Automotive Fuse Search & Color Lookup
Rating
Type
The selected combination of current rating and blade size is not standard. Please verify against standard charts.
LOOKUP RESULTS
Input Parameters Specification
Current Rating (Amps)The safe maximum continuous current limit the fuse conductor element can handle before melting to break the circuit pathway.
Conductor Blade SizeDefines the physical casing standard of the plug-in fuse package, ranging from micro units to heavy-duty Maxi boxes.
Jacket Group CodeIdentifies standard manufacturer group codes, such as APT, ATM, ATC, or APX, ensuring exact component replacement.
Fuse DimensionsSpecifies length, width, and height boundaries of the active socket, preventing mechanical insertion mismatching.
Practical Operational Examples
Radio & Console Feeds
In-cabin dashboard radios commonly use a 10 Amp mini fuse. Matching this current to the regular size yields a red housing.
Headlamp High Beams
Car headlamp assemblies utilize a 15 Amp regular blade fuse. Under standard color maps, this is identified by a blue jacket.
Alternator Battery Lines
Heavy charging circuits running to the alternator utilize Maxi fuses, often colored green (30A) or orange (40A) to protect high-current loads.
Low Profile Retrofits
Japanese import models utilize low-profile LP-mini fuses to save engine bay terminal space, requiring compact physical dimensions.
Formulas & Mathematical Logic
Automotive fuses protect vehicle wiring through the principles of Joule heating, where current flow creates thermal rise.
Core thermal equation: Power Loss = I × I × R (Resistance)
Conductor breakdown: Melting threshold is reached when Power Loss > Ambient Heat Dissipation
Because higher-rated fuses must carry more current, their internal metal element is made thicker, which reduces resistance and prevents early thermal breakdown.
How to Use This Calculator
Select the desired current rating in Amps from the dropdown menu.
Choose the target physical blade housing size (e.g., Mini, Regular, or Maxi).
Click the orange Calculate button to instantly populate color codes and dimensions.
Check the live result card to see the exact matching housing color.
Use the dimension metrics and group codes to verify a secure socket replacement.
About This Calculator
Instantly verify automotive blade fuse color codes and dimensions.
The CalcBoy Automotive Fuse Color Lookup Tool maps vehicle terminal current limits against standard plug physical designs.
Automotive fuses are safety components designed to protect vehicle wiring systems from high-current shorts and electrical overloads. If too much current flows through a wire, it can overheat, melt the wiring insulation, and damage expensive electronic modules like the ECU. To prevent this, a fuse acts as a weak link, safely melting its internal conductor to open the circuit before damage can occur.
Car manufacturers follow standard color coding conventions (such as ISO 8820) so mechanics and vehicle owners can easily identify fuse ratings by their plastic housing color. This tool matches specific current ratings and casing formats to find the standard color, physical group, and dimensions quickly.
Always consult your vehicle owner's manual before making replacements. Always replace a blown fuse with one of the exact same ampere rating; using a higher-rated fuse can bypass circuit protection and create serious fire hazards.
Main BenefitSpeeds up the identification of blown fuses and safe current limits.
Blade StylesSupports Micro2, Micro3, LP-Mini, Mini, ATO/Regular, and Maxi layouts.
ScopeCovers low-current sensor paths up to heavy-duty main battery feeds.
Safety LimitNever replace a fuse with one of a higher rating to avoid circuit fires.
Note: If a newly replaced fuse blows immediately after insertion, there is an active short circuit in the system that must be resolved before proceeding.
