Pressure conversion chart
Pa, kPa, MPa, bar, atm, psi, Torr
Shop, HVAC, hydraulics, and process-plant pressures. Use the matrix for 1-unit factors, then the lookup table for common gauge values.
Free engineering resource
Engineering unit conversion chart pack
Printable pressure, power, and length charts you can actually keep open at a bench. HTML tables on this page, downloadable PDFs for each subject, and defined factors cited to NIST and BIPM. No currency or FX charts.
Reviewed 2026-09-13 · License CC BY 4.0
Power conversion chart
W, kW, hp, metric hp, BTU/h, RT
Motors, generators, HVAC, and engine ratings. Mechanical horsepower (550 ft·lbf/s) is the default hp column.
Length conversion chart
mm, cm, m, in, ft, yd, km, mi
Workshop, drawing, and site lengths using the 1959 international inch and foot. Bookmark the millimetre–inch table for fab work.
Defined conversion factors
Exact SI and conventional relationships first. Displayed lookup values are rounded for reading; the converters keep full precision from the same factor library.
| Relationship | Status | Note | Sources |
|---|---|---|---|
| 1 in = 25.4 mm | Exact | International inch, Yard and Pound Agreement (1959). 1 in = 0.0254 m exactly. | NIST |
| 1 ft = 0.3048 m | Exact | International foot = 12 × 0.0254 m. This pack does not use the obsolete US survey foot. | NIST |
| 1 yd = 0.9144 m | Exact | International yard = 3 international feet. | NIST |
| 1 mi = 1 609.344 m | Exact | Statute mile = 5 280 international feet. | NIST |
| 1 km = 1 000 m | Exact | SI prefix kilo (10³). | BIPM |
| 1 Pa = 1 N/m² | Exact | SI derived unit of pressure. | BIPMNIST |
| 1 bar = 100 000 Pa | Exact | The bar is accepted for use with the SI. 1 bar = 100 kPa exactly. | BIPMNIST |
| 1 atm = 101 325 Pa | Exact | Standard atmosphere. Distinct from 1 bar (100 000 Pa) and from technical atmosphere (at). | NIST atmNIST |
| 1 Torr = 101 325/760 Pa | Exact | Torr is defined from the standard atmosphere. Close to, but not identical to, 1 mmHg. | NIST |
| 1 psi ≈ 6 894.757 Pa | Derived | Pound-force per square inch, derived from the international pound and standard gravity. | NIST |
| 1 W = 1 J/s | Exact | SI derived unit of power. | BIPMNIST |
| 1 kW = 1 000 W | Exact | SI prefix kilo (10³). | BIPM |
| 1 hp (mechanical) = 745.699872 W | Derived | Mechanical horsepower = 550 ft·lbf/s. Motor nameplates often use this definition. | NIST |
| 1 hp (metric) = 735.499 W | Derived | Metric horsepower (PS / cv) ≈ 75 kgf·m/s. Do not mix with mechanical hp on datasheets. | NIST |
Pa, kPa, MPa, bar, atm, psi, Torr
Pressure conversion chart
Shop, HVAC, hydraulics, and process-plant pressures. Use the matrix for 1-unit factors, then the lookup table for common gauge values.
When to use: Spec sheets, compressor cut-in/cut-out, tire and vessel ratings, and lab work where psi, bar, and kPa appear on the same drawing.
1-unit factor matrix
Read a row, then across to the target unit. The cell is how many target units equal 1 of the row unit.
