VFR cruising altitudes come from 14 CFR 91.159: when you cruise VFR more than 3,000 feet above the surface and below 18,000 feet MSL, your altitude depends on your magnetic course. On a magnetic course of 0 through 179 degrees, fly an odd thousand plus 500 feet (3,500, 5,500, 7,500). On 180 through 359 degrees, fly an even thousand plus 500 feet (4,500, 6,500, 8,500). At 3,000 feet above the ground or lower, the rule does not apply.
Enter your magnetic course, planned altitude and the highest ground under your route, and the calculator shows the nearest cruising altitudes that 91.159 allows.
This guide is part of our Airspace and Weather guide. Picking a cruising altitude is one step in cross-country planning, right after you measure your course.
The rule in 14 CFR 91.159
Section 91.159 says that, except while holding in a holding pattern of 2 minutes or less or while turning, each person operating an aircraft under VFR in level cruising flight more than 3,000 feet above the surface must maintain the appropriate altitude or flight level below, unless otherwise authorized by ATC:
| Magnetic course | Cruise at | Examples |
|---|---|---|
| 0 through 179 degrees | Any odd thousand MSL plus 500 feet | 3,500, 5,500, 7,500 |
| 180 through 359 degrees | Any even thousand MSL plus 500 feet | 4,500, 6,500, 8,500 |
| Above 18,000 feet MSL | The altitude or flight level ATC assigns | Class A, IFR only |
The same table appears in the Aeronautical Information Manual, AIM 3-1-5.
When the rule applies, and when it does not
- VFR only. IFR flights use different altitudes, covered below.
- Level cruising flight. Climbs and descents are not cruise, and turns and holding patterns of 2 minutes or less are exempt.
- More than 3,000 feet above the surface. This is height above the ground under you, not MSL. At 3,000 feet AGL or lower, 91.159 does not restrict your altitude, although minimum safe altitudes, cloud clearances and airspace rules still do.
- Below 18,000 feet MSL. At 18,000 feet MSL you reach Class A airspace, where flights must operate under IFR (91.135).
- Unless ATC authorizes otherwise. In Class B airspace and terminal radar service areas, controllers may assign VFR altitudes that do not fit the rule. When they say “resume appropriate VFR altitudes,” you must return to a conforming altitude.
Because the 3,000-foot test is measured from the ground beneath you, it can switch on and off as terrain rises and falls along a route. The simplest way to stay legal is to plan a hemispheric altitude whenever any part of the cruise could be more than 3,000 feet above the ground.
Magnetic course, not heading
The rule is based on magnetic course, the direction of your track over the ground measured from magnetic north. The AIM labels that column “magnetic course (ground track).” It is not your heading, so a wind correction never changes which altitudes you may use. If you hold a heading of 183 degrees to make good a magnetic course of 175, you still fly an odd thousand plus 500.
To get magnetic course, measure the true course on your sectional chart with a plotter, then apply the variation from the nearest isogonic line. The FAA’s Pilot’s Handbook of Aeronautical Knowledge gives the classic aid “east is least, west is best”: subtract easterly variation and add westerly variation. Wind correction and compass deviation come after that and change only your heading. Our flight planning guide walks through the full sequence, and the wind correction angle guide covers the heading part.
Worked examples
| True course | Variation | Magnetic course | VFR cruising altitudes |
|---|---|---|---|
| 095 | 10 W | 105 | Odd plus 500: 3,500, 5,500, 7,500 |
| 268 | 4 E | 264 | Even plus 500: 4,500, 6,500, 8,500 |
| 175 | 8 W | 183 | Even plus 500, although the true course is east of south |
| 004 | 6 E | 358 | Even plus 500, although the true course is east of north |
The last two rows show why the conversion matters: near north and south, variation can move the magnetic course across the line that divides odd from even.
A memory aid for VFR cruising altitudes
Instructor memory aid: “East is odd, west is even, and VFR adds 500.” It is not FAA wording, so when it matters, go back to the regulation: 0 through 179 degrees magnetic is “east,” and 180 through 359 is “west.” Do not confuse it with “east is least, west is best,” which is about applying magnetic variation, not about altitudes.
