IPC 2615 Standard Explained: PCB Dimensioning & Tolerancing Requirements

If you’ve ever had a PCB rejected because hole locations were “out of spec” or spent hours arguing with a fabricator about what your drawing actually means, you’re not alone. After 15 years in this industry, I’ve seen more dimensional disputes than I care to remember—and most of them could have been avoided with proper documentation.

That’s exactly why IPC 2615 exists. This standard is the definitive guide for communicating printed board dimensions and tolerances, and understanding it can save you from costly rejects, miscommunication, and manufacturing delays.

What is IPC 2615?

IPC 2615, titled “Printed Board Dimensions and Tolerances,” is an industry standard published by IPC (Association Connecting Electronics Industries) in July 2000. It replaced the older IPC-D-300G and provides a comprehensive framework for dimensioning and tolerancing electronic packaging as it relates to printed boards and assemblies.

The standard is derived from ASME Y14.5M-1994 (Geometric Dimensioning and Tolerancing) but adapted specifically for PCB applications. At 76 pages with over 100 illustrations, IPC 2615 covers everything from basic dimension notation to complex positional tolerancing scenarios.

Why Does IPC 2615 Matter?

Here’s the reality: many PCB drawings include a note stating they comply with ASME Y14.5, yet the actual drawings don’t follow the standard properly. When your documentation is ambiguous, you’re essentially gambling on whether the fabricator interprets your intent correctly.

IPC 2615 bridges this gap by translating general GD&T principles into PCB-specific applications. It ensures that designers, fabricators, and quality inspectors all speak the same language when it comes to board dimensions.

Key Concepts in IPC 2615

Understanding Geometric Dimensioning and Tolerancing for PCBs

Traditional plus/minus tolerancing creates square tolerance zones. If you specify a hole position as ±5 mils in X and Y, you’re defining a 10×10 mil square zone. The problem? Corner cases can cause rejection of perfectly functional parts.

IPC 2615 promotes positional tolerancing using circular tolerance zones. A ±5 mil positional tolerance creates a circular zone that’s actually more generous—providing approximately 57% more acceptable area than the equivalent square zone. I’ve personally had to reject boards that would have passed if we’d used proper GD&T callouts.

Critical Terms You Must Know

The Datum Reference Frame

One of the most important concepts in IPC 2615 is establishing datums properly. A datum reference frame consists of three mutually perpendicular planes that serve as the origin for all measurements.

For rectangular PCBs, you typically need three datums:

• Primary Datum (A): Usually the bottom surface of the board
• Secondary Datum (B): One edge of the board
• Tertiary Datum (C): An adjacent perpendicular edge

The precedence matters. Your primary datum constrains three degrees of freedom, the secondary constrains two more, and the tertiary locks the final degree of freedom. Get this wrong, and your tolerance analysis falls apart.

Tolerance Types Covered in IPC 2615

Positional Tolerance

This is the most commonly used geometric tolerance in PCB work. Positional tolerance defines how far a feature’s actual location can deviate from its true position.

Example: A hole pattern with ø0.15mm positional tolerance referenced to datums A, B, and C means each hole center must fall within a 0.15mm diameter cylinder perpendicular to datum A, located at the basic dimensions from datums B and C.

Profile Tolerance

Profile tolerances control the shape of board edges and contours. If your board has a complex outline or slots, profile tolerance specifies the allowable deviation from the perfect form.

Perpendicularity Tolerance

This controls how straight hole axes are relative to board surfaces. Excessive deviation from perpendicularity can cause problems during assembly, especially with connectors and press-fit components.

Form and Orientation Tolerances

IPC 2615 also addresses:

• Flatness: Alternative specification for bow and twist
• Angularity: Orientation of features relative to datums
• Circularity: For round board profiles
• Concentricity: Alignment of axes between features

Typical PCB Manufacturing Tolerances

While IPC 2615 tells you how to specify tolerances, you need to understand what’s actually achievable in manufacturing. Here are typical capabilities you can expect:

Pro tip: Always confirm tolerances with your fabricator before finalizing designs. Specifying ±0.001″ on plated holes sounds great until you realize it requires special handling and premium pricing.

How to Apply IPC 2615 in Your Designs

Step 1: Establish Your Datum Reference Frame

Before dimensioning anything, decide how your board will be measured and assembled. Choose datums based on:

• Functional requirements (how does the board mount?)
• Manufacturing practicality (can the fab shop access these surfaces?)
• Inspection feasibility (can QC measure from these references?)

Step 2: Identify Critical Features

Not every dimension needs tight control. Focus GD&T callouts on:

• Mounting holes (alignment with enclosure)
• Connector locations (mating requirements)
• Edge card dimensions (slot fit)
• Fiducial locations (assembly accuracy)

Step 3: Apply Appropriate Tolerances

Use the tolerance types that match your functional requirements:

Step 4: Document Clearly

Reference IPC 2615 on your drawing with a note like: “Interpret per IPC-2615” or “Dimensioning and tolerancing per IPC-2615.”