| 1 unit equals | Pa | kPa | MPa | bar | mbar | atm | psi | Torr |
|---|---|---|---|---|---|---|---|---|
| Pascal (Pa) | 1 | 0.001 | 1.0000e-6 | 1.0000e-5 | 0.01 | 9.8692e-6 | 0.000145038 | 0.00750062 |
| Kilopascal (kPa) | 1000 | 1 | 0.001 | 0.01 | 10 | 0.00986923 | 0.145038 | 7.50062 |
| Megapascal (MPa) | 1000000 | 1000 | 1 | 10 | 10000 | 9.86923 | 145.038 | 7500.62 |
| Bar (bar) | 100000 | 100 | 0.1 | 1 | 1000 | 0.986923 | 14.5038 | 750.062 |
| Millibar (mbar) | 100 | 0.1 | 0.0001 | 0.001 | 1 | 0.000986923 | 0.0145038 | 0.750062 |
| Standard atmosphere (atm) | 101325 | 101.325 | 0.101325 | 1.01325 | 1013.25 | 1 | 14.6959 | 760 |
| Pound-force per square inch (psi) | 6894.76 | 6.89476 | 0.00689476 | 0.0689476 | 68.9476 | 0.068046 | 1 | 51.7149 |
| Torr (Torr) | 133.322 | 0.133322 | 0.000133322 | 0.00133322 | 1.33322 | 0.00131579 | 0.0193368 | 1 |
Common psi values
Tire, compressor, and process pressures in kPa, bar, and atmospheres.
| psi | kPa | bar | atm | MPa |
|---|---|---|---|---|
| 1 | 6.89476 | 0.0689476 | 0.068046 | 0.00689476 |
| 5 | 34.4738 | 0.344738 | 0.34023 | 0.0344738 |
| 10 | 68.9476 | 0.689476 | 0.68046 | 0.0689476 |
| 14.696 | 101.325 | 1.01325 | 1 | 0.101325 |
| 15 | 103.421 | 1.03421 | 1.02069 | 0.103421 |
| 20 | 137.895 | 1.37895 | 1.36092 | 0.137895 |
| 30 | 206.843 | 2.06843 | 2.04138 | 0.206843 |
| 40 | 275.79 | 2.7579 | 2.72184 | 0.27579 |
| 50 | 344.738 | 3.44738 | 3.4023 | 0.344738 |
| 60 | 413.685 | 4.13685 | 4.08276 | 0.413685 |
| 80 | 551.581 | 5.51581 | 5.44368 | 0.551581 |
| 100 | 689.476 | 6.89476 | 6.8046 | 0.689476 |
| 120 | 827.371 | 8.27371 | 8.16552 | 0.827371 |
| 150 | 1034.21 | 10.3421 | 10.2069 | 1.03421 |
| 200 | 1378.95 | 13.7895 | 13.6092 | 1.37895 |
| 250 | 1723.69 | 17.2369 | 17.0115 | 1.72369 |
| 300 | 2068.43 | 20.6843 | 20.4138 | 2.06843 |
| 500 | 3447.38 | 34.4738 | 34.023 | 3.44738 |
| 1000 | 6894.76 | 68.9476 | 68.046 | 6.89476 |
| 1500 | 10342.1 | 103.421 | 102.069 | 10.3421 |
| 2000 | 13789.5 | 137.895 | 136.092 | 13.7895 |
| 3000 | 20684.3 | 206.843 | 204.138 | 20.6843 |
Common bar values
European and ISO process ratings in kPa, psi, and MPa.
| bar | kPa | psi | MPa | atm |
|---|---|---|---|---|
| 0.5 | 50 | 7.25189 | 0.05 | 0.493462 |
| 1 | 100 | 14.5038 | 0.1 | 0.986923 |
| 1.01325 | 101.325 | 14.6959 | 0.101325 | 1 |
| 2 | 200 | 29.0075 | 0.2 | 1.97385 |
| 3 | 300 | 43.5113 | 0.3 | 2.96077 |
| 4 | 400 | 58.0151 | 0.4 | 3.94769 |
| 5 | 500 | 72.5189 | 0.5 | 4.93462 |
| 6 | 600 | 87.0226 | 0.6 | 5.92154 |
| 8 | 800 | 116.03 | 0.8 | 7.89539 |
| 10 | 1000 | 145.038 | 1 | 9.86923 |
| 12 | 1200 | 174.045 | 1.2 | 11.8431 |
| 16 | 1600 | 232.06 | 1.6 | 15.7908 |
| 20 | 2000 | 290.075 | 2 | 19.7385 |
| 25 | 2500 | 362.594 | 2.5 | 24.6731 |
| 40 | 4000 | 580.151 | 4 | 39.4769 |
| 50 | 5000 | 725.189 | 5 | 49.3462 |
| 100 | 10000 | 1450.38 | 10 | 98.6923 |
| 160 | 16000 | 2320.6 | 16 | 157.908 |
| 250 | 25000 | 3625.94 | 25 | 246.731 |
| 400 | 40000 | 5801.51 | 40 | 394.769 |
- Tables are absolute conversion factors. Gauge pressure still needs atmospheric context (add or subtract 1 atm ≈ 101.325 kPa) when a datasheet mixes gauge and absolute.
