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Kilograms to tonnes

Multiply kilograms by 0.001 to get tonnes.

1 kg = 0.001 tBIPM SI
kg
5t

5,000 kg = 5 t

How to convert kilograms to tonnes

The tonne is exactly 1000 kilograms — the metric ton. The kilogram is the SI base unit of mass, fixed since 2019 by defining the Planck constant as exactly 6.62607015×10⁻³⁴ J·s.

Worked example — 5,000 kg: 5,000 × 0.001 = 5 t.

Kilograms to tonnes table

Common conversions. The reverse table is on tonnes to kilograms.
KilogramsTonnes
100 kg0.1 t
500 kg0.5 t
1,000 kg1 t
2,000 kg2 t
5,000 kg5 t
10,000 kg10 t
20,000 kg20 t
50,000 kg50 t
100,000 kg100 t

Reverse and related

About kilograms and tonnes

Kilogram (kg)

1 kg = 0.001 t

Definition. The SI base unit of mass, fixed since 2019 by defining the Planck constant as exactly 6.62607015×10⁻³⁴ J·s

History and origin

The kilogram began in 1795 as the mass of one litre of water at the melting point of ice, and from 1889 was embodied in a platinum-iridium cylinder kept near Paris, the International Prototype Kilogram. In 2019 the SI retired that physical artefact and redefined the unit through a fixed value of the Planck constant, leaving its size unchanged.

Current use

It is the base unit of mass almost everywhere on Earth. The main everyday exception is the United States, where people weigh in pounds even though US science, medicine and industry work in kilograms.

Source: BIPM, The International System of Units (SI), 9th ed. (2019)

Tonne (t)

1 t = 1,000 kg

Definition. Exactly 1000 kilograms — the metric ton

History and origin

The tonne, or metric ton, was defined as exactly 1000 kilograms as the metric system spread, giving a convenient unit for heavy loads. It is accepted for use with the SI.

Current use

Tonnes measure bulk and freight weight, vehicle mass and industrial quantities throughout the metric world.

Source: BIPM, The International System of Units (SI), 9th ed. (2019)

Where people use this

Kilograms: body weight outside the US, groceries and produce, checked-luggage limits. Tonnes: bulk and freight weight, vehicles. 1000 kg is exactly 1 tonne.

How we know this is right
The factor is fixed by the standards that define the units, not chosen — so it is exact, not a measurement:
1 t = 1,000 kg, so 1 kg = 1 ÷ 1,000 = 0.001 t.

Every value is carried to full double precision; the display is rounded.

Both units are defined in BIPM, The International System of Units (SI), 9th ed. (2019).

Questions people ask

How many tonnes is 1000 kg?

1000 kg is exactly 1 tonne.

How many tonnes is 5000 kg?

5000 kg is 5 tonnes.

How many kg in a tonne?

One tonne is 1000 kilograms.

All kilogram conversions