Standard Blade Fuse Dimensions
This table compares standard physical dimensions and group codes across standard vehicle fuse families.
| Blade Size |
Blade Group |
Dimensions (L × W × H) |
Max Current (Amps) |
| Micro2 |
APT, ATR |
9.1 × 3.8 × 15.3 mm |
5, 7.5, 10, 15, 20, 25, 30 |
| Micro3 |
ATL |
14.4 × 4.2 × 18.1 mm |
5, 7.5, 10, 15 |
| LP-Mini (Low Profile) |
APS, ATT |
10.9 × 3.81 × 8.73 mm |
2, 3, 4, 5, 7.5, 10, 15, 20, 25, 30 |
| Mini |
APM, ATM |
10.9 × 3.6 × 16.3 mm |
2, 3, 4, 5, 7.5, 10, 15, 20, 25, 30 |
| Regular |
APR, ATC, ATO, ATS |
19.1 × 5.1 × 18.5 mm |
0.5, 1, 2, 3, 4, 5, 7.5, 10, 15, 20, 25, 30, 35, 40 |
| Maxi |
APX |
29.2 × 8.5 × 34.3 mm |
20, 25, 30, 35, 40, 50, 60, 70, 80, 100, 120 |
Standard Automotive Fuse Color Codes
Reference guide mapping safe current limits to housing colors across vehicle system types.
| Current Rating |
Micro2 |
Micro3 |
LP Mini |
Mini |
Regular |
Maxi |
| 0.5 A | --- | --- | --- | --- | Dark Blue | --- |
| 1 A | --- | --- | --- | --- | Black | --- |
| 2 A | --- | --- | Grey | Grey | Grey | --- |
| 3 A | --- | --- | Violet | Violet | Violet | --- |
| 4 A | --- | --- | Pink | Pink | Pink | --- |
| 5 A | Tan | Tan | Tan | Tan | Tan | --- |
| 7.5 A | Brown | Brown | Brown | Brown | Brown | --- |
| 10 A | Red | Red | Red | Red | Red | --- |
| 15 A | Blue | Blue | Blue | Blue | Blue | Blue |
| 20 A | Yellow | --- | Yellow | Yellow | Yellow | Yellow |
| 25 A | Clear | --- | Clear | Clear | Clear | Grey |
| 30 A | Green | --- | Green | Green | Green | Green |
| 35 A | --- | --- | Bluegreen | Bluegreen | Bluegreen | Brown |
| 40 A | --- | --- | Orange | Orange | Orange | Orange |
| 50 A | --- | --- | --- | --- | --- | Red |
| 60 A | --- | --- | --- | --- | --- | Blue |
| 70 A | --- | --- | --- | --- | --- | Amber/Tan |
| 80 A | --- | --- | --- | --- | --- | Clear |
| 100 A | --- | --- | --- | --- | --- | Violet |
| 120 A | --- | --- | --- | --- | --- | Purple |
Frequently Asked Questions
1. Why do car fuses have distinct color codes?
Automotive fuses follow color conventions (such as ISO 8820) so mechanics and owners can quickly verify a fuse's Ampere limit visually without having to read small printed text on the fuse body.
2. Can I replace a blown fuse with one of a higher rating?
No. Replacing a blown fuse with a higher-amp rated one (e.g. replacing a 10A fuse with a 20A one) allows too much current to flow, which can melt vehicle wiring and start electrical fires.
3. What is the difference between ATO and ATC fuses?
ATO fuses are open on the bottom, allowing air exposure, whereas ATC fuses have a sealed plastic shell, which protects the internal fuse element from moisture and corrosion.
4. What happens if a new fuse blows immediately?
If a newly installed fuse blows immediately, there is an active short circuit or high overload in that circuit that must be diagnosed and repaired before inserting another fuse.
5. What is the difference between Mini and LP-Mini fuses?
Both fuses have the same width and thickness, but Low-Profile (LP) Mini fuses have shorter metal blades that do not extend beyond the plastic housing, saving vertical socket space.
6. Are fuse colors identical across Maxi and regular ATO sizes?
Mostly, yes. Standard colors like Red (10A), Blue (15A), Yellow (20A), and Green (30A) are consistent across all sizes, although Maxi fuses also include higher ratings like 80A or 120A with custom colors.
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