ConvertAll Help

Everything ConvertAll can do, step by step.

Last Updated: November 15, 2026

1. Getting Started

ConvertAll opens on the length converter. Above it are four tabs: Convert (the converter and the tools), Browse (the list of categories and tools, shown beside the converter from 1024 pixels wide, so the tab appears only on narrower screens), Saved (saved pairs and recent conversions) and Settings. The question mark button opens a short help window. Everything happens on this page; nothing is uploaded and there is no account.

2. The Search Bar

The bar above the converter reads whole conversions: type "5 ft 11 in to cm", "72 f to c", "65 mph in km/h", "2 m + 30 cm in ft" or "500 GB to GiB" and press Enter to open the first match, or use the arrow keys to pick another. "to", "in", "into", "as", "=" and "->" all mark the target. Without a target, such as "30 psi", it suggests the usual targets for that unit. Typing a name instead, such as "pressure", "bigha" or "oven", offers the category, unit or tool. The bar takes up to 200 characters.

3. The From and To Boxes

Type in either box and the other follows. Below each box a menu picks the unit; the round button between them swaps the units. Both boxes read:

• Fractions: 3/4, 1 1/2 or 1½.
• Powers and sums: 2.5e3, 2.5 x 10^3, (12 + 8) * 3.
• Values with units of the same kind: 5 ft 11 in, 5' 11", 2 m + 30 cm, 1 h 30 min. A bare number after feet, stone, pounds, hours, minutes or degrees is the next smaller unit: 5'11, 10 st 4, 1 h 30. A bracket straight after a value multiplies: 2(3 + 4) is 14.

A note under the box shows how the text was read, and the mixed form of the answer, such as 5 ft 10.9 in, 11 st 4 lb or 1 h 30 min (switch this off in Settings). Under the boxes the result line gives the answer, a tag (Exact, Rounded or Approximate), the formula and the values of 1 of each unit. Exact means every digit is shown, Rounded that more exist, and Approximate that one unit has no single fixed size, such as a regional bigha or an em.

4. Categories and Units

Thirty-three categories hold over 370 units: length, weight, volume, area, temperature, speed, time, fuel economy, data storage, data speed, typography and screen, pressure, energy, power, force, frequency, angle, density, torque, acceleration, flow rate, dynamic and kinematic viscosity, electric current, voltage, resistance, electric charge, capacitance, illuminance, radiation dose, dose equivalent, radioactivity and magnetic field. In each, the unit menus group metric, US and imperial, Indian, scientific and other units. The quick pairs row above the boxes holds the usual pairs and the ones you saved.

The factors are the published definitions: NIST Special Publication 811 (2008) and NIST Handbook 44 (2026) for US and imperial units, on the international foot (the US survey foot was retired at the end of 2022); the SI Brochure; CODATA 2022 for the dalton, the elementary charge and the faraday; the CSS standard for screen units (96 pixels to the inch; em and rem are shown for a 16 px base); NIST's binary prefixes for KiB and MiB; the US nutrition label rule for the 240 mL cup; and the Standards of Weights and Measures Act, 1976 for the tola (11.6638038 g), seer and maund. Traditional Indian land measures differ by place, so each is named with the size it uses and marked approximate; check your land records before relying on one.

Twenty-four units came over from UnitSwap, the site's earlier unit converter, when it became part of ConvertAll on 15 November 2026: the Delisle, Rømer and Newton temperature scales; the square rod, the rood and the barn; centimetres, inches and miles per second; the shake; the exabyte; the milliwatt, the calorie per second and boiler horsepower; the meganewton; cycles and frames per second; the quadrant, the sextant and the sign; tonnes and milligrams per cubic metre and slugs per cubic foot; and the millinewton-metre. Their sizes are NIST Special Publication 811's where it lists them, otherwise those of the dictionary of units kept at the University of North Carolina and the two fixed points of each temperature scale. The Delisle scale counts downwards (0 where water boils, 150 where it freezes), so on its tape the part above absolute zero's number is the shaded one. The Newton scale is marked approximate. Typed exactly, mW is the milliwatt and MW the megawatt; in small letters, mw still means megawatt.