- 1 atm (101.325 kPa) is not 1 bar (100 kPa). Mixing them is a common instrumentation error.
- Torr is 101 325/760 Pa by definition. Conventional millimetre of mercury (mmHg) is extremely close but is a separate conventional value.
W, kW, hp, metric hp, BTU/h, RT
Power conversion chart
Motors, generators, HVAC, and engine ratings. Mechanical horsepower (550 ft·lbf/s) is the default hp column.
When to use: Nameplate conversions, generator sizing, refrigeration tons, and comparing US mechanical hp with metric PS.
1-unit factor matrix
Read a row, then across to the target unit. The cell is how many target units equal 1 of the row unit.
| 1 unit equals | W | kW | MW | hp | hp(M) | BTU/h | RT |
|---|---|---|---|---|---|---|---|
| Watt (W) | 1 | 0.001 | 1.0000e-6 | 0.00134102 | 0.00135962 | 3.41214 | 0.000284345 |
| Kilowatt (kW) | 1000 | 1 | 0.001 | 1.34102 | 1.35962 | 3412.14 | 0.284345 |
| Megawatt (MW) | 1000000 | 1000 | 1 | 1341.02 | 1359.62 | 3412140 | 284.345 |
| Horsepower (mechanical) (hp) | 745.7 | 0.7457 | 0.0007457 | 1 | 1.01387 | 2544.43 | 0.212036 |
| Horsepower (metric) (hp(M)) | 735.499 | 0.735499 | 0.000735499 | 0.98632 | 1 | 2509.63 | 0.209136 |
| IT British thermal unit per hour (BTU/h) | 0.293071 | 0.000293071 | 2.9307e-7 | 0.000393015 | 0.000398466 | 1 | 8.3333e-5 |
| Ton of refrigeration (RT) | 3516.85 | 3.51685 | 0.00351685 | 4.71618 | 4.78159 | 12000 | 1 |
Common motor horsepower
NEMA / IEC motor sizes in kilowatts, watts, and metric horsepower.
| hp | kW | W | hp(M) | BTU/h |
|---|---|---|---|---|
| 0.25 | 0.186425 | 186.425 | 0.253467 | 636.108 |
| 0.5 | 0.37285 | 372.85 | 0.506935 | 1272.22 |
| 0.75 | 0.559275 | 559.275 | 0.760402 | 1908.33 |
| 1 | 0.7457 | 745.7 | 1.01387 | 2544.43 |
| 1.5 | 1.11855 | 1118.55 | 1.5208 | 3816.65 |
| 2 | 1.4914 | 1491.4 | 2.02774 | 5088.87 |
| 3 | 2.2371 | 2237.1 | 3.04161 | 7633.3 |
| 5 | 3.7285 | 3728.5 | 5.06935 | 12722.2 |
| 7.5 | 5.59275 | 5592.75 | 7.60402 | 19083.3 |
| 10 | 7.457 | 7457 | 10.1387 | 25444.3 |
| 15 | 11.1855 | 11185.5 | 15.208 | 38166.5 |
| 20 | 14.914 | 14914 | 20.2774 | 50888.7 |
| 25 | 18.6425 | 18642.5 | 25.3467 | 63610.8 |
| 30 | 22.371 | 22371 | 30.4161 | 76333 |
| 40 | 29.828 | 29828 | 40.5548 | 101777 |
| 50 | 37.285 | 37285 | 50.6935 | 127222 |
| 75 | 55.9275 | 55927.5 | 76.0402 | 190833 |
| 100 | 74.57 | 74570 | 101.387 | 254443 |
| 150 | 111.855 | 111855 | 152.08 | 381665 |
| 200 | 149.14 | 149140 | 202.774 | 508887 |
| 250 | 186.425 | 186425 | 253.467 | 636108 |
| 300 | 223.71 | 223710 | 304.161 | 763330 |
| 400 | 298.28 | 298280 | 405.548 | 1017770 |
| 500 | 372.85 | 372850 | 506.935 | 1272220 |
Common kilowatt ratings
IEC motor and generator ratings in mechanical hp and refrigeration tons.
