A coolant calculator for metalworking fluids turns a refractometer reading and a sump volume into a concentration and a mix or top-up volume; this section holds 3 tools: one calculator and two request tools. Results are in % by volume of concentrate in the diluted fluid. Which tool answers which shop question?
The calculator covers water-miscible metalworking fluids (soluble oils, semi-synthetics and synthetics) diluted with water, in 4 modes. A reading becomes a percentage only through the product's own refractometer factor (UKLA/HSE Good Practice Guide v2.5, February 2025). The provider match covers 6 service categories, from chemical management services to disposal.
Standards, regulations and exposure limits are checked against their issuing bodies, product values against the named data sheet, and every figure carries its source and date; see our methodology and fact-checking.
Every Tool in This Section#
This section lists 3 tools for metalworking fluids: a concentration and mixing calculator, a supplier request for quotes and a provider match for coolant management and recycling. The table compares inputs and outputs.
| # | Tool | What it does | Inputs the reader gives | What the reader gets |
|---|---|---|---|---|
| 1 | Coolant concentration and mixing calculator | converts a refractometer reading to concentration and computes new-charge, top-up and drain-down volumes for water-miscible metalworking fluids | refractometer reading (°Brix), product refractometer factor, sump volume, current volume and concentration, target concentration in % by volume | concentration in % by volume of concentrate in the diluted fluid; concentrate and water volumes in L (US gal); premix strength |
| 2 | Request quotes for metalworking fluids and additives | sends one specification to independent suppliers | fluid type or additive class, operation, material, machines and sump volume, water, excluded chemistries, annual volume, region | quotes from independent suppliers |
| 3 | Find a coolant management or recycling provider | passes a service request to independent providers | service category, number of machines or central system, sump volume, region | contact from independent providers |
Calculator results are in % by volume of concentrate in the diluted fluid; volumes in liters with US gallons.
The order runs from calculating to sourcing.
Which Tool Fits Which Task?#
Each tool answers one kind of shop question: the calculator gives concentrate and water volumes, the RFQ finds supply for a fluid or additive, and the provider match finds management, testing or recycling. The table maps 6 shop tasks to the tool and mode that handles them.
| Task | Tool | Why |
|---|---|---|
| Convert a refractometer reading to concentration | calculator, mode 1 | reading x product refractometer factor |
| Fill an empty sump to a target concentration | calculator, mode 2 | concentrate and water volumes from total volume and target |
| Bring a lean sump back to target | calculator, mode 3 | top-up concentrate, water and premix strength |
| Bring a rich sump back to target | calculator, mode 4 | water only, or drain first when capacity is short |
| Source a fluid, forming lubricant, rust preventive or additive | supplier RFQ | one specification to independent suppliers |
| Hand over management, testing, recycling, sump cleaning or disposal | provider match | one request to independent providers |
A volume balance corrects how much concentrate and water a sump holds, not the condition of the fluid itself. Lab testing and fluid audits, one of the 6 provider-match categories, examine the fluid.
What the Metalworking Fluid Calculator Needs and Returns#
The metalworking fluid calculator works in four modes (reading to percent, new charge, top-up and rich-sump drain-down), and each mode needs the product's refractometer factor from its supplier's data sheet. The four modes are listed below with their inputs and outputs.
- Reading to percent: °Brix reading and product factor give % by volume; optional titration check.
- New charge: total volume and target give concentrate and water volumes.
- Top-up: current volume and concentration give concentrate, water and premix strength.
- Rich-sump drain-down: water only, or a drain volume first when capacity is short.
A Brix reading equals the concentration only when the product's factor is 1.0, because concentration is the reading, zeroed on the mix water at about 20 °C (68 °F), times that factor (UKLA/HSE Good Practice Guide v2.5, February 2025). Like any cnc coolant calculator, this one returns a wrong volume from a wrong factor, so titration is the check method named in mode 1.
Volumes are in L first with US gallons in parentheses. On the same basis, 5 % equals 1 part concentrate in 20 parts total, or 19:1 water to concentrate. The unit constants are exact: 1 US gal = 3.785411784 L (231 in³), and 1 % equals 10,000 ppm.
What the Metalworking Fluid Request Tools Send and to Whom#
The two request tools send one specification to independent suppliers or providers: the RFQ covers fluids, forming lubricants, rust preventives and additive chemistry, and the provider match covers management, testing, recycling and disposal services. No ISO or ASTM document defines a metalworking fluid RFQ, so this reference's RFQ checklist has 8 elements, listed below.
- Application: operations, tooling, finish and tolerance.
- Materials: alloys and staining limits.
- Machines and system: sumps or central system, volume, filtration.
- Water: hardness in ppm as CaCO3, chloride, sulfate.
- Constraints: excluded chemistries such as chlorine, boron and nitrite.
- Commercials: annual volume; drum 208 L (55 US gal), IBC 1,000 L (264 US gal) or bulk.
- Trial: machines, duration and success metrics.
- Service level: visits, tests and reporting.
The provider match has 6 categories: chemical management services, coolant management programs, on-site or batch recycling, sump cleaning and recharge, lab testing and fluid audits, and disposal and haul-away. The US EPA scopes chemical management services from procurement to disposal.
Quotes are compared on cost per L of working fluid, which equals the concentrate price times the concentration, never on concentrate price alone. In this reference's worked example (2026), a concentrate at USD 10/L used at 5 % costs USD 0.50 per L of working fluid, about USD 1.89 per US gal. Top-up, tankside additives, disposal and service fees are then added.
Before You Calculate: Measuring the Inputs#
A calculator result is only as accurate as the two inputs a shop measures, the concentration reading and the fluid volume in the sump.
Reading concentration for the calculator#
The concentration reading fed to the calculator comes from a refractometer zeroed on the mix water at about 20 °C (68 °F) (UKLA v2.5). UK guidance checks concentration at least weekly with a refractometer, together with pH (HSE COSHH essentials MW5, 03/21).
Coolant concentration has more methods than one reading. The guide to coolant concentration explains refractometer readings, correction factors and titration in full.
Topping up between calculations#
A top-up adds premix below the target concentration, because evaporation concentrates the sump. Neat water or neat concentrate is never the routine top-up (HSE MW5, 03/21).
Premix is made by adding concentrate to water, never water to concentrate (UKLA v2.5 section 4.1). Mode 3 returns the premix strength.
Does the calculator convert water hardness?#
Not as a separate tool (October 2026): water hardness is handled on the mix-water page, where 1 grain per US gallon equals 17.12 mg/L (ppm) as CaCO3. Mix-water quality enters a supplier request as hardness in ppm as CaCO3. The page on water quality for metalworking fluids covers hardness, chlorides and deionized water.