Sixty degrees and a narrow orb
A sextile is one sixth of the circle, 60 degrees of separation, and it carries the tightest orb of the five major aspects. Five degrees is the working figure, so Mars must sit between 55 and 65 degrees from Saturn for the aspect to register at all.
That narrowness is the single most important practical fact about the sextile. Where a conjunction tolerates eight degrees of slack, this one tolerates five, which means many separations that look close on a wheel do not actually qualify. If the widget above reports six degrees, most astrologers would not count it.
Mars sextiles Saturn twice per orbit, once approaching and once separating, and each occurrence holds for well under two weeks. Sextile signs are two apart, so they share a polarity but not an element: fire with air, or earth with water.
Compatible without being identical
Mars stands for initiative and the appetite for a fight, physical or otherwise. Saturn stands for form, delay and the willingness to keep at something long after the first enthusiasm has gone. A sextile connects them across compatible but unlike signs, which is why the tradition frames it as cooperation rather than fusion.
The usual reading here is practical competence that has to be learned. Someone with this aspect is described as able to organise their own effort, willing to accept a rule when the rule is useful, and generally without the resentment of authority that the hard aspects between these bodies often carry. What they are not described as is automatically disciplined. The sextile marks an ability that responds to training, and training has to happen.
Because fire pairs with air and earth with water, the two halves of the reading always come from different registers. A Mars in Aries sextile Saturn in Aquarius is drive meeting rules it broadly agrees with. Mars in Taurus sextile Saturn in Pisces is something slower and much less articulate.
What strengthens it and what does not
A sextile inside one degree behaves noticeably more like a trine, and most astrologers will read it that way. Beyond three degrees it fades quickly, and at four or five it usually only matters if something else in the chart points at the same theme.
House placement decides what is on offer. Mars in the third sextile Saturn in the fifth reads as applied concentration in a fairly specific area. Mars in the ninth sextile Saturn in the eleventh is much broader and often does not surface until later, when the person has a reason to use it.
Anything that connects to both ends raises the aspect's profile. A body sitting at the midpoint, or a planet trine to one end and sextile the other, tends to activate a sextile that would otherwise sit unused.
The bodies themselves, and reading your own chart
Two speed facts are worth carrying into any reading of this pair. Mars is retrograde for about two months in every two year cycle, and a retrograde Mars is generally read as reluctant to display itself, which suits a sextile poorly since the aspect needs to be taken up to do anything. Saturn moves about twelve degrees a year and stays in a sign for roughly two and a half years, which means its sign is shared by everyone born in that period and tells you very little about you specifically.
What does tell you something is the orb, the houses and whether anything else in the chart calls on the same two bodies. Those are the parts that vary from one person to the next.
The widget above reports the exact separation, so you can see whether this aspect is genuinely in your chart before you read any further into it.
Questions people ask about this
How tight does a sextile have to be?
Five degrees is the orb used here, which is the narrowest of the five major aspects. So Mars needs to be between about 55 and 65 degrees from Saturn. At six degrees or more, most astrologers would not treat it as a sextile at all.
What is the difference between a sextile and a trine?
Both are read as easy aspects, but a trine at 120 degrees joins signs of the same element and tends to operate by itself. A sextile at 60 degrees joins signs of different elements and is usually described as an opportunity that has to be taken up deliberately.
Does Mars sextile Saturn make someone disciplined?
The tradition reads it as capacity for discipline rather than discipline already present. It describes someone who can learn to structure their own effort and who does not fight rules on principle. Whether that capacity gets developed is not something the aspect says.
Which signs can hold this aspect?
Sextile signs are two apart, so they always share a polarity but not an element. That means fire with air, such as Aries and Aquarius, or earth with water, such as Taurus and Pisces.
How often does Mars sextile Saturn occur?
Twice in each Mars orbit of roughly two years, once before and once after the opposition. Because the orb is narrow, each occurrence lasts well under a fortnight, which makes it less common in charts than the wider aspects.
Can a sextile be too wide to matter?
Yes, more easily than any other major aspect. Past three degrees the effect is usually described as faint, and past five it is outside orb entirely. The exact figure from the check above is worth knowing before reading further.