New Feature: Add Make splits even functionality (rework - negative amount)

[ikevin127]

Explanation of Change

Rework of PR #73474 which was reverted due to regression issue #74381.

Add a Make splits even button into the split edit table that will set the amounts (or percentages in the Split by percentage view) to equal proportions of the original expense amount.

• The ‘Make splits even’ button will only be available during the initial split
• The 'Make splits even' button will not be available when editing splits to avoid adding more logic to start
• When an amount cannot be split evenly, we'll add the remainder to one of the expenses. Ex. a $1 expense, split 3 ways + Make splits even will result in two .33 splits and one .34 split

Fixed Issues

$ #72207
$ #74381 (regression)
PROPOSAL:

Tests

Even splits

1. Create an expense for $10.
2. Select 'Split' from the 'More' menu for the expense.
3. Tap 'Add split' to create a 3rd split.
4. Tap 'Add split' to create a 4th split.
5. Tap 'Make splits even'.
6. Verify the amounts of the split expenses are all $2.50.

Uneven splits

Case 1

1. Create an expense for $10.
2. Select 'Split' from the 'More' menu for the expense.
3. Tap 'Add split' to create a 3rd split.
4. Tap 'Make splits even'.
5. Verify the amounts of the split expenses are $3.33, $3.33, $3.34.

Case 2

1. Create an expense for $1.01.
2. Select 'Split' from the 'More' menu for the expense.
3. Tap 'Add split' to create a 3rd split.
4. Tap 'Make splits even'.
5. Verify the amounts of the split expenses are $0.33, $0.33, $0.35.

Case 3

1. Create an expense for $1001.
2. Select 'Split' from the 'More' menu for the expense.
3. Tap 'Add split' to create a 3rd split.
4. Tap 'Make splits even'.
5. Verify the amounts of the split expenses are $333.66, $333.66, $333.68.

[NEW] Negative amount splits (coming from #74381)

1. On a workspace chat, create an expense for -$10 (negative $10).
2. Select 'Split' from the 'More' menu for the expense.
3. Tap 'Add split' to create a 3rd split.
4. Tap 'Add split' to create a 4th split.
5. Tap 'Make splits even'.
6. Verify the amounts of the split expenses are all -$2.50 (negative $2.50) and split is completed successfully.

Editing splits

1. Create an expense for $10.
2. Select 'Split' from the 'More' menu for the expense.
3. Click 'Save'.
4. Open one of the splits and select 'Edit Split' from the 'More' menu for the expense.
5. Verify the 'Make splits even' button does not show.

• Verify that no errors appear in the JS console

Offline tests

1. Open a new split flow, add splits, tap “Make splits even” and verify amounts update immediately.
2. Tap Save; verify optimistic UI (pending indicators: splits grayed out).
3. Reconnect; verify splits persist and pending clears without errors.

QA Steps

Same as Tests.

• Verify that no errors appear in the JS console

PR Author Checklist

• I linked the correct issue in the ### Fixed Issues section above
• I wrote clear testing steps that cover the changes made in this PR
  • I added steps for local testing in the Tests section
  • I added steps for the expected offline behavior in the Offline steps section
  • I added steps for Staging and/or Production testing in the QA steps section
  • I added steps to cover failure scenarios (i.e. verify an input displays the correct error message if the entered data is not correct)
  • I turned off my network connection and tested it while offline to ensure it matches the expected behavior (i.e. verify the default avatar icon is displayed if app is offline)
  • I tested this PR with a High Traffic account against the staging or production API to ensure there are no regressions (e.g. long loading states that impact usability).
• I included screenshots or videos for tests on all platforms
• I ran the tests on all platforms & verified they passed on:
  • Android: Native
  • Android: mWeb Chrome
  • iOS: Native
  • iOS: mWeb Safari
  • MacOS: Chrome / Safari
  • MacOS: Desktop
• I verified there are no console errors (if there's a console error not related to the PR, report it or open an issue for it to be fixed)
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Screenshots/Videos

Android: HybridApp

android-hybrid.mp4

Android: mWeb Chrome

android-mweb.mp4

iOS: HybridApp

ios.mov

iOS: mWeb Safari

ios-mweb.MP4

MacOS: Chrome / Safari + Regression Fix

web.mov

Regression fix:

Screen.Recording.2025-11-05.at.22.33.27.mov

MacOS: Desktop

desktop.mov

[melvin-bot]

Hey, I noticed you changed src/languages/en.ts in a PR from a fork. For security reasons, translations are not generated automatically for PRs from forks.