Understanding Material Condition Modifiers

Maximum Material Condition (MMC)

When you apply MMC to a hole tolerance, you’re saying the stated tolerance applies when the hole is at its smallest allowable size. As the hole gets larger (departs from MMC), bonus tolerance is added.

Practical example: A 1.00mm hole with ±0.05mm tolerance and ø0.10mm positional tolerance at MMC:

• At MMC (0.95mm hole): Position tolerance = 0.10mm
• At 1.00mm hole: Position tolerance = 0.10mm + 0.05mm = 0.15mm
• At LMC (1.05mm hole): Position tolerance = 0.10mm + 0.10mm = 0.20mm

This bonus tolerance reflects reality—a larger hole is more forgiving of positional error.

Least Material Condition (LMC)

LMC works opposite to MMC. Use it when you need to maintain minimum wall thickness or edge distance. The tolerance applies at the largest hole size (least material remaining).

Read more IPC Standards:

IPC Standards Explained: A Comprehensive Guide to PCB & Electronics Assembly Standards

IPC 2615 Standard Explained: PCB Dimensioning & Tolerancing Requirements

MIL-STD-2000A: Military Soldering Standards for Electronic Assemblies

MIL-STD-1686: ESD Control Program Requirements for Military Electronics

IPC 1791 Standard: Everything You Need to Know About Trusted PCB Certification

MIL-STD-883: Complete Guide to Microelectronics Test Methods

J-STD-048 Explained: Complete Guide to Product Discontinuance Notifications

MIL-STD-750: Semiconductor Device Test Methods Explained

MIL-STD-454: General Requirements for Military Electronic Equipment

IPC 9194: Complete Guide to SPC for PCB Assembly Manufacturing

MIL-STD-202: Electronic Component Testing Methods & Procedures

IPC 4110: Complete Guide to Cellulose Paper Specs for Printed Circuit Boards

Boundary Scan Testing (JTAG) in PCB Design: A Complete DFT Guide

Axiomtek IPC-950 Review: Specs, Features & Performance [2026 Guide]

MIL-PRF-55681: Military Ceramic Chip Capacitor Specification Guide

Common Mistakes to Avoid

Mistake 1: Forgetting to define datums Your positional tolerance is meaningless without proper datum references. “±0.003″ from where?” is a question you don’t want your fabricator asking. I’ve seen boards fail inspection simply because the drawing showed hole positions without referencing any datums—the inspector measured from one edge while the designer intended measurements from the opposite edge.

Mistake 2: Over-tolerancing Specifying tighter tolerances than necessary increases cost without improving functionality. Be realistic about what your application actually requires. A consumer electronics board rarely needs the same precision as aerospace hardware. Ask yourself: if this dimension varies by another 2 mils, will the product actually fail?

Mistake 3: Mixing tolerance systems Don’t mix traditional ± tolerancing with GD&T on the same features. Pick one approach and be consistent. When you have some holes called out with ±0.003″ and others with positional tolerances, you create confusion about which tolerance takes precedence.

Mistake 4: Ignoring material condition Defaulting to RFS when MMC would work can result in unnecessarily tight effective tolerances and rejected boards that would actually function fine. If your holes need to accept pins, MMC almost always makes sense—you’re saying “the hole just needs to fit the pin,” which is usually the actual requirement.

Mistake 5: Specifying tolerances your fabricator cannot achieve Before finalizing your design, verify that your tolerances are manufacturable. Calling out ±0.001″ on hole position might look good on paper, but if your fabricator’s standard capability is ±0.003″, you’re either paying premium prices or setting up for rejection.

Real-World Application Example

Let me walk through how I’d apply IPC 2615 principles to a typical PCB design scenario.

The situation: You’re designing a controller board that mounts in an aluminum enclosure using four M3 screws. The board has a 50-pin edge connector that must align with a slot in the enclosure.

Step 1: Identify datums For this board, I’d establish:

• Datum A: Bottom surface of the board (primary)
• Datum B: The edge opposite the connector (secondary)
• Datum C: One side edge perpendicular to B (tertiary)

Step 2: Define critical tolerances

The four mounting holes need positional tolerance relative to datums A, B, and C. Since they mate with fixed holes in the enclosure, I’d specify:

• Hole diameter: 3.2mm +0.1/-0 (oversized for M3)
• Positional tolerance: ø0.15mm @ MMC | A | B | C

The edge connector location relative to the mounting holes is critical for alignment with the enclosure slot. This calls for a profile tolerance on the board edge where the connector sits.

Step 3: Document on the drawing The fabrication drawing includes a clear datum reference frame diagram, feature control frames for each critical tolerance, and a note referencing IPC 2615.

This approach ensures that whether the board is made in Asia, Europe, or domestically, every fabricator interprets the requirements identically.

