Example 1
E = 10<sup>5</sup> N/C.
Electric Field Strength Calculator
Type force F [N] and charge q [C]. The calculator computes E = F/q: 0.1 N on 1e-6 C is 100,000 N/C, and 1 N on 1e-6 C is 1,000,000 N/C. q = 0 does not divide.
Field from a charge: E = k Q / r². Potential: V = W/q.
Result
Force F (N) and Charge q (C). The result shows up here.
How it works
Field strength from force and a test charge is E = F/q. At 0.1 N on 1 µC you get 1e5 N/C. At 0.02 N on 2 µC you get 1e4 N/C. At 1 N on 1 µC you get 1e6 N/C. 1 N/C = 1 V/m, so the same numbers in both units.
The form has two fields: F in newtons and q in coulombs. The result is in N/C. Type 1 µC as 1e-6, not as 1. A comma and a period mean the same F: 0,1 and 0.1.
q must not be zero, because you do not divide by zero. Typed 0 in q is rejected. Zero newtons at nonzero q gives E = 0. Both fields need a number before 1e5 N/C appears.
V = W/q is on the neighbouring page and computes potential in volts, not E. E = k Q / r² is on field from a point charge: there E from a source and a distance, here E from measured F and q. F = k q1 q2 / r² is on Coulomb force; here F is an input.
A negative q flips the sign of E. This calculator does not know r. It already takes F and q.
Type 0.1 and 1e-6, click Calculate, and check 1e5 N/C. Then 1 and 1e-6: 1e6 N/C. The calculator divides F by q; it does not guess a source charge.
How to use
- In the first field enter F in newtons, for example 0.1.
- In the second field enter q in coulombs, for example 1e-6. 1 µC is 1e-6, not 1.
- Click Calculate. 0.1 N and 1 µC give 1×10⁵ N/C. 1 N and 1e-6 C give 1×10⁶ N/C.
- q = 0 is rejected. Zero in F at nonzero q gives E = 0. Both fields need a number.
- For E = kQ/r², open field from a charge. Potential V = W/q is a different page.
Formula
E = F / q
Units: N/C = V/m. q ≠ 0.
E, F, and q for field strength
Field strength from force on a charge: E = F/q. 0.1 N on 1e-6 C is 100,000 N/C. 1 N on 1e-6 C is 1,000,000 N/C.
- E
- Field strength [N/C] (or V/m). 0.1 / 1e-6 = 1e5 N/C. Not energy ½CU².
- F
- Force on q [N]. 0.1 N or 1 N. Not the Lorentz force BIl.
- q
- Charge [C] that feels F. q = 0 does not divide.
Real-life examples
Example 2
E = 10<sup>4</sup> N/C.
Example 3
F = 1 N, q = 1e-6 C.
Example 4
F = 0.001 N, q = 1e-9 C.
Example 5
F = 0.05 N, q = -5e-7 C: sign of E.
Example 6
q = 2e-6 C -> E = 2.5e5 N/C.
Example 7
F = 1e-4 N, q = 1e-6 C.
Example 8
Fixed F = 0.2 N, q = 4e-6 C.
Example 9
F = 0.01 N, q = 100e-9 C.
Example 10
Same units as point-charge field.
Ways to use this calculator
- You compute 1×10⁵ N/C from 0.1 N and 1 µC.
- You compare with E = kQ/r² on field from a charge.
Frequently asked questions
How much E at 0.1 N and 1e-6 C?
Field strength is 1×10⁵ N/C, the same number in V/m. You divide 0.1 N by 1 µC.
How much at 1 N and 1e-6 C?
You get 1×10⁶ N/C. Ten times the force on the same charge gives ten times E.
Which units do I type?
Force F [N], charge q [C]. Result E [N/C]. 1 N/C = 1 V/m. Type 1 µC as 1e-6, not as 1.
How is this different from V = W/q?
Here E = F/q, field strength in N/C. There potential V [V] from work and charge. Different quantity, even though both divide by q.
How is this different from E = kQ/r²?
The calculator uses a measured force and a test charge. There you compute E from a source charge and a distance, with constant k.
Does a comma in 0.1 work?
Yes. 0.1 and 0,1 are the same F [N]. A comma and a period mean the same value.
Do I type 1 for 1 µC?
No. Field q wants q [C]. 1 µC is 1e-6 C. A bare 1 would make E a million times too small.
Where is F = k q1 q2 / r²?
On the Coulomb page. There the force between two charges. Here F is an input to E = F/q.
What about q = 0?
The calculator refuses zero coulombs. E = F/q at zero charge does not exist, because you do not divide by zero.
How much at 0.02 N and 2 µC?
Field strength is 1×10⁴ N/C. 0.02 / 2e-6. That is 10,000 N/C, or 10,000 V/m.
Knowledge sources
The formula is the school one. Units follow SI; NIST SP 330 and BIPM define the measures, not your result.
Page updated in 2026.