5. The Tape

The yellow tape shows the From unit on its top edge and the To unit on its bottom edge, with the red needle at your value, so you can read the values around it at a glance. Drag the tape sideways, or click it and use the arrow keys (Page Up and Page Down take bigger steps, Home goes to zero), to change the value. Plus and minus zoom the scale. Values that make no sense, such as a negative length or a temperature below absolute zero, are shaded, and a temperature below absolute zero gets a line saying so.

6. Every Unit at Once

Under the tape the value appears in every unit of the category. Type in Filter units to find one, click a unit's name to make it the To unit, use the copy button to copy its value with the unit, and the pin button to move it to the top of the list for that category.

7. Saved Pairs, Recent Conversions and Links

Save pair keeps the two units in the quick pairs row (with a star) and under the Saved tab. Copy copies the result line. Link copies a link to the conversion on screen (on a phone it opens the share sheet); whoever opens it sees the same units and value, and the link is taken out of the address once read. A conversion goes into the recent list when you type a value, drag the tape or use the search bar, not when you only pick units. The Saved tab lists your saved pairs and up to 100 recent conversions, newest first; open one with a click, remove one with its cross, or clear each list.

8. Settings and Number Formats

• Number format: 1,234,567.89, the Indian 12,34,567.89, 1.234.567,89, 1 234 567,89 or 1234567.89. It also sets how typed numbers are read.
• Precision: automatic (every digit when the answer has up to 12 significant digits, otherwise 10, with a long whole part written in full), whole numbers, or 2 to 10 decimal places. Precision shapes the answers only: what you typed stays as typed.
• Very large and very small numbers: scientific notation only when needed, always, or engineering notation (powers of 1,000).
• Mixed units: show answers such as 5 ft 10.9 in under the boxes.
• Your data: export your saved pairs and recent conversions as a JSON file, or reset everything.

The page's light and dark themes follow the round button at the top right of the site.

9. Kitchen Tools

Cooking turns cups and spoons into grams and back for over 40 ingredients, from flour, atta and besan to sugar, rice, dals, butter and ghee. The weights of a cup are the U.S. Department of Agriculture's (FoodData Central, SR Legacy); for baking powder, baking soda and yeast they come from USDA's teaspoon weights. Choose Other to type the grams in one cup yourself. Cups come as the US cup (236.6 mL) and the 250 mL cup, spoons as US and 5 or 15 mL spoons.

Recipe scaler: paste a recipe (up to 20,000 characters) and scale it by a factor or by servings; amounts are rounded to kitchen fractions, and a decimal comma (1,5 l) or a thousands mark (1,000 g) is read as well. Keep "only the amount at the start of each line" on so oven temperatures, pan sizes and times stay as they are.

Oven temperature: type a temperature in °C, °F or a gas mark from 1 to 9. The chart, with a fan oven column 20 °C lower, follows the oven chart of Which?, the UK consumer body.

10. Size Charts

Clothing (women's tops and dresses, men's shirts, men's trousers), shoes (men's and women's, from your foot length) and rings (from the inside diameter or circumference) line up sizes between countries. They are example charts: there is no single standard between countries, and brands and jewellers each size a little differently, so check their own chart before you buy. Type your measurement to highlight the closest row. A measurement outside a chart is said to be outside it, and no size is named. In the ring chart a US size adds 0.8128 mm to the diameter, EU sizes are the inside circumference in millimetres, and UK letters sit beside the nearest US size.

11. Trip Fuel Cost, Tyres and Time Zones

Trip fuel cost: type the distance, your car's fuel economy (km per litre, litres per 100 km or miles per gallon) and the fuel price you pay; it shows the fuel needed, the cost in total, per person, per km and per mile. The carbon dioxide counts only the fuel burnt, from the US EPA's figures (8,887 g for a US gallon of petrol, 10,180 g for diesel).

Tyre sizes: type a size such as 205/55R16 to see its sidewall, overall diameter, circumference and revolutions per kilometre, drawn to scale; add a second size to compare them and see your real speed when the speedometer shows a value.

Time zones: pick a base city and a moment (or Now, which updates every 30 seconds) and add cities (a country with one time, such as India, or a big city missing from the browser's list, such as Mumbai or Beijing, adds the listed city that keeps the same time); each shows its local time, its offset from UTC and the difference, with daylight saving from your browser's time zone data.

