Ironing symbols
The iron family tells you whether ironing is permitted, the maximum sole-plate temperature, and whether steam is forbidden. Read the marks inside the iron separately from marks underneath it. Dots control temperature, while crossed steam strokes below the iron control steam.
Ironing appears fourth in the standard row, after the drying square and before the professional-care circle. By the time you reach it, you are reading a finishing instruction rather than a washing or drying method. The guide library shows this position in the full five-shape sequence and can help when a label has no spacing between families.
- Iron, any temperature ASTM explicitly defines the blank iron as 'Iron - Any.' Current ISO tables define ironing temperatures with dots and do not explicitly define a blank iron.
- Iron on low (one dot) One dot allows ironing up to 120°C under ISO 3758:2023 or 110°C under ASTM D5489.
- Iron on medium (two dots) Two dots allow ironing up to 160°C under ISO 3758:2023 or 150°C under ASTM D5489.
- Iron on high (three dots) Three dots allow ironing up to 210°C under ISO 3758:2023 or 200°C under ASTM D5489.
- Iron without steam ASTM's no-steam modifier sets no temperature by itself. ISO 3758:2023 uses one dot and a 120°C maximum for its no-steam treatment.
- Do not iron Don't iron this. Heat will damage the fabric or finish.
The iron outline establishes permission
ASTM explicitly defines an any-temperature instruction with a blank iron. Current ISO tables define ironing temperature with dots and do not explicitly define a blank iron, while secondary ISO guidance conflicts. Use the label's wording and regional context rather than assuming the empty outline settles the standard. One, two, and three dots set the low, medium, and high maximums.
A do-not-iron symbol puts a large cross over the entire iron. That cross forbids ironing. It is not a low-temperature instruction and it is not the same as switching steam off. Follow the garment's other care instructions for handling it rather than choosing a different direct-heat method on your own.
On a worn tag, trace the iron's pointed outline and flat base before reading the small marks. This keeps a nearby professional-care circle or drying square from lending its dots to the iron by mistake.
One, two, and three dots are temperature maxima
Current ISO 3758:2023 sets the one-, two-, and three-dot maxima at 120°C, 160°C, and 210°C. ASTM D5489 uses 110°C, 150°C, and 200°C. These are maximum sole-plate temperatures, not targets. You may iron cooler than the applicable mark allows.
The one-dot iron symbol is the lowest step, the two-dot iron symbol is the middle step, and the three-dot iron symbol is the highest step in this family. More dots permit a higher maximum. They do not tell you how many passes to make, how long to hold the iron in one place, or how much pressure to use.
Match the dot count on the care label to the iron's dot setting first. If the appliance gives only degrees, use the table for the standard behind the label. When you cannot identify that standard, choose the cooler 110°C, 150°C, or 200°C ceiling for the corresponding dot count. A newer, higher ISO figure is not permission to run hotter when the label's system is uncertain.
Steam marks sit underneath the iron
ASTM's no-steam modifier uses crossed vapor strokes below a blank iron and sets no temperature by itself. ISO 3758:2023's no-steam treatment includes one dot and a 120°C maximum. In both cases, turn steam off and use the temperature limit supplied by the applicable symbol or accompanying instruction.
Do not confuse this with the crossed iron. A large cross over the whole iron means do not iron. A small cross through the steam marks means iron without steam. One prohibition removes only steam from the permitted ironing method; the other removes ironing itself. Check what the cross actually covers before touching the appliance controls.
Temperature and steam remain separate constraints even when current ISO combines them in one glyph. Its one dot caps the sole-plate temperature at 120°C, and the crossed vapor strokes forbid steam. On the ASTM modifier, crossed vapor strokes bar steam without setting a temperature. Inspect the whole mark before choosing controls.
The glyphs match, but their temperature ceilings differ
ISO and ASTM draw the one-, two-, and three-dot irons the same way. The numbers split because ISO changed editions. ISO 3758:2012 used 110°C, 150°C, and 200°C, which are also the limits ASTM D5489 continues to use. ISO 3758:2023 raised each level by 10°C to 120°C, 160°C, and 210°C.
Many printed cards and online charts still reproduce the 2012 ISO table without naming the edition. That can make a current ISO reference appear to conflict with an older chart even though both show identical dot glyphs. Check the destination market, written instructions, and other regional marks on the label before choosing a numeric ceiling.
The dot count remains the part you act on. Use the matching dot position on the iron, and take the cooler numeric limit when the standard cannot be established. The 2023 ISO edition also introduced a distinct no-steam treatment with one dot, a 120°C maximum, and crossed steam marks. ASTM instead uses a no-dot no-steam modifier that does not itself assign a temperature.
Common ironing mix-ups
Check the shape and the placement of each mark before acting on a small or faded label.
One dot read as one pass
Dots set the maximum sole-plate temperature. They do not count strokes, passes, minutes, or pressure.
No steam read as do not iron
Crossed vapor marks do not forbid dry ironing. The ASTM modifier carries no dot or temperature; the current ISO treatment includes one dot and a 120°C maximum. A large cross over the whole iron forbids ironing.
An empty iron read as low heat
One dot marks low heat. ASTM explicitly defines a blank iron as an any-temperature instruction. Current ISO tables do not explicitly define it, and secondary ISO guidance conflicts, so check the label's wording and regional context.
An old chart read as current ISO
A chart showing 110°C, 150°C, and 200°C may be following ASTM D5489 or superseded ISO 3758:2012. Current ISO uses 120°C, 160°C, and 210°C. Do not choose the higher set unless you know the label follows the current ISO edition.
A dryer dot used for the iron setting
Identify the outside shape before counting. Dryer dots sit inside a circle within a square. Iron-temperature dots sit inside the iron body.
Other categories
Questions about ironing symbols
- Are iron temperatures targets or maximums?
- They are maximum sole-plate temperatures. Current ISO 3758:2023 sets one, two, and three dots at 120°C, 160°C, and 210°C. ASTM D5489 sets them at 110°C, 150°C, and 200°C. You can always choose a cooler setting.
- What if my iron dial uses fabric names instead of dots?
- Use the appliance's temperature guide to match its setting to the label's dot count. If the guide gives only degrees and you cannot identify the label's standard, use the cooler ASTM and older-ISO ceiling for that dot level.
- Does the no-steam symbol mean do not iron?
- No. ASTM's crossed-steam modifier still permits dry ironing and sets no temperature by itself. ISO's one-dot no-steam treatment permits dry ironing up to 120°C. A large cross over the whole iron is the do-not-iron symbol .
- Can I use a cooler iron setting than the dots allow?
- Yes. The dots show the hottest setting permitted, not a required setting. Stay at or below that limit and follow any no-steam instruction.
- Why does another chart list 110°C, 150°C, and 200°C for iron dots?
- Those are the ASTM D5489 maxima and were also used by ISO 3758:2012. ISO 3758:2023 raised the three levels to 120°C, 160°C, and 210°C. Many charts still show the superseded ISO figures, so check the named standard and edition rather than assuming the drawings settle the number.