Surface Mount Technology vs Through-Hole: Which Is Better for Your PCB Assembly?
- Harshit Shah
- Nov 4
- 9 min read
Updated: 4 days ago
Electronics are everywhere: phones, vehicles, medical devices, LED lights, satellites—you name it. At the heart of these devices is the printed circuit board (PCB), and how components are placed on that board can make a real difference in how the final product performs.
Two of the most common methods used today are surface mount technology vs through-hole. While both are widely used, they serve different purposes and work better in various scenarios.
If you’ve ever compared SMT vs through-hole for your next project and found yourself going in circles, you’re not alone. On the one hand, SMT offers speed and compactness. On the other hand, THT provides durability and mechanical strength.
Let's break down how these two technologies differ and which one is more likely to serve your goals.
Key Takeaways
Surface mount technology (SMT) places components directly on the PCB surface, making it ideal for compact, high-speed, and automated production.
Through-hole technology (THT) uses drilled holes for mounting, offering stronger mechanical connections for high-stress or high-power environments.
SMT is typically more cost-effective for large-scale production, while THT may offer better durability in rugged or mission-critical applications.
Both methods can be used together on the same PCB to balance size, cost, and structural strength—commonly seen in automotive, lighting, and industrial applications.
SMT tends to reduce waste and energy usage, making it a more sustainable choice for short product cycles, while THT may extend product life, reducing e-waste in the long term.
Emerging trends such as miniaturization, automation, and hybrid assembly are reshaping how SMT and THT are used in modern electronics.
The right assembly method depends on your design priorities, application environment, and long-term performance goals.
Table of Contents
What is Surface Mount Technology (SMT)?
Surface mount technology allows components to be placed directly onto the surface of the PCB. There’s no need to drill holes. These components, often referred to as SMT mount parts, are tiny and efficient; perfect for devices where space is limited.
This method is often the go-to in consumer electronics, smart devices, and wearables. It's also common in lighting PCB assembly and automotive PCB assembly, where lightweight and compact designs are valued.
If you're wondering about surface mount meaning, think of it as a modern, faster way to pack more performance into smaller packages.
What is Through-Hole Technology (THT)?
Through-hole technology, also known as thru-hole mounting, involves inserting component leads through pre-drilled holes on the PCB and soldering them to pads on the opposite side.
This method creates a strong bond between the component and the board. It’s very popular in the aerospace system, defense, industrial systems, and power-heavy applications.
Components in this process are usually larger, and the resulting through-hole PCB can withstand more vibration and physical stress; something SMT assemblies are less likely to handle over time.
Pros of SMT and THT
SMT (Surface Mount Technology)
Components are smaller, which means more parts on the board
Highly compatible with automation, making it ideal for fast production
Well-suited for LED board assembly, smart devices, and compact electronics
Reduces the overall weight of the device
Likely to offer better signal speed due to shorter lead lengths
If you want to understand more about the pros of SMT, read our new blog on Top 10 Benefits of Surface Mount Technology (SMT)
THT (Through-Hole Technology)
Offers stronger mechanical bonding
Easier to test and modify in prototypes
Handles temperature and physical stress better
Often used in mission-critical systems where failure is unlikely to be acceptable
Cons of SMT and THT
SMT
Repairs can be tricky due to the small size
Less durable under continuous vibration
May not suit large connectors or heavy components
THT
Takes longer to assemble the circuit board
Less efficient in high-density layouts
THT assemblies are significantly larger, limiting use in compact designs
What are the Key Differences Between SMT vs THT?
Both methods place components on a PCB, but they do it in very different ways.
Interesting reads: PCB vs PCBA Explained – Key Differences You Should Know
What are the Cost Comparison Between SMT and THT
Let’s break down how SMT and THT compare when it comes to cost and production factors.
On the one hand, SMT cost is lower in most high-volume scenarios due to automation and efficiency. The average assembly costs range from $0.03 to $0.08 per joint , depending on board complexity and volume. On the other hand, THT assemblies offer more mechanical strength, with costs typically between $0.07 to $0.15 per joint, which may help reduce maintenance or failure-related costs in demanding conditions.
The final decision is less about price alone and more about overall value. In many cases, hybrid assemblies offer a practical and balanced solution.
You can also read: How Much Does PCB Assembly Cost? Breakdown & Tips to Reduce
Mixed/Hybrid Assembly: Combining SMT and THT for Better PCBs
In many real-world designs, it is unlikely that a single assembly method will address every need. Surface mount technology is excellent for saving space, lowering costs, and increasing manufacturing speed. Through-hole technology, on the other hand, offers durability and is more stable under physical stress.
By integrating both methods, hybrid PCB assembly creates room for flexibility. SMT can be used for the bulk of the board components, such as microcontrollers, resistors, capacitors, and ICs, while THT can be applied to power connectors, large inductors, or any component that may be exposed to motion, heat, or vibration.
Additionally, mixed assemblies allow design engineers to balance complexity with reliability. For example, an industrial control board may use surface-mount components for signal processing and through-hole parts for I/O terminals that require mechanical anchoring.
This dual approach is now common in industries like:
Automotive, where PCBs must fit into tight spaces but endure vibration
Lighting, where LED drivers need compact control circuitry but strong power connections
Industrial automation, where rugged boards power systems under constant operation
In the end, hybrid PCB assembly is not just a workaround. It is a deliberate strategy to optimise layout, cost, performance, and durability.
