Torx and Drive Size Calculator

Torx, Phillips, Pozidriv, slotted and square side by side — with the ISO socket dimension and the driver point diameter kept apart, the external E series shown not to be the T series, and the drive size asked by head style because that is what decides it.

Last updated 24 Sep 2026

Torx and drive sizes

Screw and head style → every drive that fits

Screw sizeAmerican gauge numbers below a quarter inch, fractions above. The gauge is a rule rather than a table: the major diameter is 0.060 + 0.013·n inches, so a #10 is 0.190 in and 4.826 mm — within 3.6 per cent of an M5, which is why the two get confused and why a separate page on this site computes how far apart they really are.

Head style — and this matters more than the diameterThe recess has to fit inside the head, so a small head takes a small drive whatever the thread is. A #8 screw takes a T8 as a grub screw, where the recess has to fit inside a 4 mm cylinder, and a T25 as a socket cap screw, where the head is half as big again as the thread. Four sizes apart, same thread. Any chart with one Torx column per screw size is quietly assuming a head style.

Look up a Torx size directlyIndependent of the two fields above. T1 to T5, T7, T9, T27 and T35 are manufacturer sizes that ISO 10664:1999 does not carry — which does not make them unusual: T27 and T35 are two of the commonest sizes in a car.

…and an EXTERNAL Torx size, for the comparisonThe E series is a different family that goes on the OUTSIDE of a head and is driven by a socket. An E10 is not a T10 and is not related to one — the page prints both numbers so you can see how far apart they are.

Not a circuit: the three recesses drawn in plan at one scale, schematically. Look at where the driving face points in each. Torx has six near-radial faces, so essentially all of the torque you apply goes into turning and none into pushing the bit back out — which is why a Torx head half the size of a Phillips one carries more torque. Phillips has four tapered flanks, so part of the force is always trying to climb the bit out of the screw, and past some torque it does: that is cam-out, and it is the practical limit on a Phillips joint. Pozidriv is the same cross with parallel flanks and, on the right, the four short ribs at 45° that are the visual tell — if you can see those marks on the head, it is a Pozidriv screw and a Phillips bit will round it. The bar underneath is live: it is the across-lobes dimension of whichever Torx size you looked up, on a scale of nought to 25 mm, with the socket dimension, the driver point diameter and the clearance between them printed below.

5.100mmExample

A #10 socket cap screw, with a T27 and an E10 looked up beside it

A lookup, two standards, and one rule that is not a table

Screw gauge n → major diameter = 0.060 + 0.013·n inches · clearance = A_socket − d_driver

A: ISO 10664’s dimension across the lobes of the SOCKET — the hole in the screw. 1.75 mm at size 6 and 22.40 at size 100. The standard does not control it with a tolerance: it controls the recess with a GO and a NOT GO gauge, and at size 6 those are 1.695–1.709 and 1.778–1.785 mm
d_driver: the point diameter of the TOOL, which is the number most published Torx charts are actually printing. It is 1 to 4 per cent below A, because it has to go in. Two distributors’ catalogues agree on it to 0.03 mm
0.060 + 0.013 n: the American screw gauge rule, in inches. It is a rule and not a table, and it reproduces every printed gauge diameter exactly: #6 is 0.138 in, #10 is 0.190 in. A #10 is 4.826 mm, which is 3.6 per cent under an M5
type H, type Z: ISO 4757’s two cross recesses — Phillips and Pozidriv. The standard defines the RECESS; ISO 8764-1 is a separate standard for the driver tip that goes into it, and DIN 5260 is the German blade form. Naming the wrong one describes the wrong object
head style: the variable this page exists to put in. The recess must fit inside the head, so a grub screw and a socket cap screw of the same thread take Torx sizes several steps apart. Any chart with one Torx column has silently chosen a head style for you

