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Short answer: there is no single, universal pH strip color chart. Each manufacturer prints its own chart, and the colors on it belong only to that maker’s strips. To read a strip, match it to the chart supplied with that same product, within the time the maker states. This page covers what the scale looks like, how to read a chart correctly, and the handling mistakes that change a reading.
General product information only, not medical advice. For any health question, ask a qualified clinician.
The pH scale and what a strip chart shows
A pH strip is a plastic or paper carrier with one or more reactive pads. After the pad contacts a liquid, it changes color, and the color is compared with a printed chart whose blocks are labeled with pH values. The chart is a lookup tool for that product only: a colored block on one brand’s chart does not tell you what the same shade means on another brand’s chart.
What differs between products is the range and the step size. As one documented example, the Hydrion 9800 plastic strips from Micro Essential Laboratory are described in the maker’s data sheet (checked 2026-10-30) as giving color matches at every 1.0 interval from pH 0.0 to 14.0.
| Item | Hydrion 9800 data sheet |
|---|---|
| Range | pH 0.0 to 14.0 |
| Reading points | 0.0, 1.0, 2.0, 3.0 … 13.0, 14.0 (every 1.0) |
| Strip size | 2 3/4 in x 1/4 in |
| Supplied as | 100 strips per flip-top vial, with a matching color chart |
The colors for each of those 15 reading points are not listed here on purpose. They are printed on the chart that comes with the vial, and that chart is the only authoritative key for those strips.
How to read a pH strip color chart
The Lovibond (Tintometer) method reference for its pH 0-14 plastic strips (checked 2026-10-30) gives this sequence:
- Remove one strip and hold it by the end between index finger and thumb.
- Dip the strip into the sample so that all pads are completely immersed.
- Shake off excess liquid.
- Compare the strip color with the colour chart provided, within 30 seconds, and read the result from the colour scale.
The Hydrion data sheet gives the same idea in fewer steps: dip the strip in the test solution, remove it, and immediately compare the resulting color with the matching pH color chart. The two makers state the timing differently (“within 30 seconds” versus “immediately”), which is a reminder to follow the instructions printed with your own strips.
How to choose a strip: range and step size
Two printed specifications let you compare strips honestly. The first is the range, such as 0 to 14. The second is the interval between chart blocks, such as the 1.0 steps in the Hydrion example above. A strip can only report the reading points on its chart, so a chart with 1.0 steps reports whole-number values and does not resolve differences smaller than that.
Strip versus meter: what the difference means
A strip result is a visual comparison against a chart, so it is an estimate. A pH meter measures with an electrode and a display, and it is calibrated against buffers. If you need a measured value rather than a visual match, see what a pH meter is and pH meter calibration and buffer selection. For making the solutions themselves, see the buffer and solution preparation guide.
In the United States, strips sold to test urine fall under a named device type. 21 CFR 862.1550 (checked 2026-10-30) defines a urinary pH (nonquantitative) test system as a device intended to estimate the pH of urine, and classifies it as Class I, exempt from premarket notification subject to the limitations in 21 CFR 862.9. A related multi-test product is covered in ketones in urine test strips.
Common mix-ups that change the reading
Reading too late or too early
The colors on a chart correspond to the reading window the maker specifies (Lovibond: within 30 seconds). Reading later than that is not what the chart was made for.
Touching the pads
Lovibond instructs users to touch strips only at the end, and says the pads must not come into contact with the fingers.
Storing strips open
Lovibond states that test strips must be stored in the closed packaging.
Not fully immersing the pads
Both makers describe dipping the strip into the solution; Lovibond specifies that all pads are completely immersed, then excess liquid is shaken off.
Using the wrong chart
Both makers supply a chart with the strips (Lovibond: “the colour chart provided”; Hydrion: a “matching” chart). A chart from another product is not a valid key for your strips.
FAQ
Is there a standard pH test strip color chart?
No standard chart is used across brands. Each product ships with its own chart, as in the Hydrion vials that are packaged with matching color charts. Use the chart that came with your strips.
What do pH test strip colors mean?
Each color block on the chart is labeled with the pH value it represents for that product. The same shade can carry a different value on another brand’s chart, so read the label printed on your chart, not a color from memory or from another source.
What is the difference between pH paper and pH strips?
For reading purposes the rule is the same for any chart-based pH indicator product: compare the result with the chart supplied by that product’s maker, in the time the maker states. The two makers cited here describe their products as strips.
How long should I wait before reading the strip?
Follow the time stated by your strip’s maker. Lovibond states comparison within 30 seconds; the Hydrion data sheet says to compare immediately after removing the strip.
Check your product’s labelling
Before relying on a reading, check the label and chart that came with your own strips for the range, the interval between readings, the reading time and the storage conditions. Those printed instructions take precedence over any general description on this page.
Sources
- Lovibond (Tintometer), Method Reference Book, “pH Strips pH 0-14 Plastic”: lovibond.com/en/file-download/f172447_en (checked 2026-10-30).
- Micro Essential Laboratory, Hydrion plastic pH strips 0-14 (9800) data sheet: microessentiallab.com, 9800_Lit-22.pdf (checked 2026-10-30).
- 21 CFR 862.1550, Urinary pH (nonquantitative) test system: law.cornell.edu/cfr/text/21/862.1550 (checked 2026-10-30).
