C# Integer Division (How it Works for Developers)

In C#, when you divide two integers using the / operator, the result is also an integer—the fractional part is simply discarded. This is known as integer division. The quotient is computed, and the result is truncated toward zero.

Let’s say you're generating an inventory report using IronPDF, and you want to show how many boxes are needed to store a certain number of items:

using IronPdf;
int totalItems = 19;
int itemsPerBox = 4;
int boxesNeeded = totalItems / itemsPerBox; // Result: 4
string html = $"<h1>Inventory Summary</h1><p>Boxes Needed: {boxesNeeded}</p>";
var renderer = new ChromePdfRenderer();
var pdf = renderer.RenderHtmlAsPdf(html);
pdf.SaveAs("InventorySummary.pdf");

using IronPdf;
int totalItems = 19;
int itemsPerBox = 4;
int boxesNeeded = totalItems / itemsPerBox; // Result: 4
string html = $"<h1>Inventory Summary</h1><p>Boxes Needed: {boxesNeeded}</p>";
var renderer = new ChromePdfRenderer();
var pdf = renderer.RenderHtmlAsPdf(html);
pdf.SaveAs("InventorySummary.pdf");

Output

This integer arithmetic returns 4—but the real answer is 4.75. This means your PDF output is incorrect if you don't handle the math properly. C# automatically performs integer division when both operands are of int type—the fractional part is discarded. This happens due to an implicit cast not existing between integer and floating point types.

To generate an accurate PDF, you need to use floating point types like float or double. When at least one operand is a floating point number, C# returns a floating point value, preserving decimal places.

Here’s how to correct the invoice example:

using IronPdf;
int totalItems = 19;
int itemsPerBox = 4;
double boxesNeeded = (double)totalItems / itemsPerBox;
string html = $"<h1>Inventory Summary</h1><p>Exact Boxes Needed: {boxesNeeded:F2}</p>";
var renderer = new ChromePdfRenderer();
var pdf = renderer.RenderHtmlAsPdf(html);
pdf.SaveAs("output.pdf");

using IronPdf;
int totalItems = 19;
int itemsPerBox = 4;
double boxesNeeded = (double)totalItems / itemsPerBox;
string html = $"<h1>Inventory Summary</h1><p>Exact Boxes Needed: {boxesNeeded:F2}</p>";
var renderer = new ChromePdfRenderer();
var pdf = renderer.RenderHtmlAsPdf(html);
pdf.SaveAs("output.pdf");

Output

The cast from int to double forces floating point arithmetic, so your PDF shows 4.75—the correct result. If you're outputting scientific data, cost breakdowns, or averages, this makes all the difference. This is an example of explicitly converting from one data type to another to perform correct arithmetic operations.

The remainder operator (%) is another tool you'll often need when generating table-based PDFs using IronPDF—especially when determining how many items fit in a row or if an extra row is needed.

using IronPdf;
int pageCount = 13;
int columnsPerPage = 5;
int leftoverColumns = pageCount % columnsPerPage;
string html = $"<h1>Layout Report</h1><p>Extra columns on last page: {leftoverColumns}</p>";
var renderer = new ChromePdfRenderer();
var pdf = renderer.RenderHtmlAsPdf(html);
pdf.SaveAs("output.pdf");

using IronPdf;
int pageCount = 13;
int columnsPerPage = 5;
int leftoverColumns = pageCount % columnsPerPage;
string html = $"<h1>Layout Report</h1><p>Extra columns on last page: {leftoverColumns}</p>";
var renderer = new ChromePdfRenderer();
var pdf = renderer.RenderHtmlAsPdf(html);
pdf.SaveAs("output.pdf");

Output

This is especially useful when dynamically building layouts or grids in HTML before rendering them to PDF with IronPDF. The modulus operator helps you calculate the remainder of division, which controls layout decisions such as column spans or pagination.

Example: Per-Unit Price Calculation with Floating Point Division

using IronPdf;
double[] totals = { 400.0, 275.5, 189.9 };
int units = 5;
string html = "<h1>Per-Unit Prices</h1><ul>";
foreach (var total in totals)
{
    double pricePerUnit = total / units;
    html += $"<li>${pricePerUnit:F2} per unit</li>";
}
html += "</ul>";
var renderer = new ChromePdfRenderer();
var pdf = renderer.RenderHtmlAsPdf(html);
pdf.SaveAs("UnitPrices.pdf");

using IronPdf;
double[] totals = { 400.0, 275.5, 189.9 };
int units = 5;
string html = "<h1>Per-Unit Prices</h1><ul>";
foreach (var total in totals)
{
    double pricePerUnit = total / units;
    html += $"<li>${pricePerUnit:F2} per unit</li>";
}
html += "</ul>";
var renderer = new ChromePdfRenderer();
var pdf = renderer.RenderHtmlAsPdf(html);
pdf.SaveAs("UnitPrices.pdf");

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