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Convert Kilograms to Tonnes - Weight Converter

This converter transforms a mass value entered in kilograms (kg) into metric tonnes (t) using the fixed SI relationship between these units. It is intended for use in engineering, logistics, laboratory reporting, and compliance workflows where a simple, auditable unit conversion is required.

The conversion is exact in mathematical terms but practical reporting should account for measurement uncertainty, instrument calibration, and the number of significant figures required by your context or regulatory standard.

Below you will find an authoritative explanation of the relationship, step-by-step calculation notes, examples, frequently asked questions, and citations to standards bodies for traceability and best practice.

Updated Nov 5, 2025

Interactive Converter

Convert between kilogram and tonne with precision rounding.

Quick reference table

KilogramTonne
1 kg0.001 t
5 kg0.005 t
10 kg0.01 t
25 kg0.025 t
50 kg0.05 t
100 kg0.1 t

Methodology

Kilogram (kg) is the SI base unit of mass; the metric tonne (symbol t) is defined as exactly 1000 kilograms. This is a fixed mathematical relationship in the International System of Units (SI).

For measurement workflows, maintain traceability to national measurement institutes and laboratory accreditations (for example, ISO/IEC 17025) when converting values used in regulatory reports, certificates, or safety documentation.

When reporting results, choose rounding and number of significant figures appropriate to instrument resolution and the uncertainty budget. Follow guidance from standards bodies (e.g., NIST, BIPM, ISO) for documentation and uncertainty statements.

Worked examples

1000 kg → 1 t (since 1000 ÷ 1000 = 1)

2.5 kg → 0.0025 t (2.5 ÷ 1000 = 0.0025)

1,234,567 kg → 1234.567 t (1,234,567 ÷ 1000 = 1234.567); round as needed for reporting

Further resources

External guidance

Expert Q&A

Is the conversion between kilograms and tonnes exact or approximate?

The mathematical conversion is exact: 1 tonne equals exactly 1000 kilograms. In practice, reported values may be rounded to reflect instrument resolution and measurement uncertainty.

How many significant figures should I report after converting?

Report significant figures based on the least precise component of your measurement chain and the stated uncertainty. For laboratory and regulatory use, document instrument resolution, calibration date, and uncertainty per ISO/IEC 17025 and local guidance.

What is the difference between a metric tonne and a short ton/long ton?

A metric tonne (t) equals 1000 kg. The US short ton and the UK long ton are different units based on pounds; they do not equal 1000 kg. Verify which 'ton' is required by your contract or regulation before converting.

Do I need to calibrate scales before using this converter for compliance?

Yes. Unit conversion does not replace the need for calibrated measurement instruments. For compliance and certifications, use calibrated equipment with traceability to national standards and retain calibration records as specified in standards such as ISO/IEC 17025 or local regulatory requirements.

How should I document uncertainty when converting values for reports?

Include the converted value, the measurement uncertainty (expanded or combined standard uncertainty as appropriate), the number of significant figures, and traceability information. Follow guidance from NIST, BIPM, and ISO on expressing and propagating uncertainty.

Sources & citations