Directional Survey
Directional-survey maths — dogleg severity by the minimum-curvature method, the TVD/north/east step between two stations, and build-rate radius. Degrees in, field (per 100 ft) or metric (per 30 m). Fully offline.
Open Directional Survey →What is the directional survey calculator?
A directional-drilling survey calculator that runs entirely in your browser. It uses the minimum-curvature method — the industry standard — to work out the dogleg severity (DLS) between two survey stations, the true-vertical-depth, northing and easting step that separates them, and the radius of curvature that a given build or turn rate implies. Inclination and azimuth are entered in degrees; the trigonometry is done in radians internally. Field units report DLS per 100 ft and lengths in feet, while metric units report DLS per 30 m and lengths in metres. Every result updates as you type, nothing is uploaded, and the last inputs stay on your device so the tool works on a rig laptop with no signal.
How to use Directional Survey
- Choose your units — Use the Field / Metric switch at the top. Field normalises dogleg severity per 100 ft; metric normalises per 30 m.
- Pick a calculation — Select a tab — Dogleg severity, Station step or Radius — for the value you need.
- Enter the survey angles — Type the inclination and azimuth of both stations in degrees, plus the course length along the hole between them.
- Read the result — The main figure is your answer; the smaller line shows a helpful equivalent such as the total dogleg angle over the course.
Frequently asked questions
Which method does it use?
The minimum-curvature method, which fits a circular arc between two stations. It is the accepted standard for wellpath survey calculations and is more accurate than the radius-of-curvature or tangential methods.
What happens when both stations are identical?
The dogleg is reported as zero rather than an error. When the two inclination and azimuth pairs match, there is no curvature, and the ratio factor used for the step falls back to one.
How is dogleg severity normalised?
The raw dogleg angle over the course length is scaled to a standard interval — 100 ft in field units or 30 m in metric — so wells can be compared on a like-for-like basis.
Does it work offline?
Yes. There are no dependencies and no network calls, so it runs with no signal, and your last inputs are saved on your device.
Tips
- Azimuths are measured clockwise from north; enter them as bearings from 0 to 360 degrees for correct northing and easting.
- Course length is the measured-depth interval between the two stations, along the hole, not the vertical difference.
- Radius of curvature falls as build rate rises — a gentle build rate gives a long, sweeping arc, so plan clearance accordingly.