Describe the division the way your source document already describes it, and check the result before you commit.
Where this is in the app
Dashboard → open the return → Assets tab → open the asset → Split asset → Allocation
New to splitting? Start at Split one asset into the pieces it really is.
The same split can be described three ways. The Allocation panel asks How do you want to divide it? and offers Percentage, Dollar amount, and Units.
Percentage
Every piece takes a percentage, including the original asset.
The percentages across all pieces must total 100%. Until they do, the screen says so and names the running total, reading "Percentages must total 100% (currently 110%)." The preview stays empty in the meantime, showing "Enter a valid allocation to see the penny-exact preview."
Use it when you know the proportions. 40% roof, 60% structure.
Dollar amount
Enter the cost of each new piece. The original asset's amount is read-only and balances automatically to whatever is left of its original cost.
If the new pieces add up to the asset's full cost or more, the screen refuses, naming both figures: "New pieces total $10,000.00, which leaves nothing for the original asset (cost $9,500.00). Reduce the new piece amounts."
Use it when the invoice itemizes and you would rather enter figures than compute shares.
Units
Enter Total units in this asset first, then the unit count for each new piece. The original keeps the remaining units, shown read-only.
Use it when the asset is a countable quantity. Six machines, two of which are leaving. It is the mode that matches how the purchase was actually described.
Naming the pieces
Every row has a description field, including the original asset. The original's row is pre-filled with its current description, so you can rename it as part of the same action. "3 school buses" minus one bus should not stay named "3 school buses".
Leave a description blank and it is filled in for you:
The original keeps its existing description.
A new piece is named
Original description (split 2/3), numbered across the whole split with the original counted as piece 1.
Worth filling in when the pieces are genuinely different things. "Roof" and "Building shell" will mean more next year than "Building (split 2/2)".
More than two pieces
Add piece adds a row. A split is not limited to two.
The limit is 20 pieces per split, counting the original. At 20 the button is disabled and the screen reads "Maximum of 20 pieces per split."
Every piece needs a share greater than zero. New pieces can be removed with the x on their row, as long as at least two pieces remain.
Check the preview before you confirm
The Allocation Preview panel updates as you type. It shows each piece's description, cost, prior depreciation, §179, and MACRS basis, with a Total (= pre-split) row underneath.
Three things worth a look:
The total row. It should match what the original held. You are confirming a computation rather than trusting one.
Prior depreciation. This is the figure that decides each piece's remaining life. It is the one worth a second's attention.
The descriptions. They are what you will read on a report.
The preview covers the headline figures, not every allocated field. Land value, salvage, units, and the per-book figures are allocated by the same shares but are not shown in the preview table.
Nothing is created until you click Split asset.
One set of shares drives every figure
The shares you enter are not applied to cost alone. A 30/70 split allocates cost 30/70, and prior depreciation, and §179, and the book figures, all by the same ratio.
There is no way to give a piece one share of cost and a different share of prior depreciation. If the pieces need unrelated figures, entering them as separate assets is the other route. Your firm's judgement determines which is appropriate.