SUBTRACTION (-)

Overview

The SUBTRACTION operator subtracts one input from another after aligning both inputs to their common dimensions. In other words, subtraction uses the intersection of the shared dimensions.

The result keeps the coarser level in each shared dimension. Dimensions that exist on only one side are aggregated away.

Use this operator to calculate differences between two nodes.

Syntax

'Node1' - 'Node2'

Example usage: 'Revenue' - 'OPEX'

Parameters

Parameter	Description	Type	Required
Node1	Minuend node, specified using the node name in single quotes (e.g.`'Revenue'`)	Node reference	Yes
Node2	Subtrahend node, specified using the node name in single quotes (e.g.`'OPEX'`)	Node reference	Yes

Output Shape

Aspect	Behavior
Dimensionality	Both inputs are aggregated to their common dimensions (the intersection of the shared dimensions). Per shared dimension, the coarser level is used. Dimensions that exist on only one side are aggregated away.
Level values	Non-matching level values are preserved in the result.
Row count	Equal or reduced, depending on how much aggregation is required before subtracting.

Watch Out

Subtraction uses the common dimensions (intersection), just like addition.
Dimensions that exist on only one side are aggregated away before subtracting.
When subtracting a constant such as 'Revenue' - 100, the node is aggregated first and the constant is then subtracted from the total.
We recommend storing costs as negative values where possible, so addition can be used consistently throughout the model.
Both sides must have the same unit, unless one side is a scalar value.

Examples

Subtracting nodes with matching dimensions

Input node: Revenue

Year	Value
2025	500
2026	600
2027	550

Input node: Cost

Year	Value
2025	300
2026	350
2027	400

Formula: 'Revenue' - 'Cost'

Year	-> SUBTRACTION Result
2025	500 - 300 = 200
2026	600 - 350 = 250
2027	550 - 400 = 150

Subtracting nodes with different level values

When level values do not overlap, subtraction preserves both values in the result. The value from the second input appears as negative.

Input node: A

Year	Value
2025	100

Input node: B

Year	Value
2026	40

Formula: 'A' - 'B'

Year	-> SUBTRACTION Result
2025	100
2026	-40

Subtracting nodes with different dimensionality

This example shows how subtraction aggregates Node B to the common dimensions before subtracting it from Node A.

Input node: Node A

Year	Value
2025	5
2026	10

Input node: Node B

Year	Product	Value
2025	A	2
2026	A	3
2026	B	4

Formula: 'Node A' - 'Node B'

Year	→ SUBTRACTION Result
2025	5-2 = 3
2026	10-(3+4) = 3

Related Functions

Function	When to use instead
ADDITION (+)	When you want to combine values across the same shared-level alignment logic but add them instead of subtracting them.
MULTIPLICATION (*)	When you want to multiply values instead of subtracting them.