Persistent Decimal Calculation Bug – Percentage Interpreted Incorrectly

[migma]

Hi everyone,

I’m struggling with a persistent issue in AppSheet that I’ve been unable to solve, even after multiple rebuilds and hours of testing.

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Context

I’m building a portfolio management app where each stakeholder owns a percentage of an asset. When a revenue-generating event (called a Race) occurs, a bot is triggered and is supposed to create a row in the Transaction table for each owner.

The Earnings are calculated by:

appsheet

CopierModifier

LOOKUP([Race_ID], “Race”, “Race_ID”, “Earn”) * [Percentage]

This seems straightforward… but something is going very wrong.

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Issue

Even though [Percentage] is defined as a Decimal (2 digits), AppSheet consistently multiplies by 5 instead of 0.05.

So I get:

• 2125 × 5 = 10625
  Instead of:

• 2125 × 0.05 = 106.25

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What I’ve already tried

Structure:

Tables:

1. Ownership

• Ownership_ID – key

• Owner_email – text

• Horse_ID – ref

• Percentage – set to Decimal, 2 digits, with values like 0.05, 0.10

• AdjustedPercentage (virtual) – multiple formulas tested

2. Race

• Race_ID – key

• Horse_ID – ref

• Earn – Decimal

3. Transaction

• Transaction_ID – key

• Ownership_ID – ref

• Race_ID – ref

• Owner_email – text

• Percentage – Decimal

• Earnings – Decimal (calculated)

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Automation setup

• A bot triggers when a new Race is added

• It runs an action Create transaction owner on all related Ownership rows

• That action uses Set these columns to populate Transaction, including:

  • Percentage = [_THISROW].[Percentage]

  • Earnings = LOOKUP(…) * [Percentage]

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Things I’ve tested (and ruled out):

• Changed column type to Decimal (no Enum, no Text)

• Used [_THISROW].[Percentage] to pass values

• Used LOOKUP(…) from Ownership directly

• Created virtual columns like AdjustedPercentage = NUMBER([Percentage]) / 100

• Tried SUBSTITUTE([Percentage], “,”, “.”)

• Changed locale (en-US, fr-CA) in:

  • AppSheet App settings

  • Table settings

  • Google Sheets

  • Browser

Still… the value 0.05 is treated as 5 when used inside an action to create a new row.

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Bonus symptoms:

• 0.10 sometimes behaves like 1 (i.e. Earn × 1 = full amount)

• Even with a clean setup and fresh test values, the issue persists

• The only way I’ve ever gotten the right value (106.25) is by hardcoding it

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What I’m looking for

A reliable way to:

• Use real Decimal percentages (like 0.05)

• Multiply them in an action without AppSheet interpreting 0.05 as 5

• Avoid clunky conversions or locale-dependent hacks

If anyone has faced this in a financial context — or if you’ve worked around AppSheet’s quirks with decimals in Set these columns actions — I’d love to learn from your solution.

I can share a stripped-down test app if that helps.

Thanks in advance
– Martin

[Steve]

LOOKUP([Race_ID], “Race”, “Race_ID”, “Earn”)

should be

LOOKUP([_THISROW].[Race_ID], “Race”, “Race_ID”, “Earn”).

[Steve]

I’m gonna bet the Earn column is of type Percent. If so, LOOKUP([Race_ID], “Race”, “Race_ID”, “Earn”) produces a Percent result. Multiplying a Percent value by a Decimal value converts the Decimal to Percent and produces a Percent result. The internal implementation of the Percent type involves some magical behavior that can produce unexpected results. The Percent type is best used only as a display type.

[migma]

Thanks for the suggestion! I had the same thought at first, but I can confirm the Earn column is already set to Decimal (not Percent).
I double-checked both the column type in the Race table and the value format — everything is properly configured.
Unfortunately, the issue still persists even with a clean Decimal-to-Decimal multiplication.

Still, I really appreciate your insight — it helped me rethink how AppSheet might silently coerce types depending on context. If you have any other ideas, I’m all ears!

Thanks again,
Martin

[Steve]

@migma

Unfortunately, the issue still persists even with a clean Decimal-to-Decimal multiplication.

Please post screenshots of this configuration.

[migma]

Hi, see my screenshots,

[migma]

Just to clarify:
It’s a bot that triggers when a new race is created.
This bot runs an action that writes one row into the Transaction table for each owner, based on data from the Ownership table.

The Race_ID is passed directly into the transaction, and I now use that to calculate Earnings with:

[Percentage] * LOOKUP([Race_ID], “Race”, “Race_ID”, “Earn”)
That part is finally working properly — thanks again for the help!