| kW | hp | hp(M) | W | RT |
|---|---|---|---|---|
| 0.37 | 0.496178 | 0.50306 | 370 | 0.105208 |
| 0.55 | 0.737562 | 0.747792 | 550 | 0.15639 |
| 0.75 | 1.00577 | 1.01972 | 750 | 0.213259 |
| 1.1 | 1.47512 | 1.49558 | 1100 | 0.31278 |
| 1.5 | 2.01153 | 2.03943 | 1500 | 0.426518 |
| 2.2 | 2.95025 | 2.99117 | 2200 | 0.625559 |
| 3 | 4.02307 | 4.07886 | 3000 | 0.853035 |
| 4 | 5.36409 | 5.43848 | 4000 | 1.13738 |
| 5.5 | 7.37562 | 7.47792 | 5500 | 1.5639 |
| 7.5 | 10.0577 | 10.1972 | 7500 | 2.13259 |
| 11 | 14.7512 | 14.9558 | 11000 | 3.1278 |
| 15 | 20.1153 | 20.3943 | 15000 | 4.26518 |
| 18.5 | 24.8089 | 25.153 | 18500 | 5.26039 |
| 22 | 29.5025 | 29.9117 | 22000 | 6.25559 |
| 30 | 40.2307 | 40.7886 | 30000 | 8.53035 |
| 37 | 49.6178 | 50.306 | 37000 | 10.5208 |
| 45 | 60.346 | 61.183 | 45000 | 12.7955 |
| 55 | 73.7562 | 74.7792 | 55000 | 15.639 |
| 75 | 100.577 | 101.972 | 75000 | 21.3259 |
| 90 | 120.692 | 122.366 | 90000 | 25.5911 |
| 110 | 147.512 | 149.558 | 110000 | 31.278 |
| 132 | 177.015 | 179.47 | 132000 | 37.5336 |
| 160 | 214.564 | 217.539 | 160000 | 45.4952 |
| 200 | 268.204 | 271.924 | 200000 | 56.869 |
- Mechanical hp ≈ 745.700 W. Metric hp (PS) ≈ 735.499 W. A “100 hp” European motor is not the same power as a 100 hp US motor.
- 1 ton of refrigeration (RT) = 12 000 BTU/h ≈ 3.51685 kW. Used for chillers, not mechanical shaft power.
- Electrical horsepower (746 W exactly) is not shown here; use mechanical hp unless a standard calls out hp(E).
mm, cm, m, in, ft, yd, km, mi
Length conversion chart
Workshop, drawing, and site lengths using the 1959 international inch and foot. Bookmark the millimetre–inch table for fab work.
When to use: Machining tolerances, architectural dimensions, pipe and fastener callouts, and survey-adjacent site work that still uses feet and miles.
1-unit factor matrix
Read a row, then across to the target unit. The cell is how many target units equal 1 of the row unit.
| 1 unit equals | mm | cm | m | in | ft | yd | km | mi |
|---|---|---|---|---|---|---|---|---|
| Millimetre (mm) | 1 | 0.1 | 0.001 | 0.0393701 | 0.00328084 | 0.00109361 | 1.0000e-6 | 6.2137e-7 |
| Centimetre (cm) | 10 | 1 | 0.01 | 0.393701 | 0.0328084 | 0.0109361 | 1.0000e-5 | 6.2137e-6 |
| Metre (m) | 1000 | 100 | 1 | 39.3701 | 3.28084 | 1.09361 | 0.001 | 0.000621371 |
| Inch (in) | 25.4 | 2.54 | 0.0254 | 1 | 0.0833333 | 0.0277778 | 2.5400e-5 | 1.5783e-5 |
| Foot (ft) | 304.8 | 30.48 | 0.3048 | 12 | 1 | 0.333333 | 0.0003048 | 0.000189394 |
| Yard (yd) | 914.4 | 91.44 | 0.9144 | 36 | 3 | 1 | 0.0009144 | 0.000568182 |
| Kilometre (km) | 1000000 | 100000 | 1000 | 39370.1 | 3280.84 | 1093.61 | 1 | 0.621371 |
| Mile (mi) | 1609344 | 160934 | 1609.34 | 63360 | 5280 | 1760 | 1.60934 | 1 |
Workshop millimetres
Stock and fastener sizes in inches, centimetres, and metres.
