to point students toward — one that teaches the correct standard, not a simplified approximation.
Our method
How we add a conversion
We apply a consistent editorial process to ensure every new unit or category meets the same bar as the existing ones.
Source identification
We locate the authoritative definition in ISO 80000 or NIST SP 811. If a unit appears in both, we note any difference and use the BIPM-aligned value.
Exact factor extraction
Conversion factors are recorded with full precision as stated in the standard. We do not introduce rounding at this stage.
Cross-verification
The factor is checked against at least one independent authoritative table — e.g., BIPM, PTB, or NPL publications — before it is accepted.
Display precision
When displaying results, we apply rounding based on precision appropriate to each unit. The underlying exact value is always available on request.
References
Primary sources
These are the documents our conversion data is drawn from. You can access them directly to verify any value on this site.
ISO 80000-1
Quantities and units — Part 1: General. International Organization for Standardization, Geneva, 2022.
NIST SP 811
Guide for the Use of the International System of Units (SI). B.N. Taylor & A. Thompson, NIST, 2008.
SI Brochure
The International System of Units (SI), 9th Edition. Bureau International des Poids et Mesures (BIPM), 2019.
NIST SP 1038
The International System of Units (SI) — Conversion Factors for General Use. NIST, 2006.
Our principles
Accuracy and Transparency
No agenda.
We have no incentive to influence the result. The answer is always the answer.
Transparent sources
Every conversion links to its origin standard. You can always trace the chain back to the source.
Corrections welcomed
If you find an error, tell us. We'll verify against the standard and correct immediately if warranted.
