Paste a table or a paragraph and see whether the totals add up and the percentages reach 100%. Works with tables from Excel, Google Sheets, Markdown, and CSV.
This tool runs entirely in your browser. What you enter is never sent anywhere.Your input is never sent anywhere.
DetailsNo total row or percentage column found yet. The checker looks for a row whose first cell starts with Total, Subtotal, Grand total, or Sum, and for columns of percentages.
TIP
Percentages that were rounded one by one can miss 100% by a small amount. This checker accepts a gap of up to 0.5 percentage points, so look first at larger gaps and at totals that are clearly off.
Check Whether Table Totals and Percentages Add Up
A table can look right and still be wrong. Every number seems plausible, but the Total row does not equal the rows above it, or the percentages add up to 97% instead of 100%. Scanning by eye misses this, especially in long tables and in tables with decimals.
AI tools make the problem more common. A language model writes figures that sound reasonable, but it does not always add them correctly, so a total can be off even when the table looks polished.
Paste a table or a paragraph and this checker does the arithmetic for you. It compares each stated total with the calculated sum and shows the exact difference, so you can see which figure is wrong.
When to Verify Numbers Before You Share Them
Review an AI-written table or summary
Before you paste a chatbot's table into a report, check that its totals and percentage splits agree with the rows.
Check a report from another team
Confirm the Total column and the percentage split in a table you received before you quote it in your own work.
Proof a sales or budget sheet
Run a quarterly revenue or expense table through the checker to catch a total that was not updated after someone edited a line item.
Proofread a press release or memo
Paste a paragraph with dollar amounts and percentages, such as an earnings update, and compare the stated total with the amounts around it.
How to Verify a Table or a Paragraph
- Choose Table for a pasted table, or Text for a paragraph.
- Paste your content, or load one of the samples to see how the checker reads it.
- In Table mode, the checker finds total rows, a total column, and percentage columns, then lists each check as a match or a mismatch.
- In Text mode, review the detected numbers. Click a number to exclude it, or click its Total button to set which number is the stated total.
Note: The checks run in your browser, so pasted content stays on your device.
What the Checker Can and Can't Read
- Total rows are found by the first cell of each row. It must start with Total, Totals, Grand total, Subtotal, or Sum. A line item such as "Total revenue" in a profit and loss table is also treated as a total row.
- A percentage column is found by a % sign in most cells, or by a header containing %, percent, pct, share, ratio, proportion, or mix. Every percentage column is expected to reach 100%.
- For sums, a gap smaller than half a unit of the least precise number counts as a match. Whole-number tables must match exactly. Percentages are allowed a gap of up to 0.5 points.
- Dollar signs and commas are ignored. K, M, and B (and thousand, million, and billion) are converted. In tables, (1,200) is read as -1,200.
- In Text mode, every number counted as an amount is added up and compared with the stated total, and every percentage is added up and compared with 100%. Exclude any number that belongs to something else, such as a store count or a growth rate.
- Years, dates, times, ordinals, durations such as "3 years", and labels like Q3 are left out of Text mode automatically. You can add them back by clicking them.
Why Totals and Percentages Don't Match: Common Causes
The patterns the checker catches most often, and what usually causes them.
| What you see | Likely cause | What to check |
|---|---|---|
| The Total is not the sum of the rows above it | A line item was edited, but the total was not recalculated | Find the last row that changed and recalculate the total |
| Percentages add up to 99% or 101% | Each share was rounded on its own | A gap of a point or less is usually rounding. Larger gaps point to a problem in the source data |
| A row's Total column differs from the sum of its other columns | A column that should not be counted, such as a unit price or a note, was included in the row total | Decide which columns belong in the row total and recalculate |
| Each subtotal is right but the grand total is off | A subtotal block was left out or counted twice | Add the subtotals by hand and compare them with the grand total |
| The total is far larger or smaller than expected | Units were mixed, such as thousands and millions in the same column | Check the column header and convert every value to the same unit |
Why AI-Written Tables Need a Math Check
AI tools now draft many tables and reports. Here is why the arithmetic in them deserves a second look.
