DME / GPS Leg Holding Calculator
Distance-defined holds decoded: where the turns happen for DME vs GPS ('along-track') legs, and the leg-time those distances produce at your speed.
The classic gotcha: DME legs measure from the STATION (so the turn DME depends on which way outbound points), GPS along-track legs measure from the FIX. Same chart, two different arithmetic conventions.
Formula
⚠️ For flight planning and education only — verify with current charts, AFM and ATC clearances. Not for primary navigation.
Distance-defined holds decoded: where the turns happen for DME vs GPS ('along-track') legs, and the leg-time those distances produce at your speed.
About DME / GPS Leg Holding Calculator
Timed holds gave way to measured ones, and the measuring introduced a trap: DME legs count from the ground station — so the outbound turn point is fix-DME plus or minus the leg depending on geometry — while GPS holds count along-track distance from the fix itself. This calculator does both conventions' arithmetic for any charted hold, plus the leg time your ground speed produces, which the fuel and EFC math downstream still wants.
How to use DME / GPS Leg Holding Calculator
- 1Enter — sensible defaults are pre-filled so you see a worked result immediately.
- 2Read the live results: .
- 3Check the "With your numbers" line to see the formula DME legs: turn at fix-DME ± leg length (per outbound direction); GPS legs: ATD from the fix itself substituted step by step.
- 4Adjust inputs (or flip the unit toggle) until the scenario matches yours, then copy or share the result.
Why use DME / GPS Leg Holding Calculator?
- ✓Instant, free and private — every calculation runs in your browser, nothing is uploaded
- ✓Built on the published formula DME legs: turn at fix-DME ± leg length (per outbound direction); GPS legs: ATD from the fix itself with sources cited on the page
- ✓The classic gotcha: DME legs measure from the STATION (so the turn DME depends on which way outbound points), GPS along-track legs measure from the FIX. Same chart, two different arithmetic conventions.
- ✓Switch units, tweak any input and watch every result update live
Frequently asked questions
Why does the outbound direction change the DME turn point?+
Because the DME counts from the station, not the fix: holding at the 10-DME fix with 5-nm legs pointing away, the outbound end is at 15 DME; with legs pointing toward the station, it's at 5 DME. Same pattern length, opposite arithmetic — misremembering the direction flies you double-length legs straight out of protected airspace.
What is along-track distance (ATD) in GPS holds?+
Distance measured along your path from the holding fix — the natural fix-referenced convention DME couldn't offer. RNAV systems annunciate it directly; charted RNAV holds specify leg length the same way. The mental shift from station-referenced to fix-referenced distances is the entire difference, and mixing the conventions is the modern version of the classic DME error.
Are distance legs better than timed legs?+
Operationally, yes: no timing, automatic wind compensation (the distance is the distance regardless of ground speed), consistent containment. The trade is dependency — and the residual skill question of what leg TIME the distance produces, which still matters for fuel math and EFC negotiation. This tool bridges the two: distance legs in, minutes out.
Where do I find whether legs are timed or distance on the chart?+
The holding depiction's annotation: a leg length ('5 NM') means distance legs; absence means standard timed legs (1 or 1.5 min by altitude). Enroute charted holds, missed-approach holds and HILPTs each follow the same convention. When ATC issues an ad-hoc hold verbally, leg specification is part of the clearance — and absent, timed legs are the default.
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