If you want to automatically generate translations for other locales, an Expensify employee will have to:

1. Look at the code and make sure there are no malicious changes.
2. Run the Generate static translations GitHub workflow. If you have write access and the K2 extension, you can simply click: [this button]

Alternatively, if you are an external contributor, you can run the translation script locally with your own OpenAI API key. To learn more, try running:

npx ts-node ./scripts/generateTranslations.ts --help

Typically, you'd want to translate only what you changed by running npx ts-node ./scripts/generateTranslations.ts --compare-ref main

[melvin-bot]

@parasharrajat Please copy/paste the Reviewer Checklist from here into a new comment on this PR and complete it. If you have the K2 extension, you can simply click: [this button]

[ikevin127]

@parasharrajat The only change from the previous PR is addition of additional arguments to getAmount function used in evenlyDistributeSplitExpenseAmounts:

    // Use allowNegative=true and disableOppositeConversion=true to preserve original amount sign
    const total = getAmount(draftTransaction, undefined, undefined, true, true);

♻️ Adjusted PR description, added additional manual test in the tests section and unit tests to cover the regression fix.

[codecov]

Codecov Report

✅ Changes either increased or maintained existing code coverage, great job!

Files with missing lines	Coverage Δ
src/libs/IOUUtils.ts	62.85% <100.00%> (+1.85%)	⬆️
src/libs/actions/IOU.ts	64.49% <84.61%> (+0.35%)	⬆️
src/pages/iou/SplitExpensePage.tsx	0.00% <0.00%> (ø)
... and 8 files with indirect coverage changes

[parasharrajat]

I didn't know that we support negative values as well in amounts.

[parasharrajat]

Technically, the math is correct but numerically the values do not match with the postive amount split.

1. IF we split 23 into 3 parts, I get 7.66, 7.66 and 7.68.
2. When we split -23 into 2 parts, we get -7.67 -7.67 and -7.66.

I would expect these numbers to remain the same to make it easier for users to understand this without using Math.

[parasharrajat]

Lint issue.

[ikevin127]

✅ Used Math.ceil for negative amount to preserve user expectation (matching positive amount split)as opposed to mathematical corectness.

Adjusted tests and updated regression fix video to match the updated logic.

[parasharrajat]