Plausible is not the same as correct
A table written by an AI tool often has figures that look natural and convincing, which makes errors harder to spot. Before you question any single number, check the arithmetic: do the rows add up to the total, and do the shares add up to 100%?
Wrong totals spread when numbers are reused
A wrong total that is copied into a slide, a chart, or another report carries the error with it. Checking before you copy figures elsewhere saves rework later.
Rounding differences versus real mistakes
Percentages that miss 100% by a small amount often come from rounding each share separately. A gap of several points, or a dollar total that clearly does not match, is more likely a calculation or copy error, so check those first.
Paragraphs need the same check as tables
Press releases and summaries often put amounts and percentages inside sentences. Those figures are harder to scan than a table, so letting a tool pull them out and add them up is the faster check.
Mistakes That Slip Through Unchecked Numbers
Pasting an AI-written table into a deck without checking it
You check how the table looks, paste it into a presentation, and a colleague later points out that the total does not match the rows. The slide has to be redone.
💡 See the solution▼
Publishing percentages that add up to more than 100%
Each share looks fine on its own, so nobody notices that the whole set adds up to 103% until the report is already public.
💡 See the solution▼
Leaving a block out of the grand total
In a table with several subtotals, one block is missing from the grand total, so the grand total is too low.
💡 See the solution▼
Adding up the numbers in a paragraph by hand
You copy amounts from a report into a calculator one at a time. It takes a while, and one of them gets skipped.
💡 See the solution▼
Questions About Totals, Rounding, and Formats
Q.Which table formats can I paste?
A. You can paste cells copied from Excel or Google Sheets, a Markdown table with | separators, or comma-separated CSV text. Quoted CSV fields such as "1,200" stay in one cell. The checker picks the separator on its own. If it finds none, it splits columns on runs of two or more spaces.
Q.How does the checker find a total that doesn't match?
A. It looks for rows whose first cell starts with Total, Totals, Grand total, Subtotal, or Sum. A subtotal is compared with the item rows since the previous total row. A total or grand total is compared with all the item rows above it (total rows are skipped), and, if the table has earlier total rows, also with the rows since the previous total row. If the table has a header row and a column headed Total or Sum, each row's value is compared with the sum of that row's other number columns, as long as there are at least two. Any mismatch is shown with the stated value, the calculated value, and the difference.
Q.How close do the numbers need to be to count as a match?
A. A sum matches when the gap is smaller than half a unit of the least precise number in that check. With whole numbers, the sums must match exactly. With one decimal place, a gap of 0.1 is flagged. Percentage columns are compared with 100% and allowed a gap of up to 0.5 percentage points to cover rounding.
Q.Can it tell when percentages don't add up to 100%?
A. Yes. A numeric column is treated as a percentage column when more than half of its cells contain a % sign (or the word percent), or when its header contains %, percent, pct, share, ratio, proportion, or mix. The checker adds up the column, leaves out total rows, and compares the result with 100%. Every percentage column is expected to reach 100%, so ignore the result for columns that hold growth rates or margins.
Q.How does Text mode work?
A. The checker pulls every number out of your text and shows each one as a chip. The last number that follows a word such as total, in all, altogether, combined, sum, or comes to is treated as the stated total. All other amounts are added up and compared with it. Numbers with a % sign are added up separately and compared with 100%. Years, dates, times, ordinals, and labels like Q3 are left out automatically. You can click any number to include or exclude it, or use its Total button to choose the stated total yourself.
Q.Does it handle dollar signs, K and M, or negative numbers in parentheses?
A. Currency symbols are ignored and thousands separators are read correctly. The suffixes K, M, and B (and the words thousand, million, and billion) are converted, so $1.2M is read as 1,200,000. In tables, a value written as (1,200) is read as negative 1,200. Amounts in different currencies are not converted, and numbers written as words, such as twelve, are not read.
Q.Is my table or text sent anywhere?
A. No. The checks run as JavaScript in your browser, so pasted content stays on your device. That makes the tool suitable for drafts and figures that are not public yet.
Q.Why do AI-written tables contain math errors?
A. A language model writes text that looks right, and it does not always do the arithmetic behind a total or a percentage split. A table can read well and still have a total that does not match its rows. Checking the sums afterward is a quick way to catch this.
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