You pull a thick envelope out of the mailbox. Inside is a piece of paper from an oil and gas operator telling you that a new well is producing. Next to your name is a tiny, absurdly specific number—something like 0.00125489.

This is your division order decimal. That string of digits dictates exactly how much money you will receive for every barrel of oil and thousand cubic feet of gas that comes out of the ground.

Most mineral owners just look at the number, assume the oil company’s accounting department got it right, sign the document, and send it back. We see this all the time. But signing a division order blindly is a massive leap of faith. The operator is legally protected from double liability once you sign it, meaning if they underpay you, you might have a very hard time recovering that money later. We broke down how division orders work in a previous piece, but today we need to talk about the math.

You can verify this decimal yourself. You don’t need a petroleum engineering degree. You just need a basic calculator, a copy of your lease, and the public records from your state’s oil and gas commission.

Here is exactly how you reconstruct the math the operator used—and how to spot when they owe you more.

The Foundation: The Standard Unit Calculation

Before we get into the headache of horizontal wells, we need to establish your base math. Every :Net Revenue Interest calculation starts with three basic facts.

First, you need your Net Mineral Acres. This is the gross acreage of your tract multiplied by your fractional ownership. If you own 25% of the minerals under a 40-acre tract, you own 10 Net Mineral Acres.

Second, you need your royalty rate. You find this in the oil and gas lease you or your ancestors signed. Let’s say it is a 1/5 royalty (20% or 0.20).

Third, you need the size of the drilling unit. This is the pool of acreage the operator put together to drill the well. A standard unit for a modern well might be 640 acres.

The standard formula is straightforward, as outlined by OneValor’s decimal calculator:

(Net Mineral Acres ÷ Unit Acres) × Royalty Rate = Decimal Interest.

Let’s plug our numbers in.

(10 ÷ 640) × 0.20 = 0.00312500.

If this was a vertical well sitting right in the middle of a neat 640-acre square, you would be done. Your decimal would be 0.00312500. But the oilfield rarely looks like that anymore.

The Horizontal Complication

Most wells drilled today are horizontal. An operator drills down a mile or two, turns the drill bit 90 degrees, and drills horizontally through the shale for another two or three miles.

These laterals are so long that they frequently cross boundary lines. A single wellbore might start in one 640-acre unit, cross a property line, and finish in a completely different unit. The industry calls these cross-section wells or allocation wells.

When a well produces oil from two different units simultaneously, the operator has to decide how to split the money. As detailed by the Oilpatch Press, the standard method is to allocate production based on the length of the perforated wellbore.

If a well is 10,000 feet long, and 4,000 feet of that well are inside your unit, your unit gets 40% of the production. The unit next door gets the other 60%.

This is where the math on your check stub starts to look strange. The operator takes your base decimal (0.00312500) and multiplies it by your unit’s allocation percentage (40%).

0.00312500 × 0.40 = 0.00125000.

That is the number that should appear on your division order. But to know if that 40% allocation is actually correct, you have to find the hard evidence. You have to look at the map.

How to Find and Read the State Plat Maps

You cannot guess how many feet of pipe are under your land. You have to pull the “As-Drilled” plat map.

Operators are required to file these maps with the state regulatory agency—the Railroad Commission in Texas, the Corporation Commission in Oklahoma, the Oil and Gas Conservation Commission in Colorado, etc. These plats are drawn by professional surveyors after the well is completed.

According to the Mineral Rights Podcast guide to division orders, you need to gather two specific documents to verify your interest: the state well plat and the pooling or spacing order.

Here is your step-by-step process:

  1. Get the Unit Size: In Texas, look for the Designation of :Pooled Unit filed in the county deed records. In almost every other state, you look for the Pooling Order signed by the state’s regulatory agency. This document tells you the exact gross acres in the unit (often carried out to three decimal places, like 640.000 acres).
  2. Get the As-Drilled Plat: Go to your state’s oil and gas commission website. Search for your well by its API number (a unique 10- or 14-digit identifier). Open the well file and find the final plat map.
  3. Find the Perforations: Look closely at the map. You will see a solid line representing the wellbore. But pay attention to the “First Take Point” (where the perforations start) and the “Last Take Point” (where they end).
  4. Calculate the Total Lateral: Subtract the first take point from the last take point to get the total perforated length. Let’s say the total length is 6,958 feet.
  5. Calculate Your Unit’s Share: The map will show the boundary line between your unit and the adjacent unit. It will clearly label how many feet of the perforated lateral sit on your side of the line. Let’s say it is 1,742 feet.
  6. Do the Math: 1,742 feet ÷ 6,958 total feet = 25.0359%.

