Overlap is the cost you are already paying
Every pass you drive by eye, you overlap the last one a little so you do not leave a strip. That overlap is seed, fertilizer, chemical and fuel put down twice, and time spent covering ground you already covered. Auto steer on RTK takes the overlap to about an inch. Here is what the studies measured, what the math looks like at your implement width, and how to figure your own number. Percentages and acres; you know your prices.
Ask us to run your numbers Call or Text (580) 394-0089What the studies measured
Nobody has to take our word for the hand-steering number; it has been measured a lot.
- North Dakota State University's extension economists put hand-steered overlap at about 10 percent for planters, fertilizer applicators and sprayers, falling to 0.5 percent with guidance, and note that on fields with potholes, waterways and point rows overlap can add up to 15 percent more inputs. (NDSU Extension)
- University of Georgia extension measured operators using foam markers overlapping about 5 percent of the width on every pass, and lightbars cutting that to under 3 percent without adding skips. (UGA Extension)
- University of Wisconsin watched mowers in the field and found overlap from 0.5 to 16 percent, averaging about 5 percent, and machines on auto steer cutting it in half. (UW-Madison IPCM)
- USDA Agricultural Research Service measured guidance cutting overlaps by up to 6 percent of field area and skips by up to 16 percent on fertilizer and herbicide passes, and found new operators overlap about 20 percent more than operators with six or more years in the seat. (USDA ARS, Kharel et al. 2022)
- A three-year side-by-side on small, irregular fields in Finland found auto steer cut overlap and wasted movement by 21 percent, total field time by about 10 percent and fuel per acre by about 20 percent. Big square fields will see less; small odd ones more. (Estonian University of Life Sciences, 2025)
The math at your implement width
Overlap as a share of your inputs is just the overlap width divided by the implement width. Here is what that comes to.
| Implement width | 1 inch (RTK auto steer) | 6 inches (good operator, daylight) | 1 foot (typical) | 2 feet (night, odd field) |
|---|---|---|---|---|
| 30 ft drill or planter | 0.3% | 1.7% | 3.3% | 6.7% |
| 40 ft drill or planter | 0.2% | 1.2% | 2.5% | 5.0% |
| 60 ft drill or air seeder | 0.1% | 0.8% | 1.7% | 3.3% |
| 90 ft boom | 0.1% | 0.6% | 1.1% | 2.2% |
| 120 ft boom | 0.1% | 0.4% | 0.8% | 1.7% |
To turn a percentage into acres, multiply by your acres. One foot of overlap on a 40-foot drill across 2,000 acres is 50 acres seeded and fertilized twice. On RTK it is about 4. One foot on a 90-foot boom across 5,000 sprayed acres is 55 acres sprayed twice, every application; on RTK it is about 5.
Those same overlapped acres are also driven acres: the extra passes, the hours, the fuel and the wear are the same percentage. On a 2,000-acre drill at one foot of overlap you drive roughly 50 acres' worth of extra passes per seeding.
The other half: skips
The reason people overlap by hand is fear of the skip. A skip in the drill is a strip of bare dirt that is a weed strip by June. A skip in the spray pass is the weeds that got away, and the second trip to get them. NDSU and USDA both found guidance cuts skips at the same time it cuts overlap, because you no longer have to err one way or the other. On the coverage map you can see a skip before you leave the field. On an ISOBUS kit the boom sections shut themselves off over painted ground, so the headland and the point rows stop being double-sprayed too.
What it does and does not change
Auto steer changes how much of the field gets covered twice. It does not fix a bad A-B line or a boom that is not the width the screen thinks it is. Rate and population are a separate job: the FJD system sends GPS and speed to the rate controller or planter monitor you already run, or we offer rate and section controllers that work on the same display. And the savings on a square 160 with no obstacles are smaller than on a quarter with a creek, three terraces and a pivot; the studies that measured the biggest savings were on small, irregular fields.
How to figure your own number
- Pick the implement you run the most acres with and its width.
- Be honest about your overlap by hand. Measure it: at the end of a pass, step off from the edge of this pass to the edge of the last one. Daylight with a marker is usually six inches to a foot; at night, more.
- Divide by the width. That is the percentage of seed, fertilizer, chemical, fuel and hours you are putting down twice.
- Multiply by your acres for that implement. Those are your double acres per season.
- Subtract the RTK number: about an inch, so roughly a tenth to a third of a percent.
Or send us the implement widths and acres and we will do it for you.
- Your main implements and their widths
- Acres you cover with each per season
- Whether you plant on last year's rows or run the same tracks
- Whether you have RTK now, and from whom
Common questions
Is the savings only on inputs?
No. Overlapped acres are driven acres, so the same percentage comes off hours and fuel, and off wear on the drill and the tractor. A three-year Finnish field study measured about 10 percent less field time and about 20 percent less fuel per acre on small irregular fields. Big square fields will be lower.
Do I need RTK for this, or does WAAS get me most of it?
WAAS drifts a few inches to half a foot through the day, so you still set a few inches of overlap to be safe. That is better than by hand but not the one-inch number. RTK is what takes overlap to about an inch and keeps it there.
What about the headlands and point rows?
That is where the biggest double-coverage usually is, and steering alone does not fix it. ISOBUS section control on the AT2, AT2 Max or AT2 Ultra shuts boom sections or planter sections off over ground that is already painted. On the drill side, the coverage map at least shows you where you doubled.
My fields are big and square. Does any of this matter?
Less. A foot of overlap on a 120-foot boom is under 1 percent. Where it still matters on a big square field is skips, night work and repeatability: planting on last year's rows and spraying between them.
Where does the "about an inch" come from?
RTK correction from a base station you own or from the GEODNET network over cellular. Our guide on what RTK costs to run covers the options and which ones have no network fee.
More on auto steer
All buyer guides · Autosteer for Tractors · Is my tractor steer-ready? · Older tractors · Articulated 4WDs · Combines · Sprayers · Swathers · RTK vs WAAS · What RTK costs to run · FJD AT2 vs Wheelman · FJD AT2 · AT2 Max · AS2 steer-ready · AH2 hydraulic · GEODNET RTK · John Deere · Case IH · New Holland · Kubota · Massey Ferguson · Reviews
Published 10/16/2026 by Deep Sand Tech. Written from our own installs and support calls on farms across the US, not from a brochure.