| mm | in | cm | m |
|---|---|---|---|
| 1 | 0.0393701 | 0.1 | 0.001 |
| 2 | 0.0787402 | 0.2 | 0.002 |
| 3 | 0.11811 | 0.3 | 0.003 |
| 4 | 0.15748 | 0.4 | 0.004 |
| 5 | 0.19685 | 0.5 | 0.005 |
| 6 | 0.23622 | 0.6 | 0.006 |
| 8 | 0.314961 | 0.8 | 0.008 |
| 10 | 0.393701 | 1 | 0.01 |
| 12 | 0.472441 | 1.2 | 0.012 |
| 15 | 0.590551 | 1.5 | 0.015 |
| 16 | 0.629921 | 1.6 | 0.016 |
| 20 | 0.787402 | 2 | 0.02 |
| 25 | 0.984252 | 2.5 | 0.025 |
| 25.4 | 1 | 2.54 | 0.0254 |
| 30 | 1.1811 | 3 | 0.03 |
| 32 | 1.25984 | 3.2 | 0.032 |
| 40 | 1.5748 | 4 | 0.04 |
| 50 | 1.9685 | 5 | 0.05 |
| 75 | 2.95276 | 7.5 | 0.075 |
| 100 | 3.93701 | 10 | 0.1 |
| 150 | 5.90551 | 15 | 0.15 |
| 200 | 7.87402 | 20 | 0.2 |
| 250 | 9.84252 | 25 | 0.25 |
| 300 | 11.811 | 30 | 0.3 |
| 500 | 19.685 | 50 | 0.5 |
| 1000 | 39.3701 | 100 | 1 |
Fractional and whole inches
Drawing inches in millimetres, centimetres, and feet.
| in | mm | cm | ft |
|---|---|---|---|
| 0.0625 | 1.5875 | 0.15875 | 0.00520833 |
| 0.125 | 3.175 | 0.3175 | 0.0104167 |
| 0.25 | 6.35 | 0.635 | 0.0208333 |
| 0.375 | 9.525 | 0.9525 | 0.03125 |
| 0.5 | 12.7 | 1.27 | 0.0416667 |
| 0.625 | 15.875 | 1.5875 | 0.0520833 |
| 0.75 | 19.05 | 1.905 | 0.0625 |
| 1 | 25.4 | 2.54 | 0.0833333 |
| 1.5 | 38.1 | 3.81 | 0.125 |
| 2 | 50.8 | 5.08 | 0.166667 |
| 3 | 76.2 | 7.62 | 0.25 |
| 4 | 101.6 | 10.16 | 0.333333 |
| 6 | 152.4 | 15.24 | 0.5 |
| 8 | 203.2 | 20.32 | 0.666667 |
| 10 | 254 | 25.4 | 0.833333 |
| 12 | 304.8 | 30.48 | 1 |
| 18 | 457.2 | 45.72 | 1.5 |
| 24 | 609.6 | 60.96 | 2 |
| 36 | 914.4 | 91.44 | 3 |
| 48 | 1219.2 | 121.92 | 4 |
| 60 | 1524 | 152.4 | 5 |
Site and storey feet
Architectural and civil feet in metres, inches, and yards.