You then take your base decimal and multiply it by 25.0359%. If your math exactly matches the division order, you can sign it with confidence.

Why the Operator’s Math Might Be Wrong

You might be wondering how a multi-billion dollar oil company could get simple math wrong. They have supercomputers and entire floors of accountants.

They get it wrong because the input data relies on human interpretation.

Before an operator pays anyone, they hire an outside oil and gas attorney to write a Division Order Title Opinion. As explained by the Oil and Gas Lawyer Blog, this attorney reviews decades of county deed records, probate files, and old leases to figure out exactly who owns what.

This process is notoriously messy. A deed from 1942 might be poorly worded. A grandfather might have died without a will, leaving fractional shares to a dozen squabbling heirs. A non-participating royalty interest might have been carved out of your tract fifty years ago and forgotten.

Title attorneys are humans. They miss things. They misinterpret ambiguous contract language. Sometimes the landman simply failed to pull a specific deed from the courthouse basement.

If the title opinion is wrong, the division order is wrong. The operator is simply paying based on the attorney’s instructions. And Your Decimal Isn’t Sacred: The Dirty Mechanics of Amended Units details exactly how these numbers can shift under your feet over time without you ever receiving a phone call.

Partial Sales and “Inflated” Decimals

There is one more massive variable that catches families off guard.

Sometimes, the company sending you the division order doesn’t actually sell 100% of the oil and gas from the well. Energy companies frequently partner up. Company A might own 75% of the well, and Company B might own 25%. They each take their share of the physical oil and sell it to different buyers.

If Company B is the one sending you a division order, they are only paying you for their 25% share of the production.

To make their accounting systems work, they will mathematically inflate your decimal. They take your true decimal and divide it by their ownership percentage. If your true decimal is 0.00078282, and they only sell 25% of the gas, the decimal on their specific division order will say 0.00313128.

This isn’t them being generous. It is just an accounting mechanism. But it represents a massive red flag for you: If this company is only accounting for 25% of your royalty, who is paying the other 75%? You should be expecting another division order from a completely different company. If it never shows up, your money is sitting in a suspense account somewhere.

What to Do When the Numbers Don’t Match

So you ran the numbers. You pulled the state plat map, you calculated your lateral length, you checked your lease royalty, and your decimal is 0.0045.

The division order says 0.0031.

Do not sign it. Pick up the phone and call the number on the letterhead. Ask to speak to the :division order analyst assigned to that well.

Be polite but firm. Tell them your math doesn’t match theirs. Ask them to send you their decimal calculation worksheet. According to Pheasant Energy, the operator uses these division orders purely to protect themselves from double liability. They want this resolved just as much as you do so they can release the funds.

If they refuse to show you the math, or if they send it and you see they gave away half your minerals to a cousin you’ve never heard of, you have a title dispute. You will likely need to provide the operator with a curative document—like a recorded deed or an affidavit of heirship—to prove their title attorney made a mistake.

Knowing What You Own

Sorting through plat maps and doing fractional math is frustrating. We completely understand why a lot of families just throw their hands up and accept the checks as they arrive. Mineral ownership is incredibly opaque by design.

But taking an afternoon to verify your decimals changes your relationship with your assets. You move from being a passive recipient to an active manager.

This kind of clarity gives you options. Whether you intend to hold these minerals for the next generation or you are eventually going to need to liquidate them to fund a retirement or handle an estate issue, you can’t make a good decision without knowing exactly what you own. You can’t value an asset if you don’t know the exact percentage of the revenue it commands.

Getting your hands dirty with the math is often the first step to real peace of mind. And if you run the numbers and realize your assets are far more complex than you thought, it is always worth a conversation to at least know your options.

:net-revenue-interest

Your Net Revenue Interest (NRI) is your final, exact slice of the pie. It is the percentage of total production revenue from a well that goes into your bank account, calculated after factoring in your unit acreage, your lease royalty rate, and any allocations for horizontal wellbores.

:pooled-unit

A pooled unit is a specific geographic boundary created by an oil and gas operator to drill a well. Because modern wells require hundreds of acres, operators combine (or “pool”) dozens of smaller individual land tracts together into one single block. Everyone inside that block shares in the production based on how much acreage they contributed.

:division-order-analyst

A division order analyst is the professional inside the oil and gas company responsible for maintaining the “pay deck”—the list of who gets paid what. They don’t decide who owns the minerals (the title attorneys do that), but they are the ones who process the paperwork, update addresses, handle death certificates, and answer your phone calls when your math doesn’t match theirs.