Free Tool
2-Stroke Premix Ratio Calculator
Enter how much fuel you are mixing and the ratio your bike needs. The calculator gives you the oil to add in US fluid ounces and milliliters, and the table below shows the ratios printed in current owner's manuals.
Premix Ratio Calculator
Mix in a clean, approved fuel can. Your owner's manual is the authority for your bike's ratio and oil type.
How The Premix Calculator Works
A 2-stroke ratio is written as fuel to oil. At 40:1 (KTM prints it as 1:40) you add one part oil for every 40 parts fuel. The calculator divides your fuel volume by the ratio: one US gallon is 128 US fluid ounces or 3,785 ml, so 1 gallon at 40:1 needs 128 / 40 = 3.2 oz (about 95 ml) of oil. In liters it is simpler: 1,000 ml / 40 = 25 ml of oil per liter.
Results are rounded for the measuring cup in your garage. Measure oil with a marked ratio cup or syringe, not by eye, because small errors add up fast in a 1 gallon batch.
OEM Premix Ratios By Model
Manufacturers do not agree on one ratio, which is why the "right" mix starts a lot of arguments. These are the ratios printed in current owner's manuals:
| Model | Ratio | Fuel and oil notes | Source |
|---|---|---|---|
| KTM 125 SX / 125 XC (2026) | 40:1 (1:40) | Super unleaded, 98 octane (ROZ/RON) | KTM 2026 125 SX / 125 XC owner's manual |
| KTM 250 SX / 300 SX / 250 XC / 300 XC (2026) | 60:1 (1:60) | Super unleaded, 95 octane, JASO FD oil | KTM 2026 250 SX / 250 XC / 300 SX / 300 XC owner's manual |
| KTM 85 SX (2026) | 40:1 (1:40) | 1:30 during the first ten operating hours | KTM 2026 85 SX owner's manual |
| Husqvarna TC 125 (2026) | 40:1 (1:40) | Super unleaded, 98 octane, JASO FD oil | Husqvarna 2026 TC 125 owner's manual |
| Husqvarna TC 250 / TX 300 (2026) | 60:1 (1:60) | Super unleaded, 95 octane, JASO FD oil | Husqvarna 2026 TC 250 / TX 300 owner's manual |
| GASGAS MC 125 (2026) | 40:1 (1:40) | Super unleaded, 98 octane, JASO FD oil | GASGAS 2026 MC 125 owner's manual |
| GASGAS MC 250 / EX 300 (2026) | 60:1 (1:60) | Super unleaded, 95 octane | GASGAS 2026 MC 250 / EX 300 owner's manual |
| Yamaha YZ125 (2026) | 30:1 (1:30) | Yamalube 2R; 15:1 break-in mixture | Yamaha 2026 YZ125 owner's service manual |
| Yamaha YZ250 (2026) | 30:1 (1:30) | Yamalube 2R | Yamaha 2026 YZ250 owner's service manual |
| Beta RR 125 (2025, US) | 40:1 (1:40) | Listed as 2.5% oil; Europe model 2% | Beta 2025 RR 2-stroke Xpro owner's manual |
Oil-injected models do not use premix in normal riding. The 2026 KTM 300 XC-W and 300 EXC, the Husqvarna TE 300 and the 2025 Beta RR 2-stroke Xpro models meter oil from a separate tank. The Beta manual still calls for a 1% premix in the first tank during break-in.
Quick Mixing Chart
Use this chart when you do not have your phone in the garage. Values are oil to add for the fuel amount on the left.
| Fuel | 32:1 | 40:1 | 50:1 | 60:1 |
|---|---|---|---|---|
| 0.5 US gal | 2.0 oz (59 ml) | 1.6 oz (47 ml) | 1.3 oz (38 ml) | 1.1 oz (32 ml) |
| 1 US gal | 4.0 oz (118 ml) | 3.2 oz (95 ml) | 2.6 oz (76 ml) | 2.1 oz (63 ml) |
| 2 US gal | 8.0 oz (237 ml) | 6.4 oz (189 ml) | 5.1 oz (151 ml) | 4.3 oz (126 ml) |
| 2.5 US gal | 10.0 oz (296 ml) | 8.0 oz (237 ml) | 6.4 oz (189 ml) | 5.3 oz (158 ml) |
| 5 US gal | 20.0 oz (591 ml) | 16.0 oz (473 ml) | 12.8 oz (379 ml) | 10.7 oz (315 ml) |
| 1 L | 31 ml | 25 ml | 20 ml | 17 ml |
| 5 L | 156 ml | 125 ml | 100 ml | 83 ml |
| 10 L | 312 ml | 250 ml | 200 ml | 167 ml |
| 20 L | 625 ml | 500 ml | 400 ml | 333 ml |
How To Mix Premix Correctly
- Start with fresh fuel of the octane your manual lists.
