---
title: "Beam Load Calculator"
description: "How much load can a wood beam carry? Max distributed and point loads for C16-D40 timber, bending + deflection checked. Free."
image: "https://nestingcalc.com/og-default.png"
url: "https://nestingcalc.com/beam-load-calculator/"
locale: "en"
---

# Beam Load Calculator

How much load can a wood beam carry? Max distributed and point loads for C16-D40 timber, bending + deflection checked. Free.

Enter the span, the beam's width and height and the timber grade, and get the maximum allowable load as a planning estimate. The calculator checks bending (design strength fmd = kmod x fmk / yM with kmod = 0.8 and yM = 1.3, EN 338 grades) and deflection (limit L/300) and reports whichever governs - in kg/m and kN/m, or kg and kN for a center point load. The self-weight of the beam itself is subtracted automatically.

Interactive calculator (open in browser): [https://nestingcalc.com/beam-load-calculator/](https://nestingcalc.com/beam-load-calculator/)

## FAQ

How much weight can a wooden beam carry?

It depends on span, section and grade. A C24 50 x 200 mm joist over a 4 m span carries roughly 1.4 kN/m (about 140 kg/m) before the L/300 deflection limit is reached, while the same section over 2 m carries several times more, because capacity falls with the square of the span. Shorten the span or deepen the beam and the allowable load rises fast.

What does grade C24 mean?

C24 is a European strength class (EN 338) for softwood with a characteristic bending strength of 24 N/mm2. The number after the letter is the strength, so C30 and C40 are stronger. D-grades (D24-D40) are hardwoods - denser and heavier for the same strength number.

What size beam do I need for a 4 meter span?

For a typical residential floor load around 2 kN/m including self-weight, a C24 joist of 75 x 235 mm or two 50 x 200 mm side by side are common starting points. Use the calculator to test your exact section: increase the height before the width, because the section modulus grows with the square of the height.

Why is a beam stronger on edge than flat?

Section modulus is W = b x h2/6. Laying a 50 x 200 beam flat swaps the two dimensions, so W drops from about 333,000 mm3 to 20,800 mm3 - a 16-fold loss. That is why joists and rafters always stand on edge.

Is this a structural calculation?

No - it is a planning estimate. The tool applies Eurocode-style factors (kmod = 0.8, yM = 1.3) and an L/300 deflection limit, but ignores shear, bearing, lateral buckling, notches, holes and load duration. Anything you build to must be verified by a structural engineer against your local building code.

## Related calculators

-   [Lumber Weight Calculator (kg/m³)](https://nestingcalc.com/lumber-weight-calculator/)

    Weight of any board by species and size, dry or green — density table for 18 species included. Free.

-   [Linear Cutting Calculator](https://nestingcalc.com/linear-cutting-calculator/)

    Optimize cuts for bars, pipes and profiles — minimize waste, free.

-   [Board Feet Calculator](https://nestingcalc.com/board-feet-calculator/)

    Calculate board feet, total volume and lumber cost for any board — free.

## Related guides

-   [Steel Weight Table: kg/m for Round Bar, Tube, Flat Bar and Pipe](https://nestingcalc.com/guides/steel-weight-table/)

    Weight per metre of steel round bar 6-100 mm, square hollow sections, flat bar and pipe - with the formula kg/m = 0.00785 x area in mm2 and worked examples.

```json
[{"@context":"https://schema.org","@type":"Organization","@id":"https://nestingcalc.com/#organization","name":"NestingCalc","url":"https://nestingcalc.com/","description":"Free cutting optimizer & nesting calculators","logo":"https://nestingcalc.com/logo-512.png"},{"@context":"https://schema.org","@type":"WebSite","@id":"https://nestingcalc.com/#website","name":"NestingCalc","url":"https://nestingcalc.com/","inLanguage":"en","publisher":{"@id":"https://nestingcalc.com/#organization"}},{"@context":"https://schema.org","@type":"BreadcrumbList","itemListElement":[{"@type":"ListItem","position":1,"name":"NestingCalc","item":"https://nestingcalc.com/"},{"@type":"ListItem","position":2,"name":"Beam Load Calculator","item":"https://nestingcalc.com/beam-load-calculator/"}]}]
[{"@context":"https://schema.org","@type":"WebApplication","@id":"https://nestingcalc.com/beam-load-calculator/#webapp","name":"Beam Load Calculator — NestingCalc","url":"https://nestingcalc.com/beam-load-calculator/","applicationCategory":"DesignApplication","operatingSystem":"Web","offers":{"@type":"Offer","price":"0","priceCurrency":"USD"},"publisher":{"@id":"https://nestingcalc.com/#organization"}}]
```