Worked example

A #10 socket cap screw, with a T27 and an E10 looked up beside it
THE SCREW. A #10 gauge is 0.060 + 0.013 × 10 = 0.190 inches, which is 4.826 mm. Not an M5: an M5 is 5.000, so the two are 3.6 per cent apart on major diameter, which is enough that an M5 will not enter a #10 nut
THE DRIVE. From Wiha's chart, a #10 SOCKET CAP screw takes a T27. Change nothing but the head style and the answer moves a long way: the same #10 thread as a grub screw takes a T10, as a pan head a T25 and as a flat head a T20. The recess has to fit inside the head, and a socket cap head is one and a half to one and three quarter times the thread diameter while a grub screw has no head at all
THE DIMENSION. A T27 is 5.10 mm across the lobes. Note two things about that size. It is not in ISO 10664:1999 at all — the standard's table jumps from 25 to 30 — and yet it is one of the commonest sizes in a modern car. And the recess is 1.057 times the screw's own diameter, which is why the drive is the strong part and the thread is not
THE TOOL IS NOT THE HOLE. Two distributors print the T27 driver point diameter as 4.99 mm. That is 0.11 mm smaller than the socket, or 2.2 per cent. It has to be, or the bit would not go in. Almost every Torx chart on the web is one of these two columns and does not say which, and the gap between them is larger than the gauge window the standard allows on the recess
AND AN E10 IS NOT A T10. The external E series is a different family: the lobes are on the OUTSIDE of the head and a socket goes over it. An E10 is 9.30 mm across the lobes against a T10's 2.80 mm — 3.32 times the size, for the same digits. An E10 is used on M8 screws; a T10 on #4 to #5. If someone hands you an E-series socket set expecting it to cover T sizes, it will not cover any of them
WHAT TO DO WITH THE OTHER DRIVES. The same #10 screw takes a PH3 Phillips or a PZ3 Pozidriv — the same number, and they are NOT the same recess and do not interchange. Slotted, it takes a 7.9 mm blade. Square, a #2. The table on this page runs the full cross-reference, and hex and Allen sizes are covered elsewhere on this site rather than here

The two Torx tables, side by side

Two columns, two sources, and they are not the same measurement. A and B are ISO 10664:1999’s own nominal dimensions for the SOCKET, read from a published copy of the standard and checked row by row against a second source that prints the same sixteen values. The driver column is the tool, from two independent distributors’ catalogues that agree with each other to 0.03 mm. The difference between them is the clearance, which runs about 1 to 4 per cent of A and is what lets a bit into a screw — and it is bigger than the gauge window the standard allows on the recess itself, so the two tables cannot be reconciled by tolerance. If a chart you are reading does not say which of these it is printing, it is usually the driver column, because tool makers publish more than standards bodies do. The last column is worth reading too: ISO 10664:1999 designates its sizes by a plain socket NUMBER with no T, and four of the sizes the trade cannot do without — T7, T9, T27 and T35 — are not in its table at all. T27 and T35 are among the commonest sizes in a modern car. These dimensions come from a published standard’s table, not from a formula. The standard itself is cited below and the printed values are attributed to the catalogue they were taken from; a different publisher may round differently in the last digit. The same designation can mean different dimensions in different standards families — ANSI against ISO, inch against metric, one national standard against another. The family used here is named beside every figure; check which one your part was made to.
Size	A, across the lobes (mm)	B (mm)	Driver point diameter (mm)	Clearance (mm)	Clearance as % of A	In ISO 10664:1999?
T6	1.750	1.270	1.685	0.065	3.71	yes
T7	2.100	—	1.995	0.105	5.00	no — manufacturer size
T8	2.400	1.750	2.305	0.095	3.96	yes
T9	2.600	—	2.495	0.105	4.04	no — manufacturer size
T10	2.800	2.050	2.730	0.070	2.50	yes
T15	3.350	2.400	3.265	0.085	2.54	yes
T20	3.950	2.850	3.860	0.090	2.28	yes
T25	4.500	3.250	4.430	0.070	1.56	yes
T27	5.100	—	4.990	0.110	2.16	no — manufacturer size
T30	5.600	4.050	5.520	0.080	1.43	yes
T35	5.900	—	—	—	—	no — manufacturer size
T40	6.750	4.850	6.650	0.100	1.48	yes
T45	7.930	5.640	7.820	0.110	1.39	yes
T50	8.950	6.450	8.830	0.120	1.34	yes
T55	11.350	8.050	11.220	0.130	1.15	yes
T60	13.450	9.600	13.250	0.200	1.49	yes
T70	15.700	11.200	15.510	0.190	1.21	yes
T80	17.750	12.800	—	—	—	yes
T90	20.200	14.400	—	—	—	yes
T100	22.400	16.000	—	—	—	yes

