Free tool · Two-stroke
Two-stroke fuel mix calculator
Calculate the oil to add to petrol, the petrol for a bottle of oil, or the mathematical correction of a known mixture.
Your mix
A 2% mix means 20 ml of oil per litre of petrol, or 1:50. The percentage is relative to petrol alone; the oil is added on top of that volume.
Enter the petrol volume alone, before adding oil.
Oil percentage relative to petrol. ≈ marks a rounded percentage; calculations keep the exact proportion in brackets.
Comma or decimal point accepted. Volumes from 0.001 to 1,000 L; oil from 1 to 100,000 ml; proportions from 1:10 to 1:200. These bounds limit input mistakes and the calculator’s scope: they are not a safe operating range for your engine.
Result
1:50 · 2% oil relative to petrol
100 ml
of oil to add to the entered petrol
Theoretical total volume: 5.1 L
Oil rounded to the nearest ml; litres rounded to 0.001 L. Total uses unrounded values. This calculation guarantees neither measurement accuracy nor suitability of the mixture.
The link contains your input values, with no account submission or database storage.
How the calculation works
Oil (ml) = petrol (L) × percentage × 10. At 2%, each litre of petrol therefore needs 20 ml of oil. In reverse, petrol (L) = oil (ml) ÷ (percentage × 10). A proportion of 1:50 means 100 ÷ 50 = 2%.
The calculation first separates the total volume into petrol and oil using the known current dosage. To increase the oil percentage, it calculates the missing oil; to reduce it, the petrol to add. If both dosages match, nothing is added.
Correction assumes a known current volume and ratio and a homogeneous mixture. An unknown ratio cannot be recovered by this calculator. It does not diagnose fuel, compatibility or possible engine damage: consult your manual and, if in doubt, a professional.
References read in manufacturer manuals
Only the listed models and years, with no extrapolation across brands or years. Ratios are displayed as oil:petrol. Oil and conditions are part of the recommendation; read the full document. No reference ratio is automatically applied to the calculator.
| Model · year | Ratio | Oil and conditions | Document and original excerpt |
|---|---|---|---|
| KTM 125 SX (EU)2025 | 1:402.5% | 98 RON petrol + fully synthetic JASO FD two-stroke oil; Motorex Cross Power 2T recommended (pp. 141–142). | Owner’s Manual 2025 · 3240041en · p. 142 (PDF 144)Mixture ratio 1:40Read on 2026-10-17 |
| KTM 150 SX (EU)2025 | 1:402.5% | 98 RON petrol + fully synthetic JASO FD two-stroke oil; Motorex Cross Power 2T recommended (pp. 141–142). | Owner’s Manual 2025 · 3240041en · p. 142 (PDF 144)Mixture ratio 1:40Read on 2026-10-17 |
| KTM 250 SX (EU)2025 | 1:601.667% | 95 RON petrol + fully synthetic JASO FD two-stroke oil; Motorex Cross Power 2T recommended (pp. 139–140). | Owner’s Manual 2025 · 3240042en · p. 140 (PDF 142)Mixture ratio 1:60Read on 2026-10-17 |
| Husqvarna TC 125 (EU)2025 | 1:402.5% | 98 RON petrol + two-stroke engine oil; DIN EN 228 and JASO FD in the fuels section. | Owner’s manual 2025 · 3402801en · p. 142 (PDF 142)Mixture ratio 1:40Read on 2026-10-17 |
| Husqvarna TC 250 (EU)2025 | 1:601.667% | 95 RON petrol + two-stroke engine oil; DIN EN 228 and JASO FD in the fuels section. | Owner’s manual 2025 · 3402802en · p. 152 (PDF 152)Mixture ratio 1:60Read on 2026-10-17 |
| GASGAS MC 125 (WW)2025 | 1:402.5% | 98 RON petrol + two-stroke engine oil; DIN EN 228 and JASO FD in the fuels section. | Owner’s manual 2025 · 3215219en · p. 136 (PDF 136)Mixture ratio 1:40Read on 2026-10-17 |
| Yamaha YZ125 / YZ125S2025 | 1:303.333% | Yamalube 2R. Normal ratio 30:1; separate break-in ratio of 15:1 on the same page: follow the whole procedure, not this normal-use reference for break-in. | Owner’s Manual 2025 · D68-28199-50 · p. 1-16 (PDF 26)YAMALUBE 2R Premix ratio 30Read on 2026-10-17 |
| Yamaha YZ250 (YZ250M2)2021 | 1:303.333% | Yamalube 2R. Normal ratio 30:1; follow the manual’s break-in procedure separately. | Owner’s Service Manual 2021 · BF1-2819U-10 · p. 1-18 (PDF 30)YAMALUBE 2R Premix ratio 30Read on 2026-10-17 |
| Sherco 125 SE Racing / Factory2025 | 1:502% | Unleaded 95 RON petrol with 2% two-stroke oil (p. 7); Motorex Cross Power 2T listed under consumables (p. 9). | Owner’s Manual · 125 SE · 2025 · p. 7, 9 (PDF 7)mélangé avec de l’huile moteur 2 temps (2%)Read on 2026-10-17 |
| Sherco 250 / 300 SE Racing / Factory2025 | 1:502% | Unleaded 95 RON petrol with 2% two-stroke oil (p. 7); Motorex Cross Power 2T listed under consumables (p. 9). | Owner’s Manual · 250–300 SE · 2025 · p. 7, 9 (PDF 7)mélangé avec de l’huile moteur 2 temps (2%)Read on 2026-10-17 |
Separate-lubrication examples: no premix
If your motorcycle has separate oil injection, do not premix unless its manual explicitly instructs you to. The documented examples below prohibit refueling with premixed fuel.
KTM 250 EXC TPI (EU) · 2022
Owner’s Manual 2022 · 3214421en · p. 49 (PDF 51)Do not refuel using pre-mixed fuel.
Read on 2026-10-17
Husqvarna TE 250 (EU / US) · 2025
Owner’s manual 2025 · 3402807en · p. 54 (PDF 54)Do not refuel using pre-mixed fuel.
Read on 2026-10-17
GASGAS EC 250 (EU / US) · 2025
Owner’s manual 2025 · 3215225en · p. 51 (PDF 51)Do not refuel using pre-mixed fuel.
Read on 2026-10-17
Frequently asked questions
How much oil for 5 L at 2%?
For 5 L of petrol alone at 2% (1:50), add 100 ml of oil. The theoretical total is 5.1 L. The 2% is relative to petrol, not the final mixture.
Are 50:1 and 1:50 the same?
Yes, when 50:1 means petrol:oil and 1:50 means oil:petrol: one volume of oil for 50 volumes of petrol, or 2%. Always check the order of the components in your document.
What if I got the mixture wrong?
Use “Correct a mixture” with the known total volume and current ratio. For example, 5.1 L at 1:50 needs 25 ml of extra oil to reach 1:40. An unknown current ratio cannot be inferred here; the manual and oil data sheet take priority.