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Understanding Calculation Methods in Job Cost and Billing

Learn how each Calculation Method works and which Rate Sheet fields are required for tools, equipment, or materials.

In ToolWatch, every Rate Sheet row is assigned a Calculation Method. This determines how charges are calculated for each tool, material, or piece of equipment when it is assigned to a job.

Selecting the correct Calculation Method is the first and most important step in setting up Job Cost and Billing — it controls which fields are required, which rates are calculated, and what optional charges or credits can be applied.


What You'll Learn

In this article, you’ll learn:

  1. What a Calculation Method is

  2. The differences between Assignment, Calendar, and Hourly Usage Methods

  3. When to use each method

  4. Which Rate Sheet fields are required or optional per method

  5. What happens after a Calculation Method is selected

  6. Which fields apply based on the Rate Sheet type (Tools & Equipment vs. Materials & Consumables)


1. What Is a Calculation Method?

A Calculation Method defines how ToolWatch will apply charges to an item when it is assigned to a project.

Once a Calculation Method is selected:

  • ToolWatch determines which fields are required

  • Charges are calculated using the logic specific to that method

  • The Base Value becomes locked, and future updates from the Model Record won’t apply automatically

🔒 You can change the Calculation Method later, but you cannot remove it or revert the row to blank.


2. Overview of Available Calculation Methods

Method

How Charges Are Calculated

Common Use

Assignment

A one-time flat charge applied each time the item is assigned, regardless of how long it is used

Low-cost tools, consumables

Calendar

Charges based on elapsed assignment time (rounded to Minutes, Hours, or Days); rates vary by day/week/month

Standard equipment, tools assigned for multiple days

Hourly Usage

Charges only when usage hours are logged in the Equipment Usage Log

High-value or operator-tracked tools


3. When to Use Each Method

🔹 Assignment Method

Use when:

  • You want a fixed, flat charge per assignment

  • The duration of use is irrelevant

  • Simplicity and predictability matter

Common for: tape measures, hammers, job boxes


🔹 Calendar Method

Use when:

  • Time-based charges matter (e.g., daily rental logic)

  • You need accurate cost based on assignment duration

  • You want tiered pricing (daily, weekly, monthly)

Common for: ladders, generators, compressors


🔹 Hourly Usage Method

Use when:

  • You record actual hours of use

  • Charges must reflect true operation time of a Uniquely tracked tool

  • Idle charges are desired for unused but assigned hours

Common for: forklifts, scissor lifts, tracked machinery


4. What Happens After You Select a Method

Once you choose a Calculation Method for a row:

  • The Base Value becomes locked (no longer updates from the Model Record)

  • New field columns may appear based on that method

  • You must complete all required fields for the row to calculate charges

  • ToolWatch prevents deletion of the method — only changes are allowed


5. Rate Sheet Columns by Calculation Method and Sheet Type

Use the tables below to determine which columns apply to each Calculation Method based on your Rate Sheet type.


🧰 Tools & Equipment Rate Sheet

Supports Assignment, Calendar, and Hourly Usage Methods

🔹 Legend:

✅ = Required  ◯ = Optional  — = Not Used

🟦 = Optional only for Unique ID tools

🟨 = Optional only for Quantity ID tools

Rate Sheet Column

Assignment

Calendar

Hourly Usage

Hourly Usage Rate

✅*

Daily Rate

Weekly Rate

Monthly Rate

Idle Rate

Maintenance Rate

🟦

Initial Charge

Return Credit

Minimum Charge

Maximum Charge

🟦

🟨

Maximum Job Charge

Loss Charge

Cost Code

GL Charge Account

GL Credit Account

✅ Required – Must be completed for the method to calculate

◯ Optional – Available for all tool types

🟦 Optional – Only applies to Unique ID tools

🟨 Optional – Only applies to Quantity ID tools

*Hourly Usage Rate is only used in Calendar Method when using Calendar (Minutes) or Calendar (Hours)


🧾 Materials & Consumables Rate Sheet

Supports Assignment Method only

Rate Sheet Column

Assignment Method Only

Initial Charge

✅ Required

Cost Code

◯ Optional

GL Charge Account

◯ Optional

GL Credit Account

◯ Optional

📌 Calendar and Hourly Usage Methods are not supported for Materials & Consumables.

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