Every drive that fits a given screw

Read across a row and the whole drive question for that screw is answered. Read DOWN the four Torx columns and the reason a single-column chart misleads becomes obvious: a #8 screw takes a T8 as a grub screw and a T25 as a socket cap screw, because the recess has to fit inside the head and a grub screw has no head at all. The Phillips and Pozidriv columns carry the same number for every row, which is exactly the trap — the SIZE designations run in parallel and the recesses do not interchange. For a metric reader: the gauge diameters are 0.060 + 0.013n inches, so #6 is 3.51 mm (call it M3.5), #8 is 4.17 (M4), #10 is 4.83 (M5) and #12 is 5.49 (M5.5, which is not a common metric size). A quarter inch is 6.35 mm and sits between M6 and M7. These dimensions come from a published standard’s table, not from a formula. The standard itself is cited below and the printed values are attributed to the catalogue they were taken from; a different publisher may round differently in the last digit.
Screw	Major dia (mm)	Torx, set screw	Torx, socket cap	Torx, pan head	Torx, flat head	Phillips	Pozidriv	Slotted blade	Square
#2	2.18	T3	—	T7	T6	PH1	PZ1	2.4 mm	—
#3	2.51	T5	—	T8	T7	PH1	PZ1	3.2 mm	—
#4	2.84	T6	T10	T9	T8	PH1	PZ1	3.2 mm	—
#5	3.17	T7	T10	T10	T9	PH2	PZ2	4.0 mm	#1
#6	3.51	T7	T15	T15	T10	PH2	PZ2	4.8 mm	#1
#8	4.17	T8	T25	T20	T15	PH2	PZ2	7.9 mm	#2
#10	4.83	T10	T27	T25	T20	PH3	PZ3	7.9 mm	#2
#12	5.49	T10	T27	T27	T25	PH3	PZ3	9.5 mm	#3
1/4	6.35	T20	T30	T30	T27	PH3	PZ3	9.5 mm	#3
5/16	7.94	T27	T45	—	T40	PH4	PZ4	11.1 mm	—
3/8	9.52	T30	T50	T45	T40	PH4	PZ4	11.1 mm	—
7/16	11.11	T40	T55	T50	T50	PH4	PZ4	12.7 mm	—
1/2	12.70	T45	T55	T55	T55	PH4	PZ4	12.7 mm	—

External Torx, and why an E10 is not a T10

Two different families that share a numbering style and nothing else. The E series is EXTERNAL: the lobes are on the outside of the head and a socket goes over it, which is why an E-size head can be shallower than a hexagon of the same strength and why it turns up on exhaust manifolds and flywheel bolts. The T series is internal. An E10 is 9.30 mm across the lobes; a T10 is 2.80 mm; the E number is 3.3 times the T number of the same digits, and the ratio is not even constant. Wikipedia’s Torx article puts it plainly: the external nominal sizing does not correlate to the T size. Torx Plus is a third family again — designated IP internally and EP externally, with a squarer lobe for more torque. A standard Torx driver will enter a Torx Plus recess and should not be taken to full torque in it, and a Torx Plus driver will not enter a standard Torx recess at all. The same designation can mean different dimensions in different standards families — ANSI against ISO, inch against metric, one national standard against another. The family used here is named beside every figure; check which one your part was made to.
External size	Across the lobes (mm)	Inch screw	Metric screw	Same-numbered internal size	Its dimension (mm)	E ÷ T
E4	3.80	#6	M3	T4	1.35	2.81×
E5	4.70	#8	M4	T5	1.50	3.13×
E6	5.60	#10	M5	T6	1.75	3.20×
E7	6.10	—	—	T7	2.10	2.90×
E8	7.40	1/4 in	M6, M7	T8	2.40	3.08×
E10	9.30	5/16 in	M8	T10	2.80	3.32×
E12	11.10	3/8 in	M10, M11	no T12 exists	—	—
E14	12.80	7/16 in	M12	no T14 exists	—	—
E16	14.70	1/2 in	—	no T16 exists	—	—
E18	16.60	9/16 in	M14	no T18 exists	—	—
E20	18.40	5/8 in	M16	T20	3.95	4.66×
E24	22.10	3/4 in	M18, M20	no T24 exists	—	—

