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SI prefix converter

Convert deci to milli

1 d = 100 m — to convert deci to milli, multiply by 100.

Deci to milli calculator

milli m100

1 d = 100 m

Deci to milli at a glance

Conversion

1 d = 100 m

Rule

× 100

Decimal shift

2 places right

Powers of ten

10⁻¹ → 10⁻³

Deci to milli formula and conversion factor

Every SI prefix is a whole power of ten. Deci is 10⁻¹ of the base unit and milli is 10⁻³, so the two are exactly 2 powers of ten apart. That makes the factor exactly 100 — not an approximation, and it never changes with the unit you are measuring.

m = d × 100

10⁻¹ ÷ 10⁻³ = 10² = 100

1 d    = 100 m
5 d    = 500 m
100 d  = 10,000 m
1000 d = 100,000 m

Deci to milli conversion table

The values people look up most often, converted exactly. Read down for deci (d), across for milli (m).

In words: 10 d is 1,000 m, 100 d is 10,000 m, 500 d is 50,000 m, 1000 d is 100,000 m, 2000 d is 200,000 m, and 5000 d is 500,000 m.

Deci to milli conversion table
Deci (d)Milli (m)
0.0009 d0.09 m
0.001 d0.1 m
0.005 d0.5 m
0.008 d0.8 m
0.01 d1 m
0.02 d2 m
0.05 d5 m
0.1 d10 m
0.2 d20 m
0.4 d40 m
0.5 d50 m
1 d100 m
2 d200 m
5 d500 m
7 d700 m
10 d1,000 m
20 d2,000 m
50 d5,000 m
100 d10,000 m
200 d20,000 m
250 d25,000 m
300 d30,000 m
400 d40,000 m
500 d50,000 m
800 d80,000 m
1,000 d100,000 m
2,000 d200,000 m
5,000 d500,000 m

How to convert deci to milli without a calculator

Move the decimal point 2 places to the right, padding with zeros if you run out of digits. Going to a smaller prefix always makes the number bigger, because it takes more of a smaller unit to describe the same quantity.

The check that catches almost every mistake: compare the two exponents before you write the answer. Deci is 10⁻¹, milli is 10⁻³. If the prefix you are moving to is smaller, the digits must grow. If your answer moved the wrong way, you divided when you should have multiplied — the failure mode behind more than one real unit-conversion incident.

Deci to milli FAQ

How do you convert deci to milli?
To convert deci to milli, multiply by 100. That is the same as moving the decimal point 2 places to the right. For example, 1 d = 100 m, and 5 d = 500 m.
How many milli are in 1 deci?
There are exactly 100 milli in 1 deci. Deci (d) is 10⁻¹ of the base unit and milli (m) is 10⁻³, so they sit 2 powers of ten apart — a factor of exactly 100, with no rounding.
Is 1 deci equal to 1 milli?
No. Deci and milli are different SI prefixes 2 powers of ten apart. Deci is 100 times larger than milli, so 1 d = 100 m.
Is the deci to milli conversion exact?
Yes. Every SI prefix is a whole power of ten, so deci to milli is exactly × 100 with no rounding. This calculator shifts the decimal exponent instead of multiplying in binary floating point, so a value like 1.001 d returns an exact result rather than one with a trailing rounding error.
Is deci bigger or smaller than milli?
Deci is bigger. Deci is 10⁻¹ and milli is 10⁻³, which makes deci 100 times larger. The number always moves the other way: a quantity written in the smaller unit uses the bigger number.