If you're looking for a hybrid assembly, book a free consultation today
What is the Environmental Impact of SMT and THT?
The environmental footprint of any PCB assembly method depends not only on the process itself but also on how long the final product remains functional in the field.
SMT generally results in less raw material waste. The components are smaller, there is no need for drilling, and the automated processes reduce error, scrap, and energy use per board. Additionally, smaller boards mean less packaging, lighter shipping weight, and lower material consumption across the supply chain.
THT, while requiring slightly more material per component, often delivers greater reliability in harsh environments. This durability can reduce the number of replacements or repairs needed over the lifespan of a product. In sectors like aerospace or defense, this long-lasting performance may actually reduce environmental impact over time.
Viewed from a broader perspective, SMT is likely more sustainable for short-cycle consumer electronics, while THT offers long-term benefits in applications where failure is unlikely to be tolerated.
What are the Emerging Trends of SMT and THT in PCB Assembly?
The electronics manufacturing landscape is evolving rapidly, and SMT and THT are evolving with it.
Miniaturization continues to push SMT into new areas such as wearable technology and implantable medical devices.
THT remains important in systems that face heat, vibration, or high current
Automation and AI are streamlining both assembly processes, leading to faster, more reliable output
Automated insertion machines for THT are becoming more common, helping to close the speed gap between SMT and THT
These trends are making SMT versus THT less of a debate and more of a tailored design decision. It is increasingly about what combination gives you the performance and efficiency you need.
Applications of Surface Mount and Through-Hole PCB Assembly
Understanding the role each method plays helps determine where they are most effective.
Where SMT Excels
Smartphones and tablets
LED lighting systems
Consumer electronics
Wi-Fi and Bluetooth-enabled devices
In these examples, surface-mount components support space-saving, fast production, and sleek product design.
Where THT Wins
Aerospace and defense electronics
Power supplies and transformers
Heavy industrial equipment
High-vibration machinery
These environments demand strong mechanical connections, making through-hole technology PCB solutions the more reliable option.
It is unlikely that one approach will meet all needs. This is why application context remains so important in PCB design & assembly.
Which is Better for your project: SMT or THT
On one hand, SMT gives you speed, precision, and compact design. It is likely the best fit for devices that prioritize size, appearance, or fast production cycles. On the other hand, THT delivers long-lasting reliability in demanding conditions. If your board will face heat, stress, or vibration, through-hole components are the more dependable option.
Many projects now benefit from a hybrid approach. Mixing SMT and THT lets you take advantage of automation and layout efficiency while reinforcing the areas that demand strength and stability. This balanced strategy is not only practical. It is increasingly becoming the standard.
Conclusion
The discussion around surface mount technology vs through hole is less about which one is superior and more about what your project demands.
SMT shines in fast, compact, and mass-produced electronics. THT provides strength and resilience in environments where performance over time matters most. And SMT and THT together? That’s where things get interesting.
At A2Z Electronics LLC, we understand both approaches, individually and together. If you’re working on your next project and want insights from engineers who’ve seen it all, we’re here for you.
Frequently Asked Questions
Q1. What is the main difference between Surface Mount Technology (SMT) and Through-Hole Technology (THT)?
The main difference lies in how components are placed on the PCB.**In surface mount technology, components are mounted directly onto the surface of the board. In through-hole technology, leads from components are inserted into drilled holes and soldered to the opposite side of the board. This makes SMT more compact and automation-friendly, while THT provides stronger mechanical connections.
Q2. Which is better: Surface Mount or Through-Hole Technology?
It depends on your application. SMT is better suited for compact, high-speed, and high-volume electronics like smartphones and LED devices. THT is more durable and often used in aerospace, defense, and automotive where mechanical stress is likely. Both have strengths depending on the environment and performance needs.
Q3. Can SMT and THT be used together on the same PCB?
Yes. Many modern designs use both SMT and THT on a single board. This hybrid approach allows engineers to combine the space-saving benefits of SMT with the durability of through-hole components for connectors, switches, or heavy parts.
Q4. Which technology is more cost-effective and durable?
SMT is typically more cost-effective for high-volume production due to automation and lower material use. THT, while slightly more expensive, is generally more durable in high-vibration or high-power environments. Each offers value depending on what matters more—speed or strength.
Q5. What are some of the benefits of using surface mount technology (SMT) over through-hole technology (THT) in electronic boards?
SMT allows for smaller component size, faster assembly, higher circuit density, and more efficient use of board space. It is widely used in consumer electronics where space and weight matter. It also supports full automation, which speeds up production and lowers labor costs.
Q6. Which assembly type offers better repairability?
Through-hole technology tends to be easier to inspect, remove, and replace manually, making it more repair-friendly. SMT components are smaller and often densely packed, which can make repairs more complex and require specialized tools.
Q7. Does SMT improve PCB performance?
In many cases, yes. SMT can improve signal speed and reduce resistance and inductance due to shorter lead lengths. It also enables higher component density, which allows for more advanced and compact board designs.
Q8. Is SMD soldering better than through-hole?
SMD soldering, used in surface-mount assembly, is better suited for speed, miniaturization, and automation. However, through-hole soldering is better when a strong physical connection is needed. The best method depends on what your board needs to withstand and how it will be used.