- 0 to 179 degrees magnetic: odd thousands plus 500 (3,500, 5,500, 7,500, 9,500)
- 180 to 359 degrees magnetic: even thousands plus 500 (4,500, 6,500, 8,500, 10,500)
- Use: magnetic course (ground track), not heading
- Not required: while climbing, descending, turning or holding 2 minutes or less, or when ATC assigns otherwise
- Memory aid: east is odd, west is even, plus 500 for VFR
VFR vs. IFR cruising altitudes
IFR flights use whole thousands. In controlled airspace an IFR flight maintains the altitude ATC assigns, and controllers normally assign odd thousands for magnetic courses of 0 through 179 degrees and even thousands for 180 through 359 (FAA Order JO 7110.65, 4-5-2). In uncontrolled airspace, 14 CFR 91.179 sets the same pattern for IFR flights below 18,000 feet MSL. An IFR clearance for “VFR conditions on top” uses the VFR altitudes of 91.159.
| Magnetic course | VFR (91.159) | IFR, uncontrolled airspace (91.179) |
|---|---|---|
| 0 through 179 | Odd thousands plus 500 | Odd thousands (3,000, 5,000, 7,000) |
| 180 through 359 | Even thousands plus 500 | Even thousands (2,000, 4,000, 6,000) |
The result is built-in vertical spacing. An eastbound VFR airplane at 5,500 feet cruises 500 feet from IFR traffic at 5,000 and 6,000 and 1,000 feet from westbound VFR traffic at 4,500 and 6,500. That only works when everyone follows the rule, and it is never a substitute for looking outside.
Choosing the right altitude for your flight
91.159 narrows the choices. The rest of your planning picks one:
- Terrain and obstacles: stay above the minimum safe altitudes in 14 CFR 91.119, with room to glide to a landing spot.
- Clouds: cruise where you can keep the cloud clearances for your airspace, such as 500 feet below clouds in Class E below 10,000 feet MSL. See VFR weather minimums.
- Winds aloft: a headwind at one altitude can be a tailwind at another, so compare the forecast winds at each legal altitude.
- Airspace: check Class B shelves, Class C, special use airspace and TFRs along the route; sometimes they push you lower than you would like.
- Performance: high density altitude reduces climb performance, which can make the higher choices impractical.
Write the planned altitude for each leg on your nav log next to the magnetic course, and recheck it whenever a new leg’s magnetic course crosses north or south into the other half of the compass. The legal altitude can change at a single turn point.
Gear for planning your cruising altitude
What you'll need
Measure the course, work out the variation and wind, and keep the rule on your kneeboard.
Frequently asked questions
What is the VFR cruising altitude rule?
14 CFR 91.159 requires VFR aircraft in level cruise more than 3,000 feet above the surface and below 18,000 feet MSL to fly odd thousands plus 500 feet on magnetic courses of 0 through 179 degrees, and even thousands plus 500 feet on 180 through 359 degrees.
Is the VFR cruising altitude based on magnetic heading or magnetic course?
Magnetic course. The AIM describes it as magnetic course (ground track). A wind correction changes your heading but not the altitudes you may use.
Do VFR cruising altitudes apply below 3,000 feet AGL?
No. 91.159 applies only in level cruising flight more than 3,000 feet above the surface. Below that, choose any altitude that meets the minimum safe altitudes, cloud clearances and airspace rules.
What is the highest VFR cruising altitude?
17,500 feet MSL on a magnetic course of 0 through 179 degrees and 16,500 feet MSL on 180 through 359 degrees. At 18,000 feet MSL you enter Class A airspace, where flights must operate under IFR.
What is the difference between VFR and IFR cruising altitudes?
VFR uses thousands plus 500 feet; IFR uses whole thousands. Below 18,000 feet MSL in uncontrolled airspace, IFR flights use odd thousands on 0 through 179 degrees magnetic and even thousands on 180 through 359 (91.179); in controlled airspace they fly the altitude ATC assigns.