Laundry Detergent Calculator
Dose laundry soap per load and per month from machine and soil.
What it does
Detergent works in a narrow band. Too little leaves body oil in fibers, too much leaves film that traps odor, and HE machines punish excess hardest.
The tool above doses from machine, load, and soil. An HE large load with normal soil needs 2 fl oz, which at 8 loads a week is 69 fl oz a month, with a cap of 2.5 fl oz. Metric kitchens get 59 ml per load and 2,049 ml a month.
Base amounts carry the load size. Small, medium, and large map to 1, 1.5, and 2 fl oz in HE drums, doubled for deep fill standard machines. Soil then scales the base down for office wear or up for work gear.
Loads per week close the month math. Eight loads is common for a family of four, while singles may run three and large households may run twelve. The 4.33 factor turns weeks into an average month.
The cap line guards the drum. Doses above 1.25 times need should go to pretreat and second rinse, not to extra soap in the dispenser.
How to use
- Pick imperial (fl oz) or metric (ml).
- Pick machine: HE or standard.
- Pick load: small, medium, or large.
- Pick soil: light, normal, or heavy.
- Enter loads per week.
- Read per load, monthly, and cap in order.
Formula
- machine
- HE or standard machine.
- load
- Small, medium, or large load.
- soil
- Light 0.75, normal 1, heavy 1.5.
- loads
- Wash loads per week.
Base is 1, 1.5, or 2 fl oz for small, medium, and large HE loads, doubled for standard machines. Metric converts at 29.5735 ml per fl oz.
Worked example
Example: HE large, normal soil
Imperial defaults: HE machine, large load, normal soil, 8 loads per week. These are also the default values, so the page opens on this answer.
- Machine: HE. Load: large, so base is 2 fl oz.
- Soil: normal, so multiplier is 1.
- Per load: 2 x 1 = 2 fl oz.
- Loads: 8 per week.
- Month: 2 x 8 x 4.33 = 69 fl oz.
- Cap: 2 x 1.25 = 2.5 fl oz. Tool shows 2 fl oz per load, 69 fl oz per month, Do not exceed 2.5 fl oz.
Reference table
| Machine | Load | Per load |
|---|---|---|
| HE | Small | 1 fl oz |
| HE | Medium | 1.5 fl oz |
| HE | Large | 2 fl oz |
| Standard | Large | 4 fl oz |
Limits
- Liquid dosing guide only. Pods and sheets follow maker labels.
- Hard water and old machines shift results.
- Stains need pretreat, not whole load doubles.
- Scent and dye needs sit outside soap math.
Common mistakes
- Pouring freehand into the cap lines.
- Doubling soap for stains instead of pretreating.
- Using standard doses in an HE drum.
- Washing cold with too much soap and no extra rinse.
- Buying bulk with no monthly plan, then running out.
Try it yourself
Quick checks. Answers sit tucked under each question.
HE small, light soil, 4 loads?
HE small is 1 fl oz. Light is 0.75, so 1 x 0.75 = 0.8 fl oz per load. Month at 4 loads is 0.75 x 4 x 4.33 = 13 fl oz. Cap is 0.75 x 1.25 = 0.9 fl oz.
Standard medium, heavy soil?
Standard medium is 1.5 x 2 = 3 fl oz. Heavy is 1.5, so 3 x 1.5 = 4.5 fl oz per load.
Questions
How much per load?
Multiply base by soil share. HE large is 2 fl oz, normal is 1, so 2 fl oz per load.
What are the base amounts?
Small 1, medium 1.5, large 2 for HE, doubled for standard. Light 0.75, normal 1, heavy 1.5.
How much per month?
Multiply per load by loads per week by 4.33. Here 2 x 8 x 4.33 = 69 fl oz.
Can too much harm HE washers?
Yes. Suds cushion in HE drums, so extra soap leaves film and odor. Measure, do not pour freehand.
Still stained?
Use the cap line at 1.25 times the dose. If stains persist, pretreat instead of doubling the whole load.
Does this cover pods?
No. Pods, sheets, and concentrates follow maker labels. This page doses liquid ratings.