Free endodontic reference

Endodontic file size and colour chart

Match common ISO file sizes to their colour and nominal tip diameter. For constant-taper instruments, calculate the diameter at any point along the 16 mm working portion.

ISO size reference

The size number is the nominal tip diameter in hundredths of a millimetre.

06

Pink

Ø 0.06 mm
08

Grey

Ø 0.08 mm
10

Purple

Ø 0.10 mm
15

White

Ø 0.15 mm
20

Yellow

Ø 0.20 mm
25

Red

Ø 0.25 mm
30

Blue

Ø 0.30 mm
35

Green

Ø 0.35 mm
40

Black

Ø 0.40 mm
45

White

Ø 0.45 mm
50

Yellow

Ø 0.50 mm
55

Red

Ø 0.55 mm
60

Blue

Ø 0.60 mm
70

Green

Ø 0.70 mm
80

Black

Ø 0.80 mm
90

White

Ø 0.90 mm
100

Yellow

Ø 1.00 mm
110

Red

Ø 1.10 mm
120

Blue

Ø 1.20 mm
130

Green

Ø 1.30 mm
140

Black

Ø 1.40 mm

Constant-taper calculator

Calculated diameter0.65 mmD(x) = tip diameter + taper × distance

Reference

Reading endodontic size and taper

What does ISO size 25 mean?

It designates a nominal tip diameter of 0.25 mm. The same hundredths-of-a-millimetre relationship applies to the other standard size numbers.

Why do the colours repeat after size 40?

The six-colour sequence white, yellow, red, blue, green and black repeats for larger standard sizes. Sizes 06, 08 and 10 use pink, grey and purple before that sequence.

What does a .04 taper mean?

For a constant .04 taper, diameter increases by 0.04 mm for each millimetre from the tip. A size 25/.04 file is therefore 0.25 mm at the tip and 0.65 mm at 10 mm from the tip.

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