12. Number Bases, Paper Sizes and Wire Gauges

Number bases: whole numbers of up to 1,000 digits between binary, octal, decimal, hexadecimal and any base from 2 to 36, with the size in bits and bytes and a copy button for each.

Paper and photo sizes: A and B sizes (ISO 216), C sizes and the DL envelope (ISO 269), US Letter, Legal and Tabloid and common photo sizes, in millimetres, centimetres, inches or points, with the pixels needed at a print resolution. Click a row to draw it beside A4.

Wire gauge: American Wire Gauge sizes 0000 to 40 with their diameter, area, the resistance of annealed copper at 20 °C and the nearest metric size. Find a size by its AWG number or its area in mm². The table gives sizes only: choose a cable by your local electrical code and the cable maker's ratings.

13. BMI

Type your height and weight in metric or feet, inches and pounds. Choose the WHO's cut-offs (18.5, 25 and 30) or, for India, the India Obesity Commission's revised definition of 2025 (normal 18.5 to 22.9, then BMI grades I to IV from 23, 25, 27.6 and 32.5). The tool shows your BMI, its class, the normal range of weight for your height and a scale. BMI is for adults and is a screening number, not a diagnosis: it does not show muscle, age, sex or body shape. Talk to a doctor about your own health.

14. Lakh, Crore and Amounts in Words

Type an amount as digits (12,34,567 or 1,234,567) or with a word: thousand, lakh, crore, arab, kharab, million, billion or trillion (2.5 crore, 3 million), also several together (2 crore 50 lakh, 1 lakh crore). It shows the amount in the Indian and international systems, in lakh and crore and in millions and billions, and in words, as "Rupees ... Only" with paise for a cheque if you like. A table compares the two scales.

15. Your Data and Privacy

Every conversion is worked out by your browser; nothing you type is sent anywhere, and the address in your browser is not changed while you type. Saved pairs, recent conversions, the units you last used, pinned units, the values in the tools, your cities and your settings are kept in this browser on this device, and only after you change something. The browser's storage is not encrypted, and clearing this site's data deletes them; Reset everything in Settings removes them at once.

16. Keyboard and Accessibility

• / puts the cursor in the search bar; Alt+S swaps the two units and Alt+C copies the result (also while typing in the two number boxes); Esc closes the matches or a window. The keys work while the tool is in use: after a click or a tap in it.
• Tab reaches every button, menu and box; the tape is a slider for the arrow keys and tells screen readers both values.
• Results are announced to screen readers a moment after you stop typing.

17. How It Was Checked

The conversion code was checked on 101,252 cases in 13 groups. Every unit's size was worked out again from its published definition and compared with NIST's tables, conversions between every pair of units in each category were compared with a separate calculation, typed values were read back in all five number formats, and the smart search, the recipe scaler, the tyre code, number bases and amounts in words were each checked against a reference written from their rules. The original ConvertAll ran through the same check: it was still busy after 20 seconds on some long texts, and a saved name such as "constructor" or "__proto__" stopped it (421 of 3,003 saved states made to break it); this version answers those in milliseconds and ignores such names. The page was checked in a browser on phones and computers in both themes, including that it writes nothing to the browser on a first visit.

When UnitSwap was merged in on 15 November 2026, the changed conversion code was checked on 64,322 more cases: each of the 24 added units from its definition and against NIST's table, their names as people type them, everything the tool read and converted before against the version before it (210,120 searches and 230,340 entries in the number boxes, with only the differences that were meant), and every unit UnitSwap had against UnitSwap's own tables. That last comparison found one fault in UnitSwap itself: its milligram per cubic metre was 1,000 times too large. ConvertAll's is right.

18. Troubleshooting and Support

• "isn't a unit this app knows": check the spelling, or type the unit's symbol (such as psi or kWh). The search bar converts between categories it can tell apart.
• "That is too long": a box takes up to 200 characters.
• Copy did nothing: the browser blocked the clipboard; select the text and copy it yourself.
• My saved pairs were not kept: the browser blocks storage for this site, or its data was cleared.

For anything else, use the contact form. The FAQ answers the common questions.