| ft | m | in | yd |
|---|---|---|---|
| 1 | 0.3048 | 12 | 0.333333 |
| 2 | 0.6096 | 24 | 0.666667 |
| 3 | 0.9144 | 36 | 1 |
| 4 | 1.2192 | 48 | 1.33333 |
| 5 | 1.524 | 60 | 1.66667 |
| 6 | 1.8288 | 72 | 2 |
| 8 | 2.4384 | 96 | 2.66667 |
| 10 | 3.048 | 120 | 3.33333 |
| 12 | 3.6576 | 144 | 4 |
| 15 | 4.572 | 180 | 5 |
| 16 | 4.8768 | 192 | 5.33333 |
| 20 | 6.096 | 240 | 6.66667 |
| 25 | 7.62 | 300 | 8.33333 |
| 30 | 9.144 | 360 | 10 |
| 40 | 12.192 | 480 | 13.3333 |
| 50 | 15.24 | 600 | 16.6667 |
| 75 | 22.86 | 900 | 25 |
| 100 | 30.48 | 1200 | 33.3333 |
- 1 inch = 25.4 mm exactly. Fractional inches in the lookup table use that exact relationship.
- This pack uses the international foot (0.3048 m), not the US survey foot (1200/3937 m). For new US work, NIST retired the survey foot in 2022–2023.
- Nautical miles (1 852 m exactly, BIPM) are not included here; use the aviation distance tools for NM.
Sources and methodology
Values come from the same conversion-factor library as the site calculators. Exact defined relationships are preserved. Displayed table cells are rounded to six significant figures for readability.
- BIPM — The International System of Units (SI Brochure, 9th edition)
Defines the SI base and derived units used in this pack, including the metre, pascal (N/m²), and watt (J/s).
Used for length, pressure, power
- NIST Special Publication 811 — Guide for the Use of the International System of Units (SI)
US guidance for SI usage and conversion factors, including the international inch, foot, yard, and mile.
Used for length, pressure, power
- NIST — SI Units
Plain-language NIST reference for SI base units and common derived engineering units.
Used for length, pressure, power
- NIST — Standard atmosphere (101 325 Pa)
The standard atmosphere is an exact conventional value: 1 atm = 101 325 Pa.
Used for pressure
Related machine-readable data: conversion-factors.csv and conversion-factors.json.
All pack downloads
- Download the full chart pack PDFPressure, power, and length tables in one printable PDF, with NIST/BIPM citations.
- Printable HTML packSame tables as a standalone HTML file — open and use File → Print → Save as PDF.
- Download pressure conversion chart PDFPressure conversion chart (PDF).
- Download power conversion chart PDFPower conversion chart (PDF).
- Download length conversion chart PDFLength conversion chart (PDF).
Related converters and charts
Engineering chart pack FAQs
Reuse, citation, and download questions for this free pressure, power, and length pack.
What is in the free engineering unit conversion chart pack?
Three cited reference charts — pressure (Pa, kPa, MPa, bar, atm, psi, Torr), power (W, kW, mechanical and metric hp, BTU/h, refrigeration tons), and length (mm, cm, m, in, ft, yd, km, mi). Each chart includes a 1-unit factor matrix, workshop lookup tables, a downloadable PDF, a printable HTML file, and links to the interactive converters.
Which sources do these engineering conversion charts cite?
SI units follow the BIPM SI Brochure (9th edition). US conversion factors and the international inch, foot, yard, and mile follow NIST Special Publication 811. The standard atmosphere (101 325 Pa) is the NIST conventional value. Exact defined relationships are marked “exact”; derived values such as psi and mechanical horsepower are rounded only for display.
Can I download these conversion charts as PDFs?
Yes. Download the combined engineering chart pack PDF, or grab the individual pressure, power, and length PDFs. Printable HTML copies are also provided if you prefer File → Print → Save as PDF from the browser.
May educators and resource pages reuse or embed this chart pack?
Yes. The pack is free to bookmark, print, share, and reuse under CC BY 4.0 with attribution to All Unit Conversions and a link to this page. Use the share and embed buttons for a ready-made citation, iframe, or converter widget snippet.
Does this pack include currency or FX charts?
No. This is an engineering measurement pack only — pressure, power, and length. Currency and exchange-rate charts are intentionally excluded.
How should I cite this engineering chart pack?
All Unit Conversions. (2026). Engineering unit conversion chart pack: pressure, power, and length. https://allunitconversions.com/charts/engineering-pack. Please keep the NIST/BIPM source links if you quote defined factors.