Phillips against Pozidriv against Torx

The Pozidriv paragraph is the useful one. The two systems use the SAME size numbers and are not interchangeable, and the failure is quiet rather than obvious: the screw goes in, it feels tight, and the recess is being destroyed. The tell is on the screw, not the driver — four short lines at 45° to the cross, in the flat of the head, which the Pozidriv punch leaves and the Phillips punch does not. On cam-out, one correction to a story that is repeated everywhere: Phillips is often said to have been DESIGNED to cam out, so that an assembly line could not overtighten an aluminium aircraft. It does cam out, that is the whole practical difference from Torx, and the design-intent claim has no good evidence behind it and does not appear in the original patents. What is certainly true is the geometry: a tapered flank turns torque into axial force and a radial one does not, and that is why Torx transmits more torque from a smaller head. The same designation can mean different dimensions in different standards families — ANSI against ISO, inch against metric, one national standard against another. The family used here is named beside every figure; check which one your part was made to.
	Phillips (ISO 4757 type H)	Pozidriv (ISO 4757 type Z)	Torx (ISO 10664)
The recess	Four radial slots, tapered flanks, rounded corners, a pointed centre	The same four slots PLUS four smaller ones at 45°, parallel flanks, a blunt tip	Six lobes, near-radial contact faces, no taper at all
The visual tell	Just the cross	Four short tick marks between the arms of the cross, at 45°. If you can see them it is Pozidriv	A six-pointed star
Contact angle	The flank is tapered, so the driving force has a component pushing the bit OUT of the recess	The flanks are parallel, so much less of the force pushes the bit out	The faces are nearly radial, so essentially none of it does
Cam-out	Yes, and at a torque that depends on how hard you push. It is the practical limit on a Phillips joint	Much less than Phillips, which is what it was changed for	By design, no. The bit does not climb out; it twists off or the screw fails first
Wrong bit in it	A Pozidriv bit in a Phillips screw touches on the wrong flanks, sits proud and cams out early	A Phillips bit in a Pozidriv screw fits loosely, contacts on a small part of the flank and rounds the recess	A Torx Plus driver will not enter; a Torx driver in a Torx Plus screw is loose and must not be taken to full torque
Torque for a given head size	Lowest of the three	Higher than Phillips	Highest by a wide margin, which is why it took over in volume assembly
Sizes	PH0 to PH4	PZ0 to PZ5	T1 to T100 internally, E4 to E24 externally, IP and EP for Torx Plus

Two Torx tables, two cross recesses that will not interchange, and the head style that decides the size

Hex and Allen sizes are covered elsewhere on this site. This page is about the other drive systems — the hexalobular Torx family, the two cross recesses, slotted and square — and about the cross-reference between them, which is the thing that is hard to find and easy to get wrong.

There are two Torx tables in circulation and hardly anybody says which one they are printing. ISO 10664 gives A, the dimension across the lobes of the SOCKET: 1.75 mm at size 6, 4.50 at 25, 22.40 at 100. Tool catalogues give the point diameter of the DRIVER, which is a different measurement of a different object and runs 1 to 4 per cent smaller, because the bit has to go into the screw. Two distributors’ driver tables agree with each other to 0.03 mm and disagree with ISO’s socket figure by up to 0.15 — more than the GO/NOT GO window the standard allows on the recess itself, so the discrepancy is not a tolerance and cannot be split. Both columns are on this page, labelled, with the clearance between them computed. If you are checking a recess, use A. If you are checking a bit, use the driver column. If a chart does not say, it is probably the driver.

Phillips and Pozidriv are not interchangeable, and this is the most useful paragraph on the page. ISO 4757 defines exactly two cross recesses: type H, which is Phillips, and type Z, which is Pozidriv. They use the same size numbers, 0 to 4, and they fit each other badly in both directions. A Phillips driver in a Pozidriv screw is loose: it contacts on a small part of the flank, it cams out early, and it rounds the recess. A Pozidriv driver in a Phillips screw contacts on the wrong flanks, sits proud, and does the same thing faster. The tell is on the SCREW and it takes a second to learn: a Pozidriv head carries four short tick marks at 45° to the arms of the cross, stamped by the punch into the flat of the head. A Phillips head has nothing but the cross. If the marks are there, use a PZ bit; if they are not, use a PH one. The failure mode when you get it wrong is not that the screw will not turn — it turns, it feels tight, and the recess is being destroyed while it does.