- Pour about half the fuel into a clean can, add the full measured oil, then add the rest of the fuel. This helps it blend.
- Close the can and shake it well. Shake again before you fill the bike if it has been sitting.
- Label the can with the ratio and the date.
- Use it soon. Yamaha's YZ manuals warn against using premix that is more than a few hours old, and KTM says to mix only as much as you need.
Use the 2-stroke oil class your manual calls for. KTM, Husqvarna and GASGAS manuals specify JASO FD oil. Do not mix brands or types in one batch, and do not run 4-stroke oil in premix.
Is A Richer Mix Safer?
Not automatically. More oil means less fuel in the same volume, which leans the air-fuel mixture slightly unless the bike is rejetted or remapped, and it can foul plugs and build carbon on the power valve and exhaust. Less oil than specified risks scuffing the piston. Running the manual's ratio with the oil it specifies is the baseline the engine was developed on. If you change ratios, check plug color and jetting, and talk to your dealer or engine builder first.
For the full background, read our 2-stroke premix ratio guide.
Track Fuel And Top-End Hours
Premix is only half of 2-stroke care. The top end runs on hours: the 2026 KTM 125 SX manual puts the minor engine service, which includes a new piston, at 15 operating hours. MotoMind tracks those service intervals by engine hours and logs fuel and spending per bike, so you can see what each tank and each top end really costs.
FAQ
How much oil do I mix per gallon at 40:1?
128 US fluid ounces divided by 40 is 3.2 ounces, or about 95 ml, of 2-stroke oil per US gallon of fuel.
How much oil per gallon at 50:1?
2.56 US fluid ounces, about 76 ml, per US gallon.
How much oil per liter at 32:1?
1,000 ml divided by 32 is about 31 ml of oil per liter of fuel.
What premix ratio does a KTM 125 SX use?
The 2026 KTM 125 SX owner's manual specifies a 1:40 mixture (40:1) with super unleaded 98 octane fuel.
What premix ratio does a Yamaha YZ125 or YZ250 use?
Yamaha's 2026 YZ125 and YZ250 owner's service manuals list a premix ratio of 30 (30:1) with Yamalube 2R, and the YZ125 manual calls for a 15:1 mixture for the break-in tank.
Is 1:40 the same as 40:1?
Yes. KTM, Husqvarna and GASGAS print the ratio as oil to fuel (1:40) and many riders say fuel to oil (40:1). Both mean one part oil to 40 parts fuel.
How long does premix last?
Not long. Yamaha's YZ manuals warn against using premix that is more than a few hours old, so mix what you need for the ride and label the can with the date.
Sources
- KTM 2026 125 SX / 125 XC owner's manual
- KTM 2026 250 SX / 250 XC / 300 SX / 300 XC owner's manual
- KTM 2026 85 SX owner's manual
- Husqvarna 2026 TC 125 owner's manual
- Husqvarna 2026 TC 250 / TX 300 owner's manual
- GASGAS 2026 MC 125 owner's manual
- GASGAS 2026 MC 250 / EX 300 owner's manual
- Yamaha 2026 YZ125 owner's service manual
- Yamaha 2026 YZ250 owner's service manual
- Beta 2025 RR 2-stroke Xpro owner's manual
- KTM 2026 300 XC-W / 300 EXC owner's manual (oil injection)
- Husqvarna 2026 TE 300 owner's manual (oil injection)
Track Every Tank And Every Top End
MotoMind logs fuel and spending per bike and tracks top-end and gear oil intervals by engine hours, so your 2-stroke stays on schedule.