Reviewer Checklist

• I have verified the author checklist is complete (all boxes are checked off).
• I verified the correct issue is linked in the ### Fixed Issues section above
• I verified testing steps are clear and they cover the changes made in this PR
  • I verified the steps for local testing are in the Tests section
  • I verified the steps for Staging and/or Production testing are in the QA steps section
  • I verified the steps cover any possible failure scenarios (i.e. verify an input displays the correct error message if the entered data is not correct)
  • I turned off my network connection and tested it while offline to ensure it matches the expected behavior (i.e. verify the default avatar icon is displayed if app is offline)
• I checked that screenshots or videos are included for tests on all platforms
• I included screenshots or videos for tests on all platforms
• I verified tests pass on all platforms & I tested again on:
  • Android: Native
  • Android: mWeb Chrome
  • iOS: Native
  • iOS: mWeb Safari
  • MacOS: Chrome / Safari
  • MacOS: Desktop
• If there are any errors in the console that are unrelated to this PR, I either fixed them (preferred) or linked to where I reported them in Slack
• I verified proper code patterns were followed (see Reviewing the code)
  • I verified that any callback methods that were added or modified are named for what the method does and never what callback they handle (i.e. toggleReport and not onIconClick).
  • I verified that the left part of a conditional rendering a React component is a boolean and NOT a string, e.g. myBool && <MyComponent />.
  • I verified that comments were added to code that is not self explanatory
  • I verified that any new or modified comments were clear, correct English, and explained "why" the code was doing something instead of only explaining "what" the code was doing.
  • I verified any copy / text shown in the product is localized by adding it to src/languages/* files and using the translation method
  • I verified all numbers, amounts, dates and phone numbers shown in the product are using the localization methods
  • I verified any copy / text that was added to the app is grammatically correct in English. It adheres to proper capitalization guidelines (note: only the first word of header/labels should be capitalized), and is approved by marketing by adding the Waiting for Copy label for a copy review on the original GH to get the correct copy.
  • I verified proper file naming conventions were followed for any new files or renamed files. All non-platform specific files are named after what they export and are not named "index.js". All platform-specific files are named for the platform the code supports as outlined in the README.
  • I verified the JSDocs style guidelines (in STYLE.md) were followed
• If a new code pattern is added I verified it was agreed to be used by multiple Expensify engineers
• I verified that this PR follows the guidelines as stated in the Review Guidelines
• I verified other components that can be impacted by these changes have been tested, and I retested again (i.e. if the PR modifies a shared library or component like Avatar, I verified the components using Avatar have been tested & I retested again)
• I verified all code is DRY (the PR doesn't include any logic written more than once, with the exception of tests)
• I verified any variables that can be defined as constants (ie. in CONST.js or at the top of the file that uses the constant) are defined as such
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  • The style can't be created with an existing StyleUtils function (i.e. StyleUtils.getBackgroundAndBorderStyle(theme.componentBG)
• If the PR modifies code that runs when editing or sending messages, I tested and verified there is no unexpected behavior for all supported markdown - URLs, single line code, code blocks, quotes, headings, bold, strikethrough, and italic.
• If the PR modifies a generic component, I tested and verified that those changes do not break usages of that component in the rest of the App (i.e. if a shared library or component like Avatar is modified, I verified that Avatar is working as expected in all cases)
• If the PR modifies a component related to any of the existing Storybook stories, I tested and verified all stories for that component are still working as expected.
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• If the PR modifies the form input styles:
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Screenshots

🔲 iOS / native

01.11.2025_19.12.00_REC.mp4

🔲 iOS / Safari

01.11.2025_19.14.17_REC.mp4

🔲 MacOS / Desktop

01.11.2025_19.21.15_REC.mp4

🔲 MacOS / Chrome

06.11.2025_16.48.48_REC.mp4

01.11.2025_18.55.31_REC.mp4

🔲 Android / Chrome

01.11.2025_19.22.48_REC.mp4

🔲 Android / native

01.11.2025_19.18.48_REC.mp4

🎀 👀 🎀 C+ reviewed

[heyjennahay]

No concerns with product change

[trjExpensify]

@lakchote do you want to review this?

[NikkiWines]

Sorry for the delay here. Couple of comments, overall looks good and thank you for adding tests

[ikevin127]

@NikkiWines @lakchote Addressed latest comments, ready for final review! 🟢

Note: Failing unit test is related to Codecov, unrelated to this PRs changes.

[NikkiWines]

LGTM 👍

[lakchote]

LGTM! Thanks @ikevin127

[OSBotify]

✋ This PR was not deployed to staging yet because QA is ongoing. It will be automatically deployed to staging after the next production release.

[OSBotify]

🚀 Deployed to staging by https://github.com/lakchote in version: 9.2.55-3 🚀

platform	result
🖥 desktop 🖥	success ✅
🕸 web 🕸	success ✅
🤖 android 🤖	success ✅
🍎 iOS 🍎	success ✅

[OSBotify]

🚀 Deployed to staging by https://github.com/lakchote in version: 9.2.57-0 🚀

platform	result
🖥 desktop 🖥	success ✅
🕸 web 🕸	success ✅
🤖 android 🤖	success ✅
🍎 iOS 🍎	success ✅

[OSBotify]

🚀 Deployed to production by https://github.com/cristipaval in version: 9.2.57-4 🚀

platform	result
🖥 desktop 🖥	success ✅
🕸 web 🕸	success ✅
🤖 android 🤖	success ✅
🍎 iOS 🍎	failure ❌