Cam-out, and one story that will not go away. A Phillips recess has tapered flanks, so part of the torque you apply becomes an axial force pushing the bit out of the screw; past a certain torque, at a given down-force, it climbs out. Pozidriv’s parallel flanks reduce that and Torx’s near-radial faces essentially eliminate it, which is why a Torx head half the size of a Phillips one will take more torque, and why volume assembly moved to it. That much is geometry and is not in dispute. What IS in dispute is the story that Phillips was deliberately designed to cam out so that assembly lines could not overtighten: there is no good evidence for it and it does not appear in the original patents. Cam-out is a consequence of the shape, whoever intended it.

The size that fits your screw depends on the head, not just the thread. This is the finding that makes a single-column cross-reference chart misleading. The recess has to fit inside the head with enough wall left to carry the torque, so the same thread takes very different drives in different head styles: a #8 screw is a T8 as a grub screw, a T15 as a flat head, a T20 as a pan head and a T25 as a socket cap screw. Four sizes, one thread. The table on this page carries four Torx columns for that reason, and the selector at the top asks for the head style before it answers. For a metric reader converting, the gauge rule is 0.060 + 0.013n inches: #6 is 3.51 mm, #8 is 4.17, #10 is 4.83 and #12 is 5.49, so the usual pairings with M3.5, M4, M5 and M5.5 are near misses rather than equivalences. How near is a different page’s subject on this site.

Frequently asked questions

How big is a T25 across the lobes?

4.50 mm as a socket, which is ISO 10664’s nominal A dimension, and about 4.43 mm as a driver point, which is what two distributors’ catalogues print. Both figures are correct and they are measurements of different objects — the hole in the screw and the tool that goes into it. The 0.07 mm between them is the clearance. ISO 10664 does not put a tolerance on A at all: it controls the recess with a GO and a NOT GO gauge, which at the smallest size are 1.695–1.709 mm and 1.778–1.785 mm around a 1.75 nominal.

Is an E10 the same as a T10?

No, and they are not even close. An E10 is an EXTERNAL Torx size — the lobes are on the outside of the head and a socket goes over it — and it measures 9.30 mm across the lobes. A T10 is an internal recess and measures 2.80 mm. The E number is roughly 3.3 times the T number of the same digits, and the ratio is not constant, so there is no conversion to learn. An E10 is used on M8 screws; a T10 on #4 to #5. An E-series socket set will not fit any T-series screw.

What Torx size fits an M5 screw?

It depends on the head. A metric socket cap screw around M5 — which is close to a #10 — typically takes a T27; a pan head T25; a flat head T20; and a grub screw T10. That four-size spread is the reason this page asks for the head style. Note also that M5 and #10 are not the same screw: #10 is 4.826 mm and M5 is 5.000, which is 3.6 per cent apart and enough to stop one entering the other’s nut.

How do I tell a Pozidriv screw from a Phillips one?

Look for four short tick marks in the flat of the head, at 45° to the arms of the cross. They are stamped by the Pozidriv punch and a Phillips head does not have them. On the bit rather than the screw, a Pozidriv driver has parallel flanks, a blunt tip and four extra ribs between the main blades; a Phillips driver has tapered flanks, a pointed tip and rounded corners. Getting it wrong does not stop the screw turning, which is exactly why it does damage: the screw goes in feeling tight while the recess is being chewed out.

Why does Torx take more torque than Phillips?

Because of where the driving faces point. A Phillips flank is tapered, so the force you put into it has a component along the screw axis pushing the bit out; past some torque, at whatever down-force you are applying, it climbs out and the recess takes the damage. A Torx lobe face is nearly radial, so almost all of the force goes into turning and essentially none into lifting the bit. The practical consequence is that a smaller Torx head carries more torque than a larger Phillips one, which is why volume assembly moved to it and why a Torx joint fails by twisting the bit off rather than by rounding the screw.

Are all Torx sizes in the ISO standard?

No. ISO 10664:1999 tabulates sixteen sizes — 6, 8, 10, 15, 20, 25, 30, 40, 45, 50, 55, 60, 70, 80, 90 and 100 — and designates them by socket number rather than with a T. T1 to T5, T7, T9, T27 and T35 are manufacturer sizes outside that table, which does not make them rare: T27 and T35 are among the commonest sizes in a car and T7 and T9 are everywhere in consumer electronics. Their dimensions come from tool makers rather than from a standards body, so where a dimension matters, measure the recess.

What about Torx Plus and security Torx?