IPC 2615 and Related Standards

IPC 2615 doesn’t exist in isolation. It works alongside other standards in the IPC ecosystem:

Useful Resources

Official Standards (Purchase Required)

• IPC-2615 – Available from IPC at shop.ipc.org
• ASME Y14.5-2018 – From ASME at asme.org
• IPC-6012F – Latest rigid PCB performance specification

Free Resources

• IPC Standards Overview – ipc.org/standards
• GD&T Reference Guide – gdandtbasics.com
• PCB Design Guidelines – Most fabricators provide free DFM guides

Training

• IPC offers certification programs including CID (Certified Interconnect Designer)
• ASME provides GD&T certification (GDTP)
• Many CAD vendors include GD&T training modules

Frequently Asked Questions

What is the difference between IPC 2615 and ASME Y14.5?

ASME Y14.5 is the general geometric dimensioning and tolerancing standard applicable to all mechanical engineering disciplines—machined parts, castings, assemblies, and more. IPC 2615 takes those core concepts and adapts them specifically for printed circuit board applications.

Think of IPC 2615 as Y14.5 translated for PCB designers—it uses the same fundamental principles (datums, positional tolerance, material conditions) but addresses PCB-specific scenarios like land patterns, plated-through holes, fiducial marks, and flexible circuits. The symbology is identical, but IPC 2615 provides context and examples that make sense in our world of copper traces and solder mask.

Do I need to purchase IPC 2615 to design PCBs?

While not legally required, having access to IPC 2615 is highly recommended if you create fabrication drawings or need to resolve dimensional disputes. Many experienced engineers reference it regularly when questions arise about how to properly dimension complex features.

If your company produces boards professionally, the investment of approximately $100-150 from IPC’s webstore is worthwhile. The standard provides clarity that can prevent manufacturing disputes costing thousands of dollars. Many organizations include it as part of their engineering library alongside IPC-2221, IPC-6012, and other core standards.

For hobbyists or occasional designers, understanding the basic principles (which many resources explain for free) may suffice—but having the official standard provides authoritative answers when questions arise.

What tolerances should I specify for typical through-hole components?

For standard through-hole components like resistors, capacitors, and DIP packages, a positional tolerance of ø0.15mm to ø0.25mm (6-10 mils) referenced to proper datums is usually sufficient. This accommodates typical component lead variation and assembly equipment accuracy.

Mounting holes that interface with enclosures typically need tighter control—ø0.10mm to ø0.15mm (4-6 mils) is common for precision fit applications. Press-fit connectors may require even tighter tolerances depending on the manufacturer’s specifications.

Always verify tolerances against your assembly requirements (can your pick-and-place equipment handle this precision?) and confirm your fabricator can meet the specification economically. Specifying tolerances tighter than necessary just increases cost without improving functionality.

How does IPC 2615 handle flexible and rigid-flex boards?

IPC 2615 includes specific provisions for flexible circuits, recognizing that they present unique challenges not found in rigid boards. Flex circuits can bend, twist, and change shape—making traditional fixed datum concepts problematic.

The standard discusses multiple datum reference frames for rigid-flex applications where different rigid sections may need independent datum systems. Section 5.3.9 specifically addresses these scenarios with practical examples. For flex portions, the standard acknowledges that dimensions may need to specify the board condition (relaxed vs. restrained) when measured.

When designing rigid-flex boards, pay particular attention to how datums transfer across flex sections and whether your tolerances make sense when the board is in its installed (bent) configuration versus flat for inspection.

Can I use basic ± tolerancing instead of GD&T?

Yes, traditional plus/minus tolerancing is still widely used and perfectly acceptable for many applications. Not every board requires full GD&T treatment—simple rectangular boards with standard through-hole components often do fine with conventional tolerance blocks.

However, GD&T as described in IPC 2615 offers significant advantages:

• Larger effective tolerance zones: The circular zone from positional tolerance provides roughly 57% more acceptable area than an equivalent square zone from ± tolerancing
• Clearer datum establishment: No ambiguity about measurement origins
• Precise design intent communication: Feature control frames leave no room for misinterpretation
• Material condition benefits: MMC and LMC allow bonus tolerance that reflects real functional requirements

For critical assemblies, tight enclosure fits, or when disputes arise about whether a board meets specifications, GD&T provides unambiguous definitions that ± tolerancing simply cannot match. The investment in learning proper GD&T pays dividends when you’re defending your design decisions.

Conclusion

IPC 2615 may seem like dry reading, but it solves real problems that cost real money. Proper application of this standard eliminates ambiguity in your documentation, reduces manufacturing disputes, and ultimately improves yields.

Start with the basics: establish clear datums, apply positional tolerances to critical features, and reference the standard on your drawings. As you gain experience, incorporate material condition modifiers and more advanced concepts.

The goal isn’t to make your drawings more complicated—it’s to make them clearer. When everyone from the designer to the fabricator to the quality inspector interprets your dimensions the same way, good things happen.

Your next step? Review your current fabrication drawings. Are the datums clearly defined? Are critical features properly toleranced? If not, IPC 2615 shows you exactly how to fix that.