IPC-2152

IPC-2152 - Determining Current-Carrying Capacity in Printed Board Design

Standard for Determining Current-Carrying Capacity in Printed Board Design

Maintained by Giorgi Gaprindashvili Published July 3, 2026 Updated July 19, 2026

The cross-section that sets it

A trace is copper width × thickness. That cross-sectional area sets both current capacity and resistance; an internal layer adds laminate above, so it traps heat.

Key facts

Full title: Standard for Determining Current-Carrying Capacity in Printed Board Design
Published by: IPC
Published: 2009 - the current dedicated standard for PCB current-carrying capacity
Replaces: The conductor-sizing charts of IPC-2221 (for current capacity)
Method: Empirical, based on testing of hundreds of board configurations
Accounts for: Copper weight, board thickness, plane proximity, laminate material and cooling environment (air or vacuum)
Result vs IPC-2221: Usually allows a narrower trace for the same current and temperature rise

What IPC-2152 is

IPC-2152 is the dedicated standard for determining current-carrying capacity in printed boards. Published in 2009, it replaced the decades-old conductor-sizing charts in IPC-2221 with data derived from testing hundreds of real board configurations.

Where IPC-2221 offers a single formula and two charts, IPC-2152 provides an extensive set of nomographs plus correction factors, giving a substantially more accurate answer for how wide a trace must be to carry a given current at an allowed temperature rise.

How it improves on IPC-2221

The key advance is that IPC-2152 models the board around the trace. It applies correction factors for copper weight, board thickness, proximity to copper planes, laminate material and the cooling environment, none of which the IPC-2221 formula considers.

Because it captures heat spreading realistically, it often permits a narrower trace than IPC-2221 for the same current. Its testing also showed that on boards with good thermal spreading, internal traces can carry nearly as much current as external ones, overturning the old assumption that internal traces always need to be far wider.

How the standard is structured

The document has two parts: a main section with baseline conductor-sizing charts for boards tested in still air and in vacuum, and an appendix of correction factors for the real-world variables above.

The practical workflow is to read a baseline cross-sectional area from the charts for your target current and temperature rise, then apply the correction factors for your specific copper weight, stackup and planes. That is exactly the chart-reading and factor work that IPC-2152 calculators automate.

Caveats worth knowing

The baseline data assumes traces spaced more than about one inch apart. Closely spaced high-current traces heat one another, so their real temperature is higher than an isolated-trace result; tightly packed traces should be treated conservatively or analysed together.

As with any standard method, IPC-2152 is a design aid, not a guarantee. For critical or high-current designs, confirm the result with thermal simulation or prototype testing. The related guide walks through when IPC-2152 is worth the extra rigour versus a quick IPC-2221 estimate.

What IPC-2152 accounts for beyond IPC-2221

IPC-2221's single formula ignores all of these; IPC-2152 adds them as correction factors, which is why it usually permits a narrower trace.
Factor	Effect on current-carrying capacity
Copper weight / thickness	More copper means more cross-section, so more current for a given width
Board thickness	Changes how heat spreads away from the trace
Plane proximity	Adjacent copper planes spread heat, allowing more current
Laminate material	Substrate thermal conductivity affects the temperature rise
Cooling environment	Baseline charts cover still air and vacuum; forced air improves it further

Tools that use this standard

PCB trace width calculator

Related standards

Standard	Relationship	What it means
IPC-2221	Replaces (for current capacity)	IPC-2152 replaced the conductor-sizing charts in IPC-2221; IPC-2221 still covers broader design topics such as electrical spacing and layout.
IPC-2221C (2023)	Referenced by	IPC-2221C explicitly defers current-carrying capacity to IPC-2152.
MIL-STD-275 (IPC-D-275)	Supersedes basis of	The 1950s single-trace test data behind the old IPC-2221 charts, which IPC-2152's modern testing replaced.

Frequently asked questions

What is IPC-2152?

IPC-2152 is the modern IPC standard 'Standard for Determining Current-Carrying Capacity in Printed Board Design', published in 2009. It defines how to size a PCB trace for a given current and temperature rise using data from extensive testing, and it replaced the older conductor-sizing charts in IPC-2221.

What is the difference between IPC-2152 and IPC-2221?

IPC-2221 uses a single conservative formula from 1950s single-trace data; IPC-2152 is built on modern testing of hundreds of board configurations and adds correction factors for copper weight, board thickness, plane proximity and material. For the same current, IPC-2152 usually allows a narrower trace. The related guide compares them in detail.

Does IPC-2152 always give a narrower trace?

Usually, but not always. IPC-2152 allows narrower traces mainly where nearby copper planes or good thermal spreading help dissipate heat. A board with little thermal spreading may not gain much, so the benefit depends on the layout.

What does IPC-2152 account for that IPC-2221 does not?

Copper weight, board thickness, proximity to copper planes, laminate material and the cooling environment (its baseline charts cover still air and vacuum). IPC-2221's single formula ignores all of these.

Why do IPC-2152 calculators warn about trace spacing?

The standard's baseline data assumes traces spaced more than about one inch apart. Closely spaced high-current traces heat each other, so their real temperature is higher than an isolated-trace calculation predicts; treat tightly packed traces conservatively or analyse them together.

Should I use IPC-2152 or IPC-2221 for my design?

For current-carrying capacity on modern or high-current boards, IPC-2152 is the more accurate choice; IPC-2221's formula is a fast conservative sanity check. Many designers size with IPC-2221 first, then verify power traces against IPC-2152. The related guide gives a full decision walk-through.

Is IPC-2152 the current standard for trace current?

Yes. Since 2009 it has been the dedicated standard for PCB current-carrying capacity, and IPC-2221C explicitly defers to it for that purpose. For final sizing of critical power traces, pair it with thermal simulation or testing.

Source: IPC (shop.ipc.org). An overview for design reference - verify against the current edition before relying on it for compliance.