Torx Plus is a later family with a squarer lobe for more torque and less wear, designated IP internally and EP externally. The compatibility runs one way: a standard Torx driver will enter a Torx Plus recess but fits loosely and should not be taken to full torque in it, while a Torx Plus driver will not enter a standard Torx recess at all. Security Torx is the same recess with a pin in the centre, which blocks a solid driver; the matching bits are hollow and are sold freely, so it is a deterrent rather than a security measure.

Related calculators

References

ISO 10664:1999, Hexalobular internal driving feature for bolts and screws. Copyrighted and cited by number. The sixteen nominal A and B values used here were read from a published copy of the standard and then checked, row by row, against Wikipedia’s Torx article, which prints the same sixteen A values independently. Two points from the standard itself are worth stating and are not tables: it designates its sizes by a plain SOCKET NUMBER rather than by “T”, and it controls the recess with GO and NOT GO gauges rather than with a tolerance on A — for socket No. 6 the gauge limits are 1.695 to 1.709 mm GO and 1.778 to 1.785 mm NOT GO, which brackets the 1.75 nominal.
ISO 4757:1983, Cross recesses for screws. Cited by number. It defines exactly TWO cross recesses — type H, which is the Phillips form, and type Z, which is the Pozidriv form — in sizes 0 to 4, with penetration gauging for both. It is the recess standard; ISO 8764-1:2004, Assembly tools for screws and nuts — Screwdrivers for cross-recessed head screws — Part 1: Driver tips, is the separate standard for the tool that goes into it, and DIN 5260 is the German blade-form standard. Three different documents, and a page that names the wrong one is describing the wrong object.
Intafast Ltd, Torx / Hexalobular guide, and Compel Group, Torx Size Chart (both read 29 September 2026). Two independent distributors’ tables of the DRIVER point diameter, which is a different number from ISO 10664’s socket A dimension and is the one most “Torx size charts” are actually printing. They agree with each other to 0.03 mm at every shared size (T6: 1.67 and 1.70; T10: 2.72 and 2.74; T15: 3.26 and 3.27) and sit consistently 1 to 4 per cent below the socket nominal — which is the clearance that lets the driver in, and is why the two tables must never be mixed.
Wikipedia, Torx (read 29 September 2026). Used for three things this batch could not get from the standard: the manufacturer sizes ISO 10664:1999 does not carry (T1–T5, T7, T9, T27, T35), the external E-series across-lobes dimensions, and the plain statement that “the external ‘E’ Torx nominal sizing does not correlate to the ‘T’ size”. Its internal A column agrees with the published ISO 10664 table at all sixteen shared sizes, which is what qualifies it as the second source for that column.
Wikipedia, List of screw drives (read 29 September 2026). The source for the Phillips and Pozidriv size-to-screw ranges, for the ISO 2380 slotted blade widths, and for the geometric difference between the two cross recesses: a Phillips driver has “slightly tapered flanks, a pointed tip, and rounded corners”, a Pozidriv driver has “parallel flanks, a blunt tip, and additional smaller ribs at 45° to the main slots”. It is also the source for the correction on this page’s cam-out paragraph: the story that Phillips was DESIGNED to cam out has “no good evidence” behind it and “is not mentioned in the original patents”.
Wiha Tools, Torx Screw Size Chart (read 29 September 2026). The source for the screw-size to Torx-size cross-reference, and for the finding that makes a one-column chart useless: the Torx size depends on the HEAD STYLE as much as on the diameter. Wiha prints nine head styles, and a #8 screw takes a T8 as a socket set screw and a T25 as a socket cap screw — four sizes apart on the same thread.
Accu Ltd, Pozidriv vs. Phillips, what’s the difference? (read 29 September 2026). The practical statement of the mismatch: a Phillips driver “may appear to fit into a Pozi screw” but the cam-out risk is much higher, and the visual tell is that a Pozidriv recess has eight radial slots — the four of the cross plus a secondary set of four at 45° — where a Phillips has four.
EngineerFix, Square Bit Size Chart (read 29 September 2026). The source for the square (Robertson) size to screw gauge mapping and its colour code: #0 yellow for gauge 3 and 4, #1 green for 5 to 7, #2 red for 8 to 10, #3 black for 12 and 14. It also says the thing that stops this page printing a dimension for them: “actual tip dimensions vary slightly between manufacturers”, and